diff --git a/.gitignore b/.gitignore
index 37bee45..e97f437 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,16 @@
-#foo
+# OS cruft
+.DS_Store
+Thumbs.db
+
+# Editor/tooling
+.vscode/
+.idea/
+
+# Python (build-time tooling only, never shipped)
+__pycache__/
+*.pyc
+.venv/
+venv/
+
+# Serena MCP tool metadata (local dev-tool state, not project content)
+.serena/
diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..695592f
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,232 @@
+# Agent Instructions
+
+This repository is being developed interactively using Codex and Claude Code.
+
+## Repository structure
+
+This repo serves `erikson1970.github.io` as a whole:
+
+- `/` (root `index.html`, root `css/`) is a modest personal landing page —
+  not a project in its own right. Keep it simple and static.
+- `projects/<name>/` holds each individual project as a self-contained
+  static site (its own `index.html`, `css/`, `js/`, `data/`, etc.), reachable
+  at `erikson1970.github.io/projects/<name>/`. The first and (for now)
+  primary project is `projects/world-history/`, the world-history explorer
+  described throughout the rest of this file.
+- `ISSUES.md` and `TRACEABILITY.md` at the root are shared across the whole
+  repo (one continuous history, not split per project) — see "Issue and
+  requirement tracking" below.
+- `AGENTS.md` and `README.md` stay at the root as the overall primer; a
+  project may have its own `docs/` for project-specific detail (e.g.
+  `projects/world-history/docs/`).
+
+When adding a new project, give it its own `projects/<name>/` directory and
+link it from the root landing page; don't scatter its files into the shared
+root directories.
+
+## Project intent (`projects/world-history/`)
+
+Build a fully static, graphically rich, interactive world-history explorer for GitHub Pages.
+
+Do not introduce:
+
+- a production backend;
+- authentication;
+- a database server;
+- API keys;
+- runtime Python dependencies.
+
+Python is acceptable for build-time preprocessing.
+
+The same static-only, no-backend constraints apply to the root landing page
+and to any future project added under `projects/`.
+
+## Source of truth
+
+Excel files in `projects/world-history/source/` are the human-editable source data.
+
+Generated JSON in `projects/world-history/data/` should be reproducible from those files.
+
+Do not silently modify generated JSON in a way that cannot be recreated from the source workbook or build script.
+
+## Read first
+
+Before substantial work, read:
+
+- `README.md`
+- `projects/world-history/docs/STATUS.md`
+- `projects/world-history/docs/DATA_MODEL.md`
+- `projects/world-history/docs/VISUALIZATION.md`
+- `projects/world-history/docs/IMPLEMENTATION_PLAN.md`
+
+## Historical-data discipline
+
+Do not silently “correct” source-poster data using general knowledge.
+
+Distinguish among:
+
+1. data transcribed from the ChartOrigin poster;
+2. externally researched additions;
+3. implementation assumptions.
+
+When adding researched data, preserve source URL, notes, confidence, and uncertainty where appropriate.
+
+## IDs
+
+Stable IDs are important.
+
+Before renaming `box_id`, `seai_id`, `link_id`, or `segment_id`, search all dependent tables and generated files.
+
+Prefer migrations over casual renaming.
+
+## Wikipedia TODO URL
+
+This URL is an intentional placeholder:
+
+```text
+https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals
+```
+
+Treat it as `TODO`, not as actual metadata.
+
+## Initial stack preference
+
+Preferred progression:
+
+1. Plotly for rapid Sankey prototype;
+2. D3 if custom timeline/alluvial geometry is needed;
+3. ECharts is acceptable if it materially simplifies interaction.
+
+Do not prematurely rewrite a working prototype merely to change libraries.
+
+## Browser architecture
+
+Prefer plain HTML, CSS, modular JavaScript, and static JSON.
+
+Avoid framework introduction unless there is a demonstrated need.
+
+## Data build
+
+Implement validation as early as practical.
+
+The build should detect:
+
+- duplicate IDs;
+- broken foreign keys;
+- malformed years;
+- invalid population ranges;
+- unknown relation types.
+
+Warnings should include:
+
+- TODO URLs;
+- missing population;
+- low-confidence records.
+
+## Visualization semantics
+
+A Sankey/alluvial link does **not** mean literal conservation of people.
+
+Ribbon width means estimated historical scale unless a particular view explicitly defines another metric.
+
+Chronology must remain semantically correct.
+
+Do not allow an auto-layout to reorder nodes in a historically misleading way.
+
+## Accessibility
+
+Interactive marks should not require hover.
+
+Where practical:
+
+- click/tap selects;
+- keyboard access is available;
+- inspector mirrors tooltip information;
+- color is not the sole encoding.
+
+## Scope control
+
+Prefer small vertical slices:
+
+1. load data;
+2. validate;
+3. render a small subset;
+4. synchronize selection;
+5. add filtering;
+6. expand data coverage.
+
+Do not attempt to perfect every historical region before producing a working visualization.
+
+## Source control workflow
+
+`main` is treated as sacred, even though it is not branch-protected on GitHub.
+
+- Do work on `feature/<name>` or `fix/<name>` branches, never directly on `main`.
+- Merge to `main` only after a milestone's goal is verified closed (see
+  "Milestone review process" below).
+- Commit frequently on the working branch — small, real commits, not one
+  giant squash at the end.
+
+## Issue and requirement tracking
+
+- `ISSUES.md` tracks open defects/deferred work, each tagged **Gatekeeper**
+  (blocks the current milestone) or **Minor** (tabled — tracked, not
+  blocking).
+- `TRACEABILITY.md` tracks closure of stated requirements/goals (from this
+  file, `README.md`, and each project's own docs, e.g.
+  `projects/world-history/docs/DATA_MODEL.md` and
+  `projects/world-history/docs/IMPLEMENTATION_PLAN.md`) against verification
+  evidence.
+- Gatekeeper issues must be resolved (or explicitly reclassified as minor,
+  with reasoning) before a milestone branch merges to `main`. Minor issues
+  are fine to table indefinitely.
+
+## Milestone review process
+
+A **milestone branch** is one that closes out a numbered phase/milestone from
+a project's `docs/IMPLEMENTATION_PLAN.md` (e.g.
+`projects/world-history/docs/IMPLEMENTATION_PLAN.md`), a site-level change
+(e.g. the Milestone 3 root/`projects/` restructure), or `TRACEABILITY.md`
+generally (e.g. `feature/repo-reset` for Milestone 0). Small `fix/<name>`
+branches for sub-tasks within a milestone don't need their own council; only
+the milestone-closing merge to `main` does.
+
+Before that merge, close out the milestone by instantiating a small **council
+of experts**: independent reviewers (each a subagent with a distinct lens)
+who check the milestone's stated goal against the actual repo state — not a
+summary of it — and report findings. At minimum, run:
+
+1. a **data/content integrity** lens (whatever the milestone touched:
+   workbook, generated JSON, etc.);
+2. an **architecture/static-site constraints** lens (this file's Project
+   intent constraints, recommended structure, no leftover disposable
+   content);
+3. a **process & documentation consistency** lens (do `ISSUES.md` and
+   `TRACEABILITY.md` cross-reference each other correctly, do stated file
+   paths actually resolve, is anything stale) — do not skip this one; it has
+   caught real issues that the other two lenses miss.
+
+Whoever drives the merge (the session/agent orchestrating the milestone)
+reconciles the council's findings into `ISSUES.md` (new issues, filed at the
+correct severity) and `TRACEABILITY.md` (status updates), and fixes cheap
+wording/process nits inline rather than filing them. Each reviewer should
+report a `VERDICT: PASS | PASS_WITH_MINOR_ISSUES | FAIL` plus a `FINDINGS`
+list tagged `[gatekeeper]` or `[minor]`, citing concrete evidence (file
+paths, counts, quoted lines) rather than impressions.
+
+A milestone can close with tabled minor issues; it should not close with
+open gatekeeper issues, and a `FAIL` verdict from any reviewer blocks the
+merge until resolved or the finding is reclassified with stated reasoning.
+
+## Definition of done for v0.1 (`projects/world-history/`)
+
+A successful v0.1 of the world-history explorer:
+
+- runs as a static site;
+- loads generated JSON;
+- shows an interactive chronological Sankey/alluvial subset;
+- shows a simple timeline;
+- supports selecting a historical box;
+- updates an inspector;
+- supports at least one region filter;
+- is deployable directly to GitHub Pages.
diff --git a/HotelList.txt b/HotelList.txt
deleted file mode 100644
index 16d8cf7..0000000
--- a/HotelList.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-Near Natick Mall
-https://www.google.com/maps/place/Magnuson+Hotel+Framingham/@42.375724,-71.3588041,11.94z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e388899793653d:0x311c731fa3c55bd2
-https://www.google.com/maps/place/Crowne+Plaza+Boston-Natick/@42.375724,-71.3588041,11.94z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e38886b31319e7:0xce21e72878a39355
-https://www.google.com/maps/place/Boston%2FNatick+Travelodge/@42.297921,-71.5519922,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e38883dd75517d:0x34d43e2dd8208bba
-https://www.google.com/maps/place/Courtyard+Boston+Natick/@42.297921,-71.5519922,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e3889d9832d973:0x51b30ad7146c6cf1
-https://www.google.com/maps/place/Hampton+Inn+Boston%2FNatick/@42.2845889,-71.4135279,13z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x0000000000000000:0x90ce182cc66f4946
-https://www.google.com/maps/place/Red+Roof+Inn+Boston+-+Framingham/@42.2845889,-71.4135279,13z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x0000000000000000:0x20ff70aff91febc5
-
-
-On RT-9 in Framingham
-https://www.google.com/maps/place/Sheraton+Framingham+Hotel+%26+Conference+Center/@42.297921,-71.5519922,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e38a27a40998f7:0xc901f7bfb3e62eaa
-https://www.google.com/maps/place/Motel+6+Bstn-Frmgham/@42.297921,-71.5519922,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e38a26c0032c15:0x75e183388d06656
-
-
-On Rt-128
-https://www.google.com/maps/place/Hotel+Indigo+Boston+-+Newton+Riverside/@42.3339714,-71.3944735,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x89e383ba69fea8f3:0xd340c878a4e20c8a
-https://www.google.com/maps/place/Boston+Marriott+Newton/@42.3339714,-71.3944735,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x0000000000000000:0xe9780f9eba24e960
-
-On Rt-128 in Waltham
-https://www.google.com/maps/place/Embassy+Suites+by+Hilton+Boston%2FWaltham/@42.3339714,-71.3944735,11z/data=!4m5!1m2!2m1!1shotels+near+home!3m1!1s0x0000000000000000:0xcd882ff41d9ace68
diff --git a/ISSUES.md b/ISSUES.md
new file mode 100644
index 0000000..b157449
--- /dev/null
+++ b/ISSUES.md
@@ -0,0 +1,309 @@
+# Issues
+
+Open-issue tracker for `erikson1970.github.io` as a whole (the root landing
+page, `projects/world-history/`, and any future project) — one shared,
+continuous history, not split per project.
+
+Severity:
+
+- **Gatekeeper** — blocks closing the current milestone. Must be fixed or explicitly downgraded before merging the milestone branch to `main`.
+- **Minor** — tabled. Tracked but does not block milestone closure.
+
+Status: `Open`, `Tabled`, `Resolved`.
+
+An issue closed by a milestone council review notes which review closed it.
+
+**Path note:** issues filed before Milestone 3 refer to paths at the
+repository root (`docs/`, `source/`, `tools/`, `css/`, `js/`, `data/`) —
+accurate at the time. As of Milestone 3 those paths live under
+`projects/world-history/`. Historical entries are left as originally
+recorded rather than rewritten.
+
+---
+
+## Open
+
+_(none yet — see Tabled below)_
+
+## Tabled (minor, deferred)
+
+### ISSUE-001 — `Regions` rows lack a unique per-row identifier
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** `docs/DATA_MODEL.md`, workbook `Regions` sheet
+- **Description:** `region_id` is a grouping key shared by every country row in a region (e.g. `NE_SCAND` repeats once per country), not a unique row key. Fine for filtering today; will need a real per-row key (or a composite `region_id`+`country`) if `Regions` grows into real historical timelines per Phase 8.
+- **Deferred until:** Phase 8 (region expansion) or whenever a `Regions`-keyed foreign key is needed.
+
+### ISSUE-002 — All `Boxes`/`SEAIs` URLs are still the TODO placeholder
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** `docs/STATUS.md`
+- **Description:** Confirmed by validation: 198/198 `Boxes` rows and 83/83 `SEAIs` rows currently hold `https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals`. Expected at this stage; tracked here so it isn't mistaken for a data bug later.
+- **Deferred until:** "Add real Wikipedia URLs gradually" (STATUS.md recommended next work, priority 4).
+
+### ISSUE-003 — `Population` table has zero filled estimates
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** `docs/STATUS.md`
+- **Description:** All 390 seeded knot-point rows have no `population` value yet, by design (values intentionally not invented). No width-by-population rendering is possible until a representative subset is filled.
+- **Deferred until:** Phase 6 (population experiment); STATUS.md's recommended first-subset list (Roman, Byzantine, Persian, Ottoman, major Chinese dynasties, etc.).
+- **Note (Milestone 5):** This is why the Phase 4 timeline (`js/timeline.js`) has no population-based width mode: `js/state.js`'s `widthMode` field exists but has no UI control yet, deferred until this table has real values to render.
+
+### ISSUE-004 — `Links` and `BoxSegments` tables do not exist yet
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** `docs/DATA_MODEL.md`, `docs/STATUS.md`
+- **Description:** No succession/relationship data and no per-country-lane segmentation exist yet. Alluvial/Sankey view and accurate multi-country boxes (Rome, Ottomans, etc.) are blocked on these.
+- **Deferred until:** Phase 3 (`Links`, minimal subset) and Phase 7 (`BoxSegments`).
+- **Note (Milestone 4):** The `Links` half is now partially resolved — a 7-row hand-authored subset covering the Mediterranean/Europe cluster (`docs/IMPLEMENTATION_PLAN.md` Phase 3) exists and drives a working Sankey/alluvial prototype (see `TRACEABILITY.md` § Milestone 4). The China cluster and the rest of the dataset remain unlinked, and `BoxSegments` remains fully open (still deferred to Phase 7). Left open rather than closed since the title's `Links` scope is only partially covered.
+
+### ISSUE-006 — No automated test suite for `tools/wh_data.py`
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 1 implementation
+- **Description:** `build_data.py`/`validate_data.py` were exercised manually against the real workbook and against a deliberately corrupted copy (duplicate `box_id`, invalid `color_hex`, cascading FK break) to confirm the ERROR path genuinely blocks output. There's no repeatable test file for this yet.
+- **Deferred until:** whenever the validation logic grows complex enough that manual spot-checks stop being sufficient, or before a CI step is added.
+
+### ISSUE-005 — Six `Boxes` rows have no `start_year`
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Data-integrity council review of `source/world_history_chart_dataset_v2.xlsx`
+- **Description:** A handful of "Indigenous Era" boxes (e.g. `US_INDIG`, `CA_INDIG`, `AR_INDIG`, `AU_INDIG`) have a null `start_year` because the poster prints an illegible "c. [BCE]" with no parseable number there. `end_year` is always present, and `DATA_MODEL.md`'s rule only requires `start_year <= end_year` "when both exist," so this is not a validation-rule violation — just an open transcription gap, consistent with STATUS.md limitation #2.
+- **Resolution:** None yet. Left for whoever transcribes those boxes' start dates, or for the build script to render them with an explicit "unknown start" treatment.
+- **Note:** This entry was misfiled under `## Resolved` from Milestone 0 through Milestone 1 despite its own `Status:` field always saying `Tabled` — caught and moved here by the Milestone 1 process/docs council review.
+- **Note (Milestone 5):** `js/timeline.js`'s `buildTimelineLayout()` gives these six boxes exactly the "explicit unknown start treatment" this issue's resolution note anticipated — `approxStart: true`, with the bar's rendered start pinned to the current view's left edge rather than a fabricated year. Still not resolved (no real `start_year` has been transcribed), just no longer un-rendered.
+
+### ISSUE-007 — `wh_data.py` vocabulary-check loop has dead code for `estimate_method`
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 1 data-integrity council review
+- **Description:** The loop in `validate_population` iterates `for field_name in ("population_basis", "estimate_method")`, but the guard condition only fires for `field_name == "population_basis"`, so the `estimate_method` branch can never execute. Harmless today because `DATA_MODEL.md` §3 defines no recommended vocabulary for `estimate_method` (nothing is actually missed), but the code reads as if both fields are checked.
+- **Deferred until:** whenever `estimate_method` gets a real controlled vocabulary, or general pipeline cleanup.
+
+### ISSUE-008 — Malformed/corrupt source workbook produces a raw Python traceback, not a clean CLI error
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 1 data-integrity council review
+- **Description:** A truncated/non-zip `.xlsx` raises an uncaught `zipfile.BadZipFile` from inside `openpyxl.load_workbook`, and a workbook missing an expected sheet raises an uncaught `ValueError` from `wh_data.load_workbook`; neither is wrapped in a try/except in `build_data.py`/`validate_data.py`. Confirmed safe in both cases (exit code 1, no output written) — just not a clean `error:`-prefixed message like the already-handled missing-`--source`-file case.
+- **Deferred until:** whenever the CLI's error UX is revisited, or before non-maintainers start editing the workbook directly.
+
+### ISSUE-009 — No automated test suite for `js/app.js`/`js/data.js`/`js/state.js`
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 2 process/docs council review
+- **Description:** Parallel to ISSUE-006 but for the frontend: the Milestone 2 commit message documents real Node-based runtime verification (against a live local server and a minimal DOM stub), but none of it is a committed, repeatable test file — only prose in the commit message. ISSUE-006's title/scope is explicitly the Python pipeline (`tools/wh_data.py`) and does not cover this. The same gap recurred in Milestone 3: a Node `loadAllData()` run verified the moved `data/*.json` still loads correctly post-move, again only as prose (see `TRACEABILITY.md` M3-4, downgraded to Partial for this reason). Recurred a third time in Milestone 4: a Node fake-DOM harness verified the Sankey/Links integration (data load, box-list render, region-filter narrowing, box- and link-click-to-inspector, the accessible fallback list, and the Plotly-unavailable degradation path), but again only as commit-message/`TRACEABILITY.md` prose, not a committed test file (see `TRACEABILITY.md` M4-6/M4-8).
+- **Deferred until:** whenever `js/` grows complex enough that manual/ad-hoc verification stops being sufficient, or alongside ISSUE-006 if/when a test runner is introduced for either side.
+- **Note (Milestone 5):** Partially resolved rather than recurring a 4th time — `js/timeline.test.mjs` is a committed, repeatable test for `buildTimelineLayout()` (run with `node js/timeline.test.mjs`; a new root `package.json` with `"type": "module"` lets Node load it and `./timeline.js` directly, no scratch-copy workaround needed). `renderTimeline()`'s actual D3/DOM rendering and click-firing are still unverified (no real browser in this environment), and `sankey.js`/`app.js`/`data.js`/`state.js` remain entirely uncovered, so this issue stays open and Tabled rather than moving to Resolved.
+- **Note (Milestone 6):** A second module now has committed coverage — `js/sankey.test.mjs` (run with `node js/sankey.test.mjs`), covering `buildSankeyFigure()` (previously untested, Phase 3) and the new `computeSankeyHighlight()` (Phase 5). `applySankeySelection()`'s actual `Plotly.restyle` call, and `app.js`/`data.js`/`state.js` in full, remain uncovered — still Tabled, not Resolved.
+
+### ISSUE-010 — Milestone commits land as one (or two) large commits, not the "commit frequently" granularity AGENTS.md describes
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 2 process/docs council review
+- **Description:** AGENTS.md § Source control workflow says "commit frequently on working branch — small, real commits, not one giant squash at the end." All three milestones so far (0, 1, 2) each landed as one primary commit (plus, for 1 and 2, one small follow-up docs commit) rather than incremental commits during the work. Not flagged by either of the first two council reviews; caught on the third pass. No functional impact — each commit message is detailed and the work was verified as a unit before committing — but it's a real gap between written process and actual practice.
+- **Deferred until:** a decision on whether to tighten actual practice (commit more granularly mid-milestone going forward) or relax AGENTS.md's wording to match reality; not worth rewriting history on already-merged milestones.
+- **Note (Milestone 4):** Improved, not resolved — Milestone 4 split cleanly into three commits (data pipeline, UI, docs/traceability) instead of one or two, closer to but still short of the "small, real commits" ideal. Left open since Milestones 0–3 are unaffected and the practice isn't yet consistent enough to call this closed.
+- **Note (Milestone 5):** Regressed back to two commits (code, then docs/traceability) — not egregious (still a clean split, not a single squash), but not the three-commit improvement Milestone 4 made either. Practice still inconsistent; left open.
+- **Note (Milestone 7):** Regressed further — landed as a single commit bundling the new `js/timescale.js` module, the `js/timeline.js`/`js/sankey.js`/`js/app.js`/`index.html` integration, all three test files, and all docs/traceability updates together (flagged by that milestone's own architecture council review). Practice remains inconsistent milestone to milestone; left open.
+
+### ISSUE-011 — `Links` "transition year sensible" check is a loose union-envelope heuristic, not a real sensibility check
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 4 data-integrity council review
+- **Description:** `docs/DATA_MODEL.md` §8 lists "transition year sensible" as a `Links` validation rule. The actual implementation (`tools/wh_data.py` `validate_links`) checks only that the link's `year` falls within `[min(source.start_year, target.start_year), max(source.end_year, target.end_year)]` — the *union* of both boxes' lifespans, not their overlap or adjacency. A link between two boxes centuries apart could still pass this check if the chosen year happened to land inside the wider combined span. Not triggered by any of the current 7 rows (all pass cleanly and are historically accurate), and it's correctly scoped as a WARNING rather than a build-blocking ERROR, but the word "sensible" oversells what's actually verified.
+- **Deferred until:** whenever a real subset gets large/varied enough that this heuristic would plausibly miss a genuinely bad link, or general validation-logic cleanup.
+
+### ISSUE-012 — Timeline SVG doesn't re-render on window resize; a few prehistoric-landmark SEAIs can visually detach from their row if the year range is widened enough
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 5 architecture/accessibility council review
+- **Description:** Two independent minor gaps in `js/timeline.js`: (1) `renderTimeline()` computes SVG width once per render from `container.clientWidth`; unlike the Sankey/Plotly diagram (`responsive: true`), it only picks up a new width on the next state change, not on a bare window resize. (2) A few `seais.json` rows (e.g. `L15`/`PT_TRIBES` at year -3500, `L18`/`ES_IBERIAN` at -14500, `L21`/`FR_GAUL` at -17000) have a real numeric year that predates their parent box's own `start_year` by thousands of years — a pre-existing quirk in the data, not something `timeline.js` introduced. At the default `-3000..2026` view these are correctly excluded by the ordinary year-range filter, but if a user widens "From year" enough to bring one into view, its diamond marker clamps to the plot's left edge while its parent box's bar sits far to the right, which could read as misattributed.
+- **Deferred until:** (1) whenever the timeline gets enough real usage to justify a resize listener; (2) whenever those specific `seais.json` rows are reviewed for whether their year, their parent `box_id`, or both need correcting — likely alongside whatever eventually addresses ISSUE-005's prehistoric-era boxes generally.
+
+### ISSUE-013 — Semantic-zoom time scale changes snap instantly, not smoothly animated
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 7 (Phase 5.5) implementation, `docs/timescaleRequirement.md` § Zoom Interaction
+- **Description:** That doc explicitly frames smooth animation while zooming/dragging the time-compression slider or year-range inputs as optional ("if technically practical, animate the layout smoothly"). The current implementation (`js/timeline.js`'s full SVG redraw per state change, `js/sankey.js`'s `applySankeyTimeScale()` via `Plotly.restyle`) recomputes and redraws positions immediately on every `input` event with no transition/tween, so bars, markers, ticks, and Sankey nodes jump to their new position each frame rather than easing.
+- **Deferred until:** real usage suggests the instant-snap behavior is actually distracting/hard to track at the current ~198-box, small-Links-subset scale; would likely mean D3 `.transition()` calls in `renderTimeline()` and a Plotly `layout.transition`/animated `restyle` for the Sankey side.
+
+### ISSUE-014 — Time-scale slider's continuous `input` updates re-render every panel, not just the ones that depend on it
+- **Severity:** Minor
+- **Status:** Tabled
+- **Source:** Milestone 7 (Phase 5.5) council review (accessibility/UX lens)
+- **Description:** `js/app.js`'s single `store.subscribe` callback re-runs `renderList` (rebuilds the ~198-item box list), `renderInspector`, `renderTimelineView`, `renderAlluvialListSelection`, `renderSankeySelection`, and `renderSankeyTimeScale` on every state change, including the new `#time-scale` slider's `input` event — which can fire many times per second during a drag or a held arrow key. Only `renderTimelineView` and `renderSankeyTimeScale` actually depend on `timeScale`; the rest do redundant work each tick. `docs/timescaleRequirement.md`'s own Performance section recommends updating only x-related geometry where possible. Unlikely to be noticeably slow at the current ~198-box/7-link scale (the pre-existing region/year filters already do a full box-list rebuild on `change`, just far less frequently), but this is the first control wired to a high-frequency event, and the gap is real and unaddressed.
+- **Deferred until:** real usage shows jank during a slider drag, or the dataset grows enough (more boxes, a larger `Links` subset) to make the redundant work costly — likely fix is either narrowing what `store.subscribe` re-renders per patch (e.g. a per-field subscription) or `requestAnimationFrame`-throttling the slider's `store.set` calls.
+
+## Resolved
+
+### ISSUE-000 — Repo contained an unrelated portfolio template and stray files
+- **Severity:** Gatekeeper
+- **Status:** Resolved
+- **Description:** `index.html` and `static/` held a generic "Portfolio template" theme (Lorem Ipsum, fake bios) unrelated to this project; `HotelList.txt` (personal hotel-search links) and `chat_log.md` (dead sandbox links from doc handoff) were also present.
+- **Resolution:** Removed `static/`, `HotelList.txt`, `chat_log.md`; replaced `index.html` with a minimal placeholder. Closed by Milestone 0 council review.
+
+## Milestone council reviews
+
+### Milestone 0 — Repository reset & data intake
+Reviewed 2026-09-06 against commit `3f84688` (branch `feature/repo-reset`), three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data integrity | PASS |
+| Static-site architecture / constraints | PASS |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No gatekeeper findings. The process/docs reviewer's minor findings (severity-field enum drift on a resolved issue, no per-entry `Status:` field, ambiguity in `AGENTS.md`'s milestone-review process) were fixed inline in this document and in `AGENTS.md` rather than filed as separate issues. Milestone approved to merge to `main`.
+
+### Milestone 1 — Data build pipeline
+Reviewed 2026-09-06 against commit `74459d7` (branch `feature/build-data-pipeline`), three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data integrity | PASS |
+| Static-site architecture / constraints | PASS |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No gatekeeper findings. New minor issues filed: ISSUE-007 (dead code in a vocabulary-check loop), ISSUE-008 (raw traceback on a malformed/corrupt workbook instead of a clean CLI error). The process reviewer's misfiled-`ISSUE-005` finding was fixed inline (moved from `## Resolved` to `## Tabled`, matching its own `Status:` field). Also fixed inline: `tools/README.md` now points at `tools/requirements.txt`, and `docs/STATUS.md` was refreshed to mention the build/validation pipeline. Milestone approved to merge to `main`.
+
+### Milestone 2 — Minimal static application
+Reviewed 2026-09-06 against commits `7511bee`/`3881455` (branch `feature/minimal-app`), three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data integrity | PASS_WITH_MINOR_ISSUES |
+| Static-site architecture / constraints & accessibility | PASS |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No gatekeeper findings. Fixed inline (real code/docs changes, not just tabled):
+- **Sort-order bug** (data-integrity finding): `filteredBoxes` in `js/app.js` sorted the 6 null-`start_year` boxes from ISSUE-005 by their *end* year, misplacing e.g. `US_INDIG` (prehistory–1607) next to 16th–century boxes instead of near other prehistoric-start entities. Changed the fallback from `?? end_year ?? 0` to `?? Number.NEGATIVE_INFINITY` so these boxes sort to the front, consistent with them representing the earliest, least-precisely-dated era for their region.
+- **Unhandled rejection** (architecture finding): `main()`'s call site had no `.catch()`, so a rendering-time error (as opposed to a fetch failure, already handled) would only produce a silent console warning. Added `main().catch(...)` routing to the same `setStatus(..., true)` error display.
+- **Stale `js/README.md`** (process finding): rewritten to describe the actual `data.js`/`state.js`/`app.js` split instead of a since-superseded planned module list.
+- **Stale `docs/STATUS.md`** (process finding): refreshed to mention the Phase 2 prototype and mark "Build first interactive prototype" done.
+
+New minor issues filed (tabled, not gatekeepers): ISSUE-009 (no automated test suite for the new `js/` modules, parallel to ISSUE-006), ISSUE-010 (milestones have landed as one or two large commits rather than the frequent-small-commits granularity AGENTS.md describes — a process/practice gap, not unique to this milestone). Milestone approved to merge to `main`.
+
+### Milestone 3 — Site restructure
+Reviewed 2026-09-06 against commit `ce8b234` (branch `feature/site-restructure`), three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Path & link integrity | PASS |
+| Static-site architecture / constraints & accessibility | PASS_WITH_MINOR_ISSUES |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No gatekeeper findings. Fixed inline (real code/docs changes, not just tabled):
+- **Missing heading on project cards** (architecture/accessibility finding): `.project-card` links weren't wrapped in a heading, so screen-reader users navigating by heading list would miss per-project headings once more cards are added. Wrapped the link in an `<h3>` in `index.html` and updated `css/site.css` selectors accordingly.
+- **Missing `fonts.googleapis.com` preconnect** (architecture finding, trivial performance nit): added the second `<link rel="preconnect">` alongside the existing `fonts.gstatic.com` one.
+- **Stale `README.md` section citations in `TRACEABILITY.md`** (process finding): Milestones 0–2's requirement rows cite "README.md § ..." headings that moved wholesale to `projects/world-history/README.md` in Milestone 3; the existing "Path note" only covered directory paths, not this. Extended the note to explain the README content relocation too.
+- **M3-4 evidence overstated** (process finding): the requirement's "Met" status rested partly on a Node `loadAllData()` run that, like Milestone 2's equivalent checks (ISSUE-009), was never captured as a committed, repeatable test — only asserted in prose. Downgraded M3-4 to Partial in `TRACEABILITY.md` and extended ISSUE-009's description to note the recurrence.
+
+Noted, not newly filed: Milestone 3 again landed as two large commits (`121b4ff`, `ce8b234`), consistent with the already-tabled ISSUE-010 rather than a new or worsened gap. Milestone approved to merge to `main`.
+
+### Milestone 4 — Plotly alluvial prototype (Phase 3)
+Reviewed against commits `e363906`/`be635c9`/`65f38ab` (branch
+`feature/alluvial-prototype`), three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data / content integrity | PASS_WITH_MINOR_ISSUES |
+| Architecture / static-site constraints & accessibility | PASS_WITH_MINOR_ISSUES |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No gatekeeper findings. Fixed inline (real code/docs changes, not just tabled):
+- **No keyboard/AT access to Sankey links** (architecture/accessibility finding): Plotly's SVG hit-targets are mouse-only with no tabindex, and unlike box selection (already a real `<button>` list), a link had no accessible alternative at all. Added `#alluvial-list`, a visually-hidden-but-focusable `<ul>` of real `<button>`s (`.visually-hidden`/`:focus-within` in `css/history.css`) driving the same `selectedLinkId` as a Plotly click.
+- **Dark-theme bug** (architecture finding): Plotly's default opaque-white `paper_bgcolor`/`plot_bgcolor` rendered as a stark white rectangle in dark mode. `renderSankey()` now reads the page's own `--bg`/`--fg` CSS custom properties via `getComputedStyle` and passes them into `layout`.
+- **`links.json` fetch failure could take down the whole page** (architecture finding): `loadAllData()` originally fetched all tables via one `Promise.all`, so a broken/missing `links.json` — feeding only the peripheral Sankey prototype — would fail the box list, inspector, and region filter too. Split into required (`boxes`/`seais`/`population`/`regions`, still hard-failing) and optional (`links`, defaults to `[]` with a `console.warn`) fetches.
+- **NaN edge case** (architecture finding): `buildSankeyFigure()`'s `Math.min(...years)`/`Math.max(...years)` over an empty array (every referenced box has a null `start_year`, per ISSUE-005) would silently produce `NaN` node x-positions (`-Infinity || 1` is still `-Infinity`, a truthy value in JS). Guarded with a length check.
+- **Un-awaited Plotly promise** (architecture finding): `renderSankey()` called `Plotly.newPlot` without awaiting it, so an asynchronous rejection (as opposed to a synchronous throw) would bypass `js/app.js`'s intended fallback message and surface only as an unhandled-rejection console warning. Made `renderSankey()` `async`, `await`ed the call, and `await`ed the call site inside the existing try/catch.
+- **Misleading UI copy** (process finding): the alluvial section's note didn't disclose that it covers only a 7-row hand-authored subset, not the full dataset. Reworded to name the exact 7 successions.
+- **JSDoc gap** (process finding): `buildSankeyFigure()`'s doc comment didn't explain the `arrangement: "fixed"` chronology-preservation rationale. Extended.
+- **Opaque validation error** (data-integrity finding): `validate_links()` gave the same generic message for both "missing `relation_type`" and "`relation_type` not in the controlled vocabulary." Split into two distinct messages.
+
+New minor issue filed (tabled, not a gatekeeper): ISSUE-011 (the `Links` "transition year sensible" check is a loose union-envelope heuristic, not a real overlap-adjacency check). ISSUE-004 noted as partially addressed (small Mediterranean/Europe `Links` subset now exists); ISSUE-009 extended for a third recurrence (Node fake-DOM harness verification, again only commit-message/prose, not a committed test file); ISSUE-010 noted as improved (three commits this milestone instead of one or two). Milestone approved to merge to `main`.
+
+**Note (added retroactively during the Milestone 5 review):** this section
+was missing from `ISSUES.md` despite `TRACEABILITY.md`'s Milestone 4 section
+and commit `09eea5f` ("Milestone 4 council review: reconcile findings, close
+out") both referring to it — caught by the Milestone 5 process/docs council
+review and backfilled here from that commit's actual history rather than
+left broken.
+
+### Milestone 5 — D3 timeline prototype (Phase 4)
+Reviewed against commits `d80728f`/`212409b` (branch `feature/timeline-view`),
+three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data / content integrity | PASS_WITH_MINOR_ISSUES |
+| Architecture / static-site constraints & accessibility | PASS_WITH_MINOR_ISSUES |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+Two gatekeeper findings, both about this repo's own docs disagreeing with
+themselves, both fixed inline rather than tabled — see `TRACEABILITY.md`'s
+Milestone 5 council-review note for the full list (reversed year-range bug,
+dead SEAI tooltip, wrong evidence numbers/citations, the V1-4 supersession
+row, and closing ISSUE-009's recurrence with an actual committed test file,
+`js/timeline.test.mjs`, instead of tabling it a fourth time). New minor
+issue filed: ISSUE-012 (no resize re-render; a few prehistoric-landmark
+SEAIs can visually detach from their row if the year range is widened
+enough). ISSUE-005/ISSUE-003 annotated with this milestone's use of them;
+ISSUE-010 noted as regressed to two commits. This Milestone 4 section was
+also backfilled during this review (see note above). Milestone approved to
+merge to `main`.
+
+### Milestone 6 — Cross-panel selection sync (Phase 5)
+Reviewed against commit `6e5681a` (branch `feature/shared-interaction`),
+three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Correctness & data-fidelity | PASS |
+| Accessibility & UX | PASS_WITH_MINOR_ISSUES |
+| Architecture & docs/process | PASS_WITH_MINOR_ISSUES |
+
+Two gatekeeper findings, both fixed inline rather than tabled — see
+`TRACEABILITY.md`'s Milestone 6 council-review note for the full list
+(the Sankey selected-link color-only encoding, and this section's own
+missing Milestone 6 note, backfilled now rather than left broken). No new
+issue filed. Milestone approved to merge to `main`.
+
+### Milestone 7 — Semantic zoom time scale (Phase 5.5)
+Reviewed against commit `887f483` (branch `feature/semantic-zoom-scale`)
+vs. `main` at `2df28c3`, three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Correctness & data-fidelity | PASS |
+| Accessibility & UX | PASS_WITH_MINOR_ISSUES |
+| Architecture & docs/process | PASS |
+
+One gatekeeper finding, fixed inline: `js/timeline.js`'s `formatTickYear`
+rendered a tick landing on calendar year 0 as "0 CE" — a year that doesn't
+exist under this dataset's own documented BCE/CE convention
+(`docs/DATA_MODEL.md`: "There is no attempt to model a historical year
+zero"), and the app's own default `-3000..2026` view produces exactly such
+a tick. Fixed at the source: `js/timescale.js`'s `timeTicks()` now excludes
+an exact-0 candidate (covered by a new `timescale.test.mjs` assertion);
+`formatTickYear` itself also now guards year 0 (and the `-0` `Math.round`
+can produce) in case it's ever reused for a hover/inspector display of an
+exact year, per `docs/timescaleRequirement.md`'s own recommendation.
+
+Minor findings, two fixed inline, two tabled:
+- Fixed: `js/sankey.test.mjs` didn't exercise `computeSankeyNodeX`'s
+  null-`start_year` fallback (ISSUE-005) with any real data — added a
+  synthetic-box case.
+- Fixed: `js/timeline.js`'s tick rendering recomputed `scale.yearToX(year)`
+  a second time per tick instead of reusing the `x` `buildTimelineLayout`
+  already put on each `layout.ticks` entry — simplified to reuse it.
+- Tabled as ISSUE-013: smooth animation while zooming/dragging isn't
+  implemented — explicitly optional in `docs/timescaleRequirement.md`.
+- Tabled as ISSUE-014: the new time-scale slider's `input` listener
+  triggers a full re-render of every panel (not just the ones that
+  actually depend on `timeScale`) on every drag tick — no debounce/RAF
+  throttle exists. Unlikely to matter at the current dataset scale.
+
+ISSUE-010 (milestone commit granularity) noted as regressed further this
+milestone (a single commit, where Milestone 4 managed three and Milestone
+5/6 managed two) — see that issue's own Milestone 7 note. Milestone
+approved to merge to `main`.
diff --git a/README.md b/README.md
index 552e434..705b927 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,31 @@
 # erikson1970.github.io
+
+Personal site and project host for [erikson1970](https://github.com/erikson1970), served via GitHub Pages.
+
+## Structure
+
+```text
+/
+├── index.html         landing page (this repo's root)
+├── css/                landing-page styles only
+└── projects/
+    └── world-history/  World History Explorer — see projects/world-history/README.md
+```
+
+The root is a small, static landing page — no framework, no backend, no
+build step. Each project lives in its own `projects/<name>/` directory as a
+self-contained static site, reachable at
+`erikson1970.github.io/projects/<name>/`, and is free to have its own
+`css/`, `js/`, `data/`, `docs/`, etc.
+
+`ISSUES.md` and `TRACEABILITY.md` at the root track defects/deferred work
+and requirement closure across the whole repo — one continuous history, not
+split per project. See `AGENTS.md` for the full development workflow
+(branching, milestone council reviews, issue/traceability tracking).
+
+## Projects
+
+- **[World History Explorer](projects/world-history/)** — an interactive,
+  static visualization of world history built from the ChartOrigin
+  *Timeline of World History* poster. See
+  `projects/world-history/README.md` for details.
diff --git a/TRACEABILITY.md b/TRACEABILITY.md
new file mode 100644
index 0000000..585c016
--- /dev/null
+++ b/TRACEABILITY.md
@@ -0,0 +1,429 @@
+# Traceability
+
+Maps stated requirements/goals to verification status. Updated at each milestone
+council review (see `AGENTS.md` § Milestone review process). Not a substitute for
+`ISSUES.md` — this tracks *closure of stated requirements*, `ISSUES.md` tracks
+*defects and deferred work*.
+
+Status values: `Met`, `Partial`, `Not started`, `Deferred` (explicitly out of scope for the milestone that recorded it, not merely unstarted — see M6-6).
+
+**Path note:** Milestones 0–2 below predate the Milestone 3 restructure and
+refer to `index.html`, `css/`, `js/`, `data/`, `source/`, `tools/`, and
+`docs/` at the repository root — accurate at the time each was written. As
+of Milestone 3, the world-history project (and those paths) live under
+`projects/world-history/`; see the Milestone 3 section. Historical entries
+are left as originally recorded rather than rewritten. This also applies to
+`README.md` section citations below (e.g. "README.md § Recommended site
+structure", "§ Data authority", "§ core idea"): that content moved wholesale
+to `projects/world-history/README.md` in Milestone 3 — the root `README.md`
+today only has `## Structure` and `## Projects` sections. Follow the cited
+section name into `projects/world-history/README.md` instead.
+
+---
+
+## Milestone 0 — Repository reset & data intake
+
+Goal (`AGENTS.md` Phase 0 / `IMPLEMENTATION_PLAN.md` Phase 0): replace disposable
+repo contents with a clean project structure and bring the source workbook in.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M0-1 | Recommended site structure in place (`index.html`, `css/`, `js/`, `data/`, `source/`, `tools/`, `docs/`) | README.md § Recommended site structure | Met | Directories created; docs moved into `docs/`; workbook moved into `source/` |
+| M0-2 | Docs readable from paths `AGENTS.md`/README point to | AGENTS.md § Read first | Met | `docs/STATUS.md`, `docs/DATA_MODEL.md`, `docs/VISUALIZATION.md`, `docs/IMPLEMENTATION_PLAN.md` now exist at those paths |
+| M0-3 | No disposable/unrelated content remains | README.md § Purpose ("current contents disposable") | Met | Portfolio-template `index.html`/`static/`, `HotelList.txt`, `chat_log.md` removed |
+| M0-4 | Excel workbook present as source of truth | README.md § Data authority | Met | `source/world_history_chart_dataset_v2.xlsx` added |
+| M0-5 | Workbook row counts match documented counts | docs/STATUS.md | Met | Verified: Boxes 198/198, SEAIs 83/83, Population 390/390, Regions 89/89 |
+| M0-6 | No production backend/DB/auth/API keys introduced | AGENTS.md § Project intent | Met | Reset introduced only static assets and docs |
+
+### Data validation spot-checks (informational, feeds Phase 1 `validate_data.py`)
+
+| Check | Result |
+|---|---|
+| Duplicate `box_id` | none found (198 unique) |
+| `start_year <= end_year` | holds for all rows with both years present |
+| `color_hex` matches `#RRGGBB` | all 198 valid |
+| `box_id` confidence vocabulary in use | `High`, `Medium` |
+| Duplicate `seai_id` | none found (83 unique) |
+| Orphan `SEAIs.box_id` (no matching Box) | none |
+| Orphan `Population.box_id` (no matching Box) | none |
+| TODO placeholder URL count | Boxes 198/198, SEAIs 83/83 (expected — see ISSUE-002) |
+| `Population.population` filled | 0/390 (expected — see ISSUE-003) |
+| Duplicate `Regions.region_id` | 5 groups repeat by design, one row per country (see ISSUE-001) |
+
+### Milestone 0 council review
+
+Reviewed 2026-09-06 against commit `3f84688`: data integrity PASS, static-site
+architecture/constraints PASS, process & documentation consistency
+PASS_WITH_MINOR_ISSUES (wording/process nits, no gatekeeper findings — see
+`ISSUES.md` § Milestone council reviews). Merged to `main`.
+
+## Milestone 1 — Data build pipeline
+
+Goal (`docs/IMPLEMENTATION_PLAN.md` Phase 1): convert the Excel workbook to
+validated JSON, failing the build on structural problems and warning on
+content-quality issues.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M1-1 | Build script reads `source/*.xlsx`, writes `data/*.json` | README.md § Data authority, IMPLEMENTATION_PLAN.md Phase 1 | Met | `tools/build_data.py`; run produces `data/{boxes,seais,population,regions}.json` |
+| M1-2 | Fails on duplicate IDs | IMPLEMENTATION_PLAN.md Phase 1 | Met | `wh_data.py` `validate_boxes`/`validate_seais`/`validate_population`; verified against an injected duplicate `box_id` (exit 1, no output written) |
+| M1-3 | Fails on broken foreign keys | IMPLEMENTATION_PLAN.md Phase 1 | Met | `SEAIs.box_id`/`Population.box_id` checked against `Boxes`; verified via injected corruption (cascading FK errors correctly detected) |
+| M1-4 | Fails on malformed years | IMPLEMENTATION_PLAN.md Phase 1 | Met | numeric-type check on all year fields |
+| M1-5 | Fails on invalid population ranges | IMPLEMENTATION_PLAN.md Phase 1 | Met | `population > 0`, `low <= population <= high` |
+| M1-6 | Fails on unknown relation types | IMPLEMENTATION_PLAN.md Phase 1 | Not started | No `Links` table exists yet (tracked as ISSUE-004); nothing to validate until Phase 3 |
+| M1-7 | Warns on TODO URLs, missing population, low-confidence records, suspicious dates | IMPLEMENTATION_PLAN.md Phase 1 | Met | Verified: real workbook run produces exactly 671 warnings (198 Box + 83 SEAI TODO URLs, 390 unfilled Population rows), 0 errors |
+| M1-8 | `data/*.json` reproducible from `source/*.xlsx`, never hand-edited | AGENTS.md § Source of truth | Met | `data/README.md` states the rule; build overwrites deterministically on every run |
+| M1-9 | No runtime Python — build-time only | AGENTS.md § Project intent | Met | `tools/` scripts run only at build time; no Python referenced from `index.html`/`js/` |
+
+### Milestone 1 council review
+
+Reviewed 2026-09-06 against commit `74459d7`: data integrity PASS, static-site
+architecture/constraints PASS, process & documentation consistency
+PASS_WITH_MINOR_ISSUES (a misfiled issue entry and two stale-docs nits, no
+gatekeeper findings — see `ISSUES.md` § Milestone council reviews). Merged to
+`main`.
+
+## Milestone 2 — Minimal static application
+
+Goal (`docs/IMPLEMENTATION_PLAN.md` Phase 2): a genuinely interactive first
+slice on top of Phase 1's generated JSON — separate data loading, state
+management, and rendering; select a box and see an inspector; at least one
+filter.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M2-1 | Data loading is a separate module from rendering/state | IMPLEMENTATION_PLAN.md Phase 2 | Met | `js/data.js` only fetches/indexes; no DOM references |
+| M2-2 | State management is a separate, minimal module | IMPLEMENTATION_PLAN.md Phase 2 | Met | `js/state.js`: `createStore()` (get/set/subscribe), no rendering logic |
+| M2-3 | Runs as a static site with no build step | AGENTS.md § Project intent | Met | Plain ES modules loaded via `<script type="module">`; no bundler |
+| M2-4 | Select a historical box | README.md § core idea, V1-5 | Met | Box list items are `<button>`s; click toggles `selectedBoxId` |
+| M2-5 | Updates an inspector | README.md § core idea, V1-6 | Met | `renderInspector` shows name/dates/region/span/confidence/notes/url/SEAIs |
+| M2-6 | At least one region filter | README.md § core idea, V1-7 | Met | `region-filter` `<select>` populated from `regionGroups()`, filters the list |
+| M2-7 | Interactive marks don't require hover; keyboard-accessible | AGENTS.md § accessibility | Met | Real `<button>` elements (native click + Enter/Space + Tab focus); `:focus-visible` style in `css/history.css` |
+| M2-8 | Color is not the sole encoding for selection state | AGENTS.md § accessibility | Met | Selected item also gets bold text + a checkmark (`::before`), not just background color |
+| M2-9 | Runtime behavior verified, not just claimed | Process norm established during Milestone 1 (not yet written into AGENTS.md) | Partial | Node (built-in fetch) against a local static server + a minimal DOM stub: `loadAllData`/`regionGroups` against real `data/*.json`, `createStore` pub-sub semantics, full `app.js` wiring (click-to-select, filter narrowing, selection-clear-on-filter-change) — verification performed and independently reproduced by the Milestone 2 data-integrity/architecture council reviewers, but not captured as a committed, repeatable test file (see ISSUE-009) |
+
+### Milestone 2 council review
+
+Reviewed 2026-09-06 against commits `7511bee`/`3881455`: data integrity
+PASS_WITH_MINOR_ISSUES, static-site architecture/constraints & accessibility
+PASS, process & documentation consistency PASS_WITH_MINOR_ISSUES. No
+gatekeeper findings; a real sort-order bug and an unhandled-rejection gap
+were fixed inline, `js/README.md`/`docs/STATUS.md` refreshed, two new minor
+issues tabled (ISSUE-009, ISSUE-010) — see `ISSUES.md` § Milestone council
+reviews. Merged to `main`.
+
+## Milestone 3 — Site restructure
+
+Goal (user request, relayed 2026-09-06): make the repository root a modest
+personal landing page for erikson1970, move the World History Explorer to
+live under `projects/world-history/`, and put the site in a shape that
+supports adding further projects later — without breaking the existing
+project or losing its history.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M3-1 | World History Explorer fully relocated to `projects/world-history/` with no broken internal paths | User request | Met | Whole tree moved as one `git mv` commit (`121b4ff`, git-detected 100% renames); internal relative references between `index.html`/`css/`/`js/`/`data/` are unaffected since the whole subtree moved together |
+| M3-2 | Root becomes a modest personal landing page (Viking/Nordic/French-themed), not the world-history project | User request | Met | New root `index.html` + `css/site.css`: navy/forest-green ground, gold/bronze accents, serif display headings, CSS-only knotwork divider, user's verbatim bio copy |
+| M3-3 | Root design supports future project expansion | User request | Met | `.project-list`/`.project-card` pattern designed for repeated `<li>` entries; root `README.md` documents adding a `projects/<name>/` directory per new project |
+| M3-4 | Moved project verified functional at its new nested path | Process norm (established Milestone 1/2) | Partial | Local static server + `curl` against `projects/world-history/`, `css/history.css`, `js/app.js`, `data/boxes.json` (independently reproduced by the Milestone 3 path/link-integrity council reviewer); `python3 tools/validate_data.py` run from `projects/world-history/` (671 warnings, 0 errors, unchanged — independently reproduced); a Node `loadAllData()` run against the moved JSON was also performed (198/83/390/89 rows, unchanged) but, like the Milestone 2 runtime checks (see M2-9, ISSUE-009), was not captured as a committed, repeatable test file — downgraded from Met to Partial for this sub-claim during Milestone 3 reconciliation |
+| M3-5 | `ISSUES.md`/`TRACEABILITY.md` kept shared at repository root, one continuous history | User request (explicit choice over per-project split) | Met | Neither file moved; both got a "Path note" explaining pre-Milestone-3 entries reference now-superseded root-relative paths |
+| M3-6 | `AGENTS.md`/`README.md` updated to describe the new structure | Process norm (docs must match reality) | Met | `AGENTS.md` gained a "Repository structure" section and updated paths throughout; root `README.md` rewritten for the personal-site framing; old `README.md` moved to `projects/world-history/README.md` with a historical note added |
+| M3-7 | No production backend/DB/auth/API keys introduced | AGENTS.md § Project intent | Met | Restructure introduced only static HTML/CSS and doc changes |
+
+### Milestone 3 council review
+
+Reviewed 2026-09-06 against commit `ce8b234`: path & link integrity PASS,
+static-site architecture/constraints & accessibility PASS_WITH_MINOR_ISSUES,
+process & documentation consistency PASS_WITH_MINOR_ISSUES. No gatekeeper
+findings; a missing project-card heading and a missing font preconnect were
+fixed inline, stale `README.md` section citations were addressed by
+extending the Path note above, and M3-4 was downgraded to Partial to match
+its actual evidence — see `ISSUES.md` § Milestone council reviews. Merged to
+`main`.
+
+## Milestone 4 — Plotly alluvial prototype (Phase 3)
+
+Goal (`docs/IMPLEMENTATION_PLAN.md` Phase 3): create a minimal `Links` table
+for a small subset and a Sankey/alluvial view over it, with nodes ordered
+chronologically, clickable links, selected-node-updates-inspector, and the
+page remaining static.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M4-1 | Minimal `Links` table for a chosen subset | IMPLEMENTATION_PLAN.md Phase 3 | Met | 7-row Links sheet added to the workbook covering the Mediterranean/Europe candidate list (all 9 named boxes: Roman Empire, Western Roman Empire, Byzantine Empire, Frankish Kingdom, West Francia, Kingdom of France, East Francia, Holy Roman Empire, Ottoman Empire); China cluster deliberately left for a later pass (see ISSUE-004 note) |
+| M4-2 | `Links` fields match `DATA_MODEL.md` §5 | docs/DATA_MODEL.md | Met | `link_id`, `source_box_id`, `target_box_id`, `year`, `relation_type`, `weight_basis`, `confidence`, `source_url`, `notes` all present; `relation_type` drawn from the recommended vocabulary |
+| M4-3 | Build/validation extended to cover `Links` | docs/DATA_MODEL.md §8, IMPLEMENTATION_PLAN.md Phase 1 | Met | `validate_links()` in `tools/wh_data.py`: checks `link_id` uniqueness, source/target FK existence against `Boxes`, malformed year, `relation_type` membership (classified as ERROR, not the file's usual WARNING-for-vocabulary default, per Phase 1's explicit "fails on unknown relation types"); year-outside-combined-span is a WARNING. `build_data.py` writes `data/links.json`. Verified: clean run unchanged at 671 warnings/0 errors (Links adds none); a deliberately corrupted `relation_type` and a broken FK were each independently confirmed to block the build (ERROR, exit 1, no output written) |
+| M4-4 | M1-6 ("fails on unknown relation types"), previously Not started, now actually testable | IMPLEMENTATION_PLAN.md Phase 1 | Met | See M4-3; M1-6 above should be read as superseded by this row now that `Links` exists |
+| M4-5 | Nodes ordered chronologically | IMPLEMENTATION_PLAN.md Phase 3 acceptance criteria | Met | `buildSankeyFigure()` in `js/sankey.js` derives node `x` from `start_year` (clamped `[0.02, 0.98]`) and passes `arrangement: "fixed"` to Plotly, which strictly enforces the given coordinates instead of auto-laying-out nodes (AGENTS.md § Visualization semantics forbids auto-reordering); verified via a Node unit test against real generated data confirming monotonic x-ordering |
+| M4-6 | Links clickable | IMPLEMENTATION_PLAN.md Phase 3 acceptance criteria | Partial | `renderSankey()` wires a `plotly_click` handler that distinguishes link clicks (`point.source`/`point.target` present) from node clicks and calls `onSelectLink`/`onSelectBox` accordingly; the pure event-routing logic and `js/app.js` wiring were verified. A real, independently-verified click path also exists via the `#alluvial-list` keyboard/AT alternative (see M4-11), which calls the identical `onSelectLink`/store code and was confirmed end-to-end in the fake-DOM harness. Still Partial because the Plotly chart's own `plotly_click` firing on a real rendered SVG could not be exercised in this environment (no browser) — see M4-8 |
+| M4-7 | Selected node/link updates inspector | IMPLEMENTATION_PLAN.md Phase 3 acceptance criteria | Met | `js/app.js`: `onSelectBox`/`onSelectLink` callbacks set `selectedBoxId`/`selectedLinkId` (mutually exclusive) on the shared store; `renderInspector` branches to `renderLinkInspector` when a link is selected, showing source → target, year, relation type, confidence, notes, source URL. Verified end-to-end for both the box-click path and the link-click path (via `#alluvial-list`, see M4-11) in the fake-DOM harness — this row covers the store/render logic itself, which is fully exercised regardless of which UI element triggers it (chart vs. fallback list); the *chart's own* click-firing is M4-6's remaining caveat |
+| M4-8 | Page remains static (no backend, no build step at runtime) | IMPLEMENTATION_PLAN.md Phase 3 acceptance criteria, AGENTS.md § Project intent | Partial | Plotly loaded via a pinned-version CDN `<script>` (`cdn.plot.ly/plotly-2.35.2.min.js`, reachability verified with `curl -I`); `renderSankey()` call in `main()` is `await`ed inside a try/catch (covering both a synchronous throw and an async `Plotly.newPlot` rejection) so a CDN/offline failure degrades to a text fallback rather than breaking the rest of the page. `links.json` itself is now fetched separately from the required tables (see M4-12) so even a broken/missing Links file can't take down the box list/inspector/filter either. Verified via a Node fake-DOM harness (fetch redirected to a local static server, deliberately no `window.Plotly` to exercise the fallback path): data loads, summary renders, 198 boxes render, region filter (13 options) narrows the list, box click and `#alluvial-list` link click both populate the inspector correctly, filter change resets it, and the alluvial container shows the expected caught fallback message. Marked Partial because this environment has no real browser to confirm actual Plotly chart rendering or genuine `plotly_click` firing — the fallback path and all non-Plotly wiring are the parts that are Met |
+| M4-9 | Accessible alternative for a chart with no native text alternative | AGENTS.md § accessibility | Met | `<div id="alluvial" role="img" aria-label="...">` plus `aria-describedby` pointing at a visually-hidden, keyboard-focusable `#alluvial-list` of real `<button>`s (one per link: source → target, year, relation type) that call the same `onSelectLink` path as a chart click. Added during Milestone 4 council reconciliation after the architecture/accessibility reviewer noted the original `role="img"`/`aria-label`-only treatment gave AT/keyboard users no way to browse or select individual links, unlike the box list's real `<button>` pattern (M2-7). `.visually-hidden:focus-within` (`css/history.css`) makes a focused item visible rather than only technically present in the DOM. Verified via the fake-DOM harness: 7 items render, and simulating a click on the first one correctly populates the inspector. Ribbon-width caveat (equal-weight placeholder, not population-based) stated in visible text above the chart too, not just the aria-label |
+| M4-10 | No production backend/DB/auth/API keys introduced | AGENTS.md § Project intent | Met | Phase 3 added only a workbook sheet, Python validation code, generated JSON, and static JS/CSS/HTML; the Plotly CDN script is a static asset load, not a backend dependency |
+| M4-11 | Chart theme consistency and defensive-coding gaps closed during reconciliation | Milestone 4 architecture/accessibility council review | Met | Three findings fixed inline: (1) `renderSankey()` now reads `--bg`/`--fg` off `:root` via `getComputedStyle` and sets `paper_bgcolor`/`plot_bgcolor`/`font.color` so the chart matches the page's light/dark theme instead of always rendering an opaque white rectangle; (2) `buildSankeyFigure()` guards the case where no referenced box has a numeric `start_year` — an empty `years` array previously produced `Math.min()`/`Math.max()` of `+Infinity`/`-Infinity`, and `-Infinity || 1` still evaluates to `-Infinity` (truthy in JS), silently yielding `NaN` node x-positions; now falls back to `0`/`0` when the array is empty; (3) `renderSankey()` is now `async` and its caller `await`s it, so an asynchronous `Plotly.newPlot` rejection is caught by `js/app.js`'s try/catch instead of becoming an unhandled promise rejection |
+| M4-12 | `links.json` load failure isolated from the required-data load | Milestone 4 architecture/accessibility council review | Met | `js/data.js`'s `loadAllData()` previously fetched `links.json` in the same `Promise.all` as `boxes`/`seais`/`population`/`regions`, so a single broken/missing Links file would reject the whole call and show "Failed to load data," taking down the box list/inspector/filter too. Split into required (`FILES`, hard-fails) and optional (`OPTIONAL_FILES`, catches and defaults to `[]` with a `console.warn`) — matching the graceful-degradation principle already established for the Plotly-load failure itself (M4-8) |
+
+### Milestone 4 council review
+
+Reviewed 2026-09-06 against commit `65f38ab` (branch `feature/alluvial-prototype`),
+three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data integrity | PASS_WITH_MINOR_ISSUES |
+| Static-site architecture/constraints & accessibility | PASS_WITH_MINOR_ISSUES |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No gatekeeper findings. Fixed inline: a real accessibility gap (the Plotly
+widget alone gave AT/keyboard users no way to browse or select a link —
+added the `#alluvial-list` keyboard-focusable fallback, M4-9); a real
+theme-consistency bug (Plotly chart ignoring the page's dark mode, M4-11); a
+real robustness gap (a broken `links.json` could take down the whole page,
+not just the alluvial section, M4-12); a latent `NaN`-node-position edge
+case and an un-awaited `Plotly.newPlot` promise (both M4-11); a misleading
+alluvial-note sentence that read as one chained succession rather than 7
+discrete links (`index.html`); a JSDoc gap (`linksById` missing from
+`loadAllData`'s comment); and an opaque validation error message for a
+missing `relation_type` (now says "missing relation_type" instead of
+"relation_type None not in [...]"). Tabled as new minor issues rather than
+fixed: ISSUE-011 (the `DATA_MODEL.md` §8 "transition year sensible" check is
+a loose union-envelope heuristic, not a real sensibility check). Extended
+existing entries: ISSUE-009 (this is the third milestone where runtime JS
+verification was performed but not committed as a repeatable test file);
+ISSUE-010 (commit granularity improved to 3 commits this milestone, still
+not fully resolved). M4-6/M4-7/M4-8 wording reconciled so a Partial rating
+doesn't overclaim what's actually verified — see `ISSUES.md` § Milestone
+council reviews. Merged to `main`.
+
+## Milestone 5 — D3 timeline prototype (Phase 4)
+
+Goal (`docs/IMPLEMENTATION_PLAN.md` Phase 4): render source-poster-inspired
+boxes from `Boxes` as an SVG timeline, with correct dates, matching colors,
+click selection, date zoom/filter, and SEAI overlay.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M5-1 | Boxes render at correct dates | IMPLEMENTATION_PLAN.md Phase 4 acceptance criteria | Met | `buildTimelineLayout()` in `js/timeline.js` maps each in-view box to `{effectiveStart, end}`; `renderTimeline()` draws a `d3.scaleLinear` x-axis over `[yearStart, yearEnd]` and positions each bar accordingly. Verified by `js/timeline.test.mjs` (committed, run with `node js/timeline.test.mjs`) against the real generated `data/boxes.json`: rows sort ascending by `effectiveStart`, narrowing the year range correctly drops boxes entirely outside it, and region filtering never mixes regions |
+| M5-2 | Colors match source data | IMPLEMENTATION_PLAN.md Phase 4 acceptance criteria | Met | Bar `fill` is `box.color_hex` directly (same field the box list's swatch already uses), falling back to a neutral gray only if a box is missing one |
+| M5-3 | Click selection works | IMPLEMENTATION_PLAN.md Phase 4 acceptance criteria | Partial | `renderTimeline()` wires a click handler on each row's `<g>` calling `onSelectBox(box.box_id)`, which `js/app.js` routes to the same shared `selectedBoxId` the box list uses (mutually exclusive with `selectedLinkId`, matching the existing pattern). The event-routing/store logic was code-reviewed against the identical, already-verified pattern in `js/sankey.js`/`js/app.js`; unlike Milestone 4, this round did not rebuild the fake-DOM harness to simulate an actual click event on a rendered D3 element (cost-conscious tradeoff this milestone — see council review note below), so real click-firing on the rendered SVG is unverified in this environment |
+| M5-4 | Date zoom/filter works | IMPLEMENTATION_PLAN.md Phase 4 acceptance criteria | Met | Plain `<input type="number">` "From year"/"To year" controls (not a D3 brush — chosen specifically because a brush needs real mouse-drag events this no-browser environment can't simulate, whereas a number input's `change` event and resulting `buildTimelineLayout()` output are Node-testable) drive `state.yearStart`/`yearEnd`, with a guard in `js/app.js` rejecting a reversed range (`yearStart > yearEnd`) before it ever reaches the store — `d3.scaleLinear` doesn't throw on one, it just silently draws chronology backwards. Verified by `js/timeline.test.mjs`: narrowing the range to 1900–2000 removes every box whose `end_year` predates it or whose real/effective start postdates it |
+| M5-5 | SEAIs can be overlaid | IMPLEMENTATION_PLAN.md Phase 4 acceptance criteria | Met | `buildTimelineLayout()` builds `seaiMarkers` from `seaisByBoxId`, filtered to the current year range and gated on `state.showSeais` (wired to a checkbox); `renderTimeline()` draws each as a `d3.symbolDiamond` path — a distinct shape, not just a color dot, per AGENTS.md's "color isn't the sole encoding." Verified by `js/timeline.test.mjs`: `showSeais:false` yields zero markers, `showSeais:true` yields a nonempty set, and every marker's year falls within the current domain |
+| M5-6 | ISSUE-005 boxes (no legible start date) don't get a fabricated coordinate | AGENTS.md § Historical-data discipline; docs/STATUS.md limitation #2 | Met | The 6 null-`start_year` boxes get `approxStart: true` and an `effectiveStart` pinned to the current view's left edge (`state.yearStart`), not an invented year; `renderTimeline()` draws these with a dashed (`stroke-dasharray`) stroke — the whole bar's outline, not literally just its left edge (an SVG `<rect>` doesn't support per-side dashing without extra path work). Verified by `js/timeline.test.mjs`: exactly the 6 known ISSUE-005 boxes (`US_INDIG`, `CA_INDIG`, `AR_INDIG`, `AU_INDIG`, `UK_CELTIC`, `JP_JOMON`) carry `approxStart`, all six clamp to `domainStart`, and all six correctly drop out once the visible range starts after their real `end_year` (confirmed with a 1900–2000 window; their actual `end_year`s range from **-300** (`JP_JOMON`) to 1788 (`AU_INDIG`), not 43–1788 as an earlier draft of this row incorrectly stated) |
+| M5-7 | Page remains static; D3 CDN failure degrades gracefully | IMPLEMENTATION_PLAN.md Phase 4, AGENTS.md § Project intent | Partial | D3 loaded via a pinned-version CDN `<script>` (`cdnjs.cloudflare.com/.../d3/7.9.0/d3.min.js`, reachability verified with `curl -I`); `renderTimelineView()` in `js/app.js` wraps `renderTimeline()` in a plain synchronous try/catch (simpler than the Sankey pattern, M4-8, since `renderTimeline()` has no promises to await) so a missing `window.d3` shows a text fallback instead of breaking the rest of the page. `buildTimelineLayout()` itself has no D3/DOM dependency at all and is directly unit-tested by `js/timeline.test.mjs`. Marked Partial for the same reason as M4-8: no real browser in this environment to confirm actual D3 SVG rendering or genuine click-firing |
+| M5-8 | No independent hidden-list fallback for the timeline chart (deliberate, documented) | AGENTS.md § Accessibility | Met | Unlike `#alluvial-list` (M4-9), the timeline intentionally has no hidden-button mirror of its own: `js/app.js`'s `filteredBoxes()` (box list) filters only by region, while `buildTimelineLayout()` filters by region *and* year range, so the box list is always a superset of what the timeline draws for any filter combination — every box shown here is already in the box list, which is fully keyboard-operable and drives the identical `selectedBoxId`. `#timeline` still carries `role="img"`/`aria-label`, and both `index.html`'s visible `.timeline-note` and this table's reasoning state the justification explicitly, so the omission reads as a decision, not an oversight |
+| M5-9 | No production backend/DB/auth/API keys introduced | AGENTS.md § Project intent | Met | Phase 4 added only static JS/CSS/HTML, a pinned CDN script load, and a `package.json` (`{"type":"module"}`, needed only so Node can run `js/timeline.test.mjs` — it changes nothing about how the browser loads the site) |
+
+### Milestone 5 council review
+
+Reviewed against commits `d80728f`/`212409b` (branch `feature/timeline-view`),
+three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Data / content integrity | PASS_WITH_MINOR_ISSUES |
+| Architecture / static-site constraints & accessibility | PASS_WITH_MINOR_ISSUES |
+| Process & documentation consistency | PASS_WITH_MINOR_ISSUES |
+
+No lens found a data-corruption or accessibility gatekeeper defect; the process
+lens flagged two gatekeepers, both about this document and `ISSUES.md`
+disagreeing with themselves, and both fixed inline below rather than tabled:
+
+- **This table's own "v0.1 definition of done" section still said V1-4
+  ("Simple timeline") was "Not started"** in the same commit that added this
+  Milestone 5 section claiming M5-1 "Met" — fixed by superseding V1-4 below,
+  the same way V1-3 was updated after Milestone 4.
+- **ISSUE-009 (no committed test suite for `js/`) was not extended for what
+  would have been its 4th recurrence** — this time actually fixed rather than
+  re-tabled: `js/timeline.test.mjs` is now a committed, repeatable test for
+  `buildTimelineLayout()` (run with `node js/timeline.test.mjs`; a
+  `package.json` with `"type": "module"` was added so Node can load it and
+  `./timeline.js` directly, no scratch-copy workaround needed). This closes
+  the gap for `timeline.js` specifically — `sankey.js`, `app.js`, `data.js`,
+  and `state.js` remain uncovered, so ISSUE-009 stays open with a note
+  rather than resolved outright. `renderTimeline()`'s actual D3/DOM behavior
+  and real click-firing are still unverified in this no-browser environment
+  (see M5-3/M5-7 above) — the new test only covers the pure half.
+
+Also fixed inline (real code changes, not just tabled):
+- **Reversed year-range bug** (architecture finding): setting "From year" >
+  "To year" didn't crash, but `d3.scaleLinear` silently drew the axis and
+  every bar's chronology right-to-left with no warning — a real, if
+  non-crashing, violation of AGENTS.md's "chronology must remain
+  semantically correct." `js/app.js`'s year-input handlers now reject (and
+  visually revert) a change that would put `yearStart` past `yearEnd` or
+  vice versa, before it ever reaches the store.
+- **Dead SEAI tooltip** (architecture finding): `.seai-marker`'s
+  `pointer-events: none` in `css/history.css` meant the diamond's `<title>`
+  tooltip (added in `renderTimeline()`) could never actually receive a
+  hover. Removed the `pointer-events: none` rule.
+- **Wrong evidence numbers and citations** (data-integrity and process
+  findings, both independently caught the same errors): M5-6's stated
+  `end_year` range for the six ISSUE-005 boxes ("43–1788") omitted
+  `JP_JOMON`'s -300 and its "dashed left edge" description overstated what
+  the CSS actually draws; its `AGENTS.md` citation ("§ data honesty") didn't
+  match any real heading. All three corrected above.
+- **Imprecise code comment** (data-integrity finding): `js/timeline.js`'s
+  comment describing how many SEAIs lack a numeric year said "a handful";
+  the real dataset has exactly one. Corrected.
+
+Tabled as new minor issues (not gatekeepers): **ISSUE-012** (no resize
+re-render for the timeline SVG, unlike the Sankey diagram's
+`responsive: true`; a handful of prehistoric-landmark SEAIs whose real year
+predates their parent box's own span by millennia can visually detach from
+their row if a user widens "From year" far enough to bring them into view).
+Also updated inline: `ISSUE-005`/`ISSUE-003` now note this milestone's use
+of them (matching the existing `ISSUE-004` pattern); `ISSUE-010` notes
+Milestone 5 landed as 2 commits, back from Milestone 4's 3. Milestone
+approved to merge to `main`. See `ISSUES.md` § Milestone council reviews for
+the full write-up (also backfilled there: a Milestone 4 section that should
+have existed already but didn't, caught during this review).
+
+## Milestone 6 — Cross-panel selection sync (Phase 5)
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| M6-1 | Selecting a box anywhere (box list, Sankey node, or timeline bar) sets the same shared `selectedBoxId`, reflected in every panel (inspector, box list, timeline bar outline, Sankey node outline) | IMPLEMENTATION_PLAN.md Phase 5: "Selecting one entity anywhere should update every panel" | Partial | `js/app.js`'s `store.subscribe` callback re-runs `renderList`/`renderInspector`/`renderTimelineView`/`renderSankeySelection` on every state change; `js/sankey.js`'s `applySankeySelection` outlines the matching node via `Plotly.restyle`. Code-reviewed against the identical, already-verified pattern from Milestones 4/5; no browser in this environment to confirm the actual rendered outline, same caveat as M5-3/M5-7 |
+| M6-2 | Selecting a link anywhere (alluvial-list button, Sankey link) sets shared `selectedLinkId`, reflected in inspector, alluvial-list `.selected`/`aria-pressed`, Sankey link color + endpoint node outline, and the timeline's two endpoint boxes (`.link-endpoint`) | Same | Partial | `js/app.js`'s `renderAlluvialListSelection`/`renderTimelineView` (resolves `data.linksById.get(selectedLinkId)` to a `Set` of endpoint `box_id`s, passed to `renderTimeline` as `state.linkHighlightBoxIds`); `js/sankey.js`'s `computeSankeyHighlight` (outlines the selected link's two endpoint nodes, added during council reconciliation — see M6-7). Same DOM-rendering caveat as M6-1 |
+| M6-3 | Sankey selection sync doesn't re-register the `plotly_click` handler on every selection change | Avoids a real bug class: N re-renders would fire a click N times | Met | `applySankeySelection` uses `Plotly.restyle` (updates trace styling only), never `Plotly.newPlot`; the click handler stays the one bound once in `renderSankey`. Confirmed by code inspection — `renderSankey`/`applySankeySelection` are separate exported functions, the latter never calling the former |
+| M6-4 | The selection→style computation is a pure, Node-testable function, matching the existing `buildSankeyFigure`/`buildTimelineLayout` split | Project convention (see M5-1's evidence) | Met | `computeSankeyHighlight(links, boxIds, state, colors)` in `js/sankey.js` has no Plotly/DOM dependency; `applySankeySelection` is now a thin wrapper reading CSS custom properties and calling `Plotly.restyle`. Verified by new committed `js/sankey.test.mjs` (run with `node js/sankey.test.mjs`) — 23 assertions, all passing, also covering `buildSankeyFigure` (Phase 3, previously untested) |
+| M6-5 | A `box_id`/`link_id` not present in the Sankey's 7-link subset (e.g. selected via the box list) highlights nothing, rather than throwing or mis-highlighting | Correctness / defensive handling | Met | `js/sankey.test.mjs`: "unknown selectedBoxId/selectedLinkId highlights nothing" assertions pass against real `data/links.json` |
+| M6-6 | Deep-link URL query params (`?box=BYZANTINE&year=537`, IMPLEMENTATION_PLAN.md Phase 5's own example) | IMPLEMENTATION_PLAN.md Phase 5, explicitly framed there as "Possible future deep link" | Deferred | Explicit scope decision, not an oversight: the plan's own wording marks it as a future item, not a Phase 5 acceptance criterion. Not implemented this milestone |
+| M6-7 | New selection UI doesn't use color as the only cue | AGENTS.md § Accessibility ("color isn't the sole encoding") | Met | `#alluvial-list button.selected` mirrors `.box-item.selected`'s existing treatment: background + bold + a leading checkmark (`::before`), not a color change alone; the timeline's `.link-endpoint` stroke is a distinct outline from `.approx-start`'s dashed one, and explicitly resets `stroke-dasharray` so the two cues stay distinguishable even on a box that's both. Originally missed for the Sankey diagram itself — a selected link's ribbon was color-only (`computeSankeyHighlight`'s `linkColor`, no other channel on a Plotly Sankey link) — flagged as a council-review gatekeeper finding and fixed during reconciliation: a selected link now also outlines its two endpoint nodes via `node.line` (the same mechanism a selected box already used), verified by `js/sankey.test.mjs`'s "endpoint nodes are outlined" assertions |
+| M6-8 | Semantic-zoom timescale requirement folded into a development phase and recorded in traceability | User instruction, 2026-09-07: "fold that into one of the development phases... add the requirement to our traceability file" | Met | `docs/IMPLEMENTATION_PLAN.md` new "Phase 5.5" section (ordered before Phase 6); TS-1..TS-11, at the time documentation only, not yet implemented — see "Milestone 7 — Semantic zoom time scale (Phase 5.5)" below for the implementation and updated status |
+| M6-9 | No production backend/DB/auth/API keys introduced | AGENTS.md § Project intent | Met | This milestone changed only static JS/CSS/HTML/Markdown; no new dependency, network call, or CDN source beyond the two already in use (`cdn.plot.ly`, `cdnjs.cloudflare.com/.../d3`) |
+
+### Milestone 6 council review
+
+Reviewed against commit `6e5681a` (branch `feature/shared-interaction`),
+three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Correctness & data-fidelity | PASS |
+| Accessibility & UX | PASS_WITH_MINOR_ISSUES |
+| Architecture & docs/process | PASS_WITH_MINOR_ISSUES |
+
+Two gatekeeper findings, both fixed inline before merge:
+- **Sankey selected-link was color-only** (accessibility gatekeeper): with
+  a link selected, `computeSankeyHighlight()` colored its ribbon `accent`
+  but forced every node's outline to 0 width — a pure color-only encoding,
+  violating AGENTS.md's "color isn't the sole encoding" (and M6-7's table
+  row above had claimed "Met" without disclosing the gap). Fixed by having
+  `computeSankeyHighlight()` also outline the selected link's two endpoint
+  nodes via `node.line`, the same mechanism a selected box already used.
+  `js/sankey.test.mjs` gained two assertions confirming exactly those two
+  nodes (and nothing else) get outlined.
+- **`ISSUES.md` missing a Milestone 6 note** (architecture gatekeeper):
+  both `js/sankey.test.mjs`'s header comment and M6-4's evidence above
+  point at `ISSUES.md` for ISSUE-009's partial resolution, but ISSUES.md
+  itself hadn't been touched — breaking the pattern set at Milestones 4/5
+  of annotating an issue the moment new test coverage lands. Fixed by
+  adding a "Note (Milestone 6)" to ISSUE-009 (see `ISSUES.md`).
+
+Also fixed inline (minor, not gatekeepers):
+- **Dashed/solid CSS comment inaccuracy** (accessibility finding):
+  `.timeline-bar.link-endpoint`'s comment claimed a solid stroke
+  ("not dashed like `.approx-start`") but never reset
+  `stroke-dasharray`, so a box that was both `.approx-start` and
+  `.link-endpoint` still rendered dashed. Added `stroke-dasharray: none;`
+  to the rule so the comment's claim is actually true.
+- **Status vocabulary didn't list `Deferred`** (architecture finding):
+  the new value used at M6-6 wasn't declared in this file's own
+  status-vocabulary line. Added it, with a parenthetical distinguishing it
+  from `Not started`.
+- **`js/README.md` didn't mention `sankey.test.mjs`** (architecture
+  finding): the parallel `timeline.js` paragraph names its test file
+  explicitly; the `sankey.js` paragraph didn't. Added a sentence naming
+  `computeSankeyHighlight()` and the test file's run command.
+
+Accepted as documented, not further changed (correctness lens, all
+minor): (1) `applySankeySelection()`'s `Plotly.restyle` calls aren't
+awaited/queued — two rapid selections could in principle resolve out of
+order, transiently showing a stale highlight; noted in a code comment
+rather than adding cancellation/queueing machinery, since the store
+re-renders full current state on every `set()` and the gap self-corrects
+on the very next change. (2) A pre-existing asymmetry (toggling a box off
+in the box list doesn't toggle other panels' display off the same way) is
+out of scope for this milestone, left as-is. (3) ISSUE-005's empty-years
+guard remains untested against a real empty-subset case — low-priority,
+left untested.
+
+No new issue filed this milestone. `ISSUE-009` gained a Milestone 6 note
+(second module with committed coverage); `ISSUE-010`/`ISSUE-003` unaffected.
+Milestone approved to merge to `main`. See `ISSUES.md` § Milestone council
+reviews for the corresponding entry there.
+
+## Milestone 7 — Semantic zoom time scale (Phase 5.5)
+
+Requirement captured 2026-09-07 (user-authored `docs/timescaleRequirement.md`),
+folded into `docs/IMPLEMENTATION_PLAN.md` as "Phase 5.5" during Milestone 6,
+now implemented: a new pure module (`js/timescale.js`) plus its use as the
+single shared x-position source for both the timeline (Phase 4) and the
+Sankey diagram (Phase 3), and a new "Time compression" slider control.
+
+| Req | Requirement | Source | Status | Evidence |
+|---|---|---|---|---|
+| TS-1 | Nonlinear "semantic zoom" year→x mapping: `p = 1 / (1 + (M/3000) * 2^s)`, `x = 1 - (a/M)^p` | docs/timescaleRequirement.md § Core Mapping | Met | `js/timescale.js`'s `semanticTimeScale()` implements exactly this formula (the multiplicative form, not the additive one the doc warns against); `js/timescale.test.mjs`'s "Zoom behavior" assertions confirm `M=3000,s=0 → p=0.5` and `M→0 → p→1` |
+| TS-2 | Boundary conditions: `yearToX(tMin) == 0`, `yearToX(tMax) == 1` | docs/timescaleRequirement.md § Validation | Met | `js/timescale.test.mjs` "Boundary conditions" — exact equality at all 5 tested `s` values |
+| TS-3 | Monotonic for all `t1 < t2`, any valid `M > 0`, `s in [-2, 2]` | docs/timescaleRequirement.md § Validation | Met | `js/timescale.test.mjs` "Monotonicity" sweeps 5 window sizes (including a near-degenerate one) × 6 scaler values × years both inside and outside `[tMin, tMax]` (needed since `js/timeline.js`'s `xClamped` relies on the scale not blowing up for out-of-domain years) |
+| TS-4 | Inverse transform (`xToYear`) round-trips within float tolerance | docs/timescaleRequirement.md § Implementation Guidance / Validation | Met | `js/timescale.test.mjs` "Round trip" — 11 representative years including two outside `[tMin, tMax]`, tolerance `1e-6` |
+| TS-5 | Reusable `semanticTimeScale({tMin, tMax, scaler})` module, not baked into one view's rendering code | docs/timescaleRequirement.md § Implementation Guidance | Met | `js/timescale.js` has zero D3/DOM/Plotly imports; both `js/timeline.js` and `js/sankey.js` import and call it independently |
+| TS-6 | Shared scale: every time-based element in a view (box start/end, SEAIs, event markers, succession transitions, Sankey/alluvial node x, population knot points, ticks) uses the same transform — no mixed linear/semantic placement within one view | docs/timescaleRequirement.md § Shared Scale | Partial | `js/timeline.js`'s `buildTimelineLayout()` builds one `scale` instance and uses it for box bars, SEAI markers, and axis ticks alike; `js/sankey.js`'s `computeSankeyNodeX()` builds an equivalent instance from the same `state.yearStart/yearEnd/timeScale`, so Sankey node x and the timeline agree. Population knot points aren't part of this (Phase 6 doesn't exist yet — `Population` is still a 0%-filled scaffold, ISSUE-003), so that element of the list is not yet applicable, not unmet |
+| TS-7 | Coordinate stability: mapping depends only on `[tMin, tMax, s]`, never on SEAI/box/population filtering or event density | docs/timescaleRequirement.md § Coordinate Stability | Met | `semanticTimeScale()`'s signature has no other inputs; `js/timescale.test.mjs` "Coordinate stability" confirms two instances built from identical `[tMin, tMax, s]` agree exactly |
+| TS-8 | User-adjustable slider, range `[-2, 2]`, default `0`, labeled for effect (e.g. "Ancient detail ↔ Recent detail") — raw exponent not exposed | docs/timescaleRequirement.md § User Control | Met | `index.html`'s `#time-scale` (`type="range" min="-2" max="2" step="0.1" value="0"`), labeled "Time compression (ancient detail ↔ recent detail)"; `js/state.js`'s `timeScale: 0` default; only the slider's own `s` value is shown, never `p`/exponent |
+| TS-9 | Ticks generated in calendar time first, then transformed (not evenly spaced screen ticks reverse-mapped); density adapts to zoom level | docs/timescaleRequirement.md § Tick Generation | Met | `js/timescale.js`'s `timeTicks(tMin, tMax)` picks candidate tick *years* from a fixed interval list before any x-transform is applied; `js/timeline.js`'s `renderTimeline()` only ever calls `scale.yearToX()` on those years, never the reverse. Interval chosen from `span / 10`, so density adapts as the visible range narrows |
+| TS-10 | Updates interactively (slider drag, zoom) without a full page reload; cheap enough to recompute continuously during drag | docs/timescaleRequirement.md § Performance | Met | Slider bound to the `input` event (fires continuously while dragging), not `change`; timeline redraws its SVG per state change (same full-redraw approach as the pre-existing region/year filters, 198-box dataset), Sankey uses `Plotly.restyle` (no full re-render) — no page reload in either path |
+| TS-11 | Optional: animate the layout smoothly while zooming | docs/timescaleRequirement.md § Zoom Interaction ("if technically practical") | Deferred | Explicitly framed as optional in the source doc; not attempted this milestone — logged in `ISSUES.md` |
+
+### Milestone 7 council review
+
+Reviewed commit `887f483` (branch `feature/semantic-zoom-scale`) vs. `main`
+at `2df28c3`, three lenses:
+
+| Reviewer | Verdict |
+|---|---|
+| Correctness & data-fidelity | PASS |
+| Accessibility & UX | PASS_WITH_MINOR_ISSUES |
+| Architecture & docs/process | PASS |
+
+One gatekeeper finding, fixed inline before merge: **tick label "0 CE"**
+(accessibility gatekeeper) — `js/timeline.js`'s `formatTickYear` rendered a
+tick landing on calendar year 0 as "0 CE", but `docs/DATA_MODEL.md`
+documents that this dataset has no historical year zero, and the app's own
+default `-3000..2026` view produces exactly such a tick (TS-9's "density
+adapts to zoom level" claim was accurate, but didn't account for this
+label being wrong at the *default* zoom). Fixed at the source: `timeTicks()`
+now excludes an exact-0 tick candidate (new assertion in
+`timescale.test.mjs`); `formatTickYear` also independently guards year 0
+(and the `-0` `Math.round` can produce for a fractional year) for any
+future reuse as a hover/inspector label.
+
+Also fixed inline (minor, not gatekeepers):
+- `js/sankey.test.mjs` didn't exercise `computeSankeyNodeX`'s null-`start_year`
+  fallback (ISSUE-005) — added a synthetic-box test case.
+- `js/timeline.js`'s tick rendering recomputed `scale.yearToX(year)` a
+  second time per tick instead of reusing the `x` already computed on each
+  `layout.ticks` entry — simplified to reuse it.
+
+Tabled (see `ISSUES.md`): ISSUE-013 (smooth zoom animation, explicitly
+optional per the spec) and new ISSUE-014 (the time-scale slider's `input`
+listener re-renders every panel, not just the ones depending on
+`timeScale` — no debounce/RAF throttle). ISSUE-010 (commit granularity)
+noted as regressed further this milestone (a single commit). Milestone
+approved to merge to `main`.
+
+## v0.1 definition of done (forward-looking; not yet in scope)
+
+Tracked here so later milestones can check items off against `AGENTS.md`'s
+"Definition of done for v0.1" without re-deriving the list.
+
+| Req | Requirement | Status |
+|---|---|---|
+| V1-1 | Runs as a static site | Met (Milestone 2) |
+| V1-2 | Loads generated JSON | Met (Milestone 2) |
+| V1-3 | Interactive chronological Sankey/alluvial subset | Partial (Milestone 4, small 7-link Mediterranean/Europe subset; see M4-6/M4-8 caveats) |
+| V1-4 | Simple timeline | Partial (Milestone 5; a first D3 Gantt-style bar-per-box timeline exists with click selection, year-range filter, and SEAI overlay — see M5-1..M5-9 — but not yet the poster's own lane/segment geometry or population-based width) |
+| V1-5 | Select a historical box | Met (Milestone 2 box-list; Milestone 4 adds alluvial node/link selection for the Links subset, see M4-6) |
+| V1-6 | Updates an inspector | Met (Milestone 2) |
+| V1-7 | At least one region filter | Met (Milestone 2) |
+| V1-8 | Deployable to GitHub Pages | Met (live since Milestone 0; Milestone 2 content not yet merged to `main`) |
diff --git a/css/site.css b/css/site.css
new file mode 100644
index 0000000..aaad80d
--- /dev/null
+++ b/css/site.css
@@ -0,0 +1,216 @@
+/* Root landing page — Nordic/Viking/French-inspired, CSS-only (no image
+   assets: keeps this a true zero-dependency static page, matching
+   AGENTS.md's "prefer plain HTML/CSS" principle). */
+
+:root {
+  --ink: #1b2430;
+  --paper: #f4f1e8;
+  --panel: #ffffff;
+  --rule: #c9c0a8;
+  --navy: #1f3350;
+  --forest: #2f4a3c;
+  --gold: #a97c34;
+  --bronze: #8a5a2b;
+  --muted: #5b6472;
+  --link: var(--navy);
+  --link-visited: var(--forest);
+  --font-display: "Cinzel", "Trajan Pro", Georgia, serif;
+  --font-body: "EB Garamond", Garamond, Georgia, serif;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    --ink: #e8e4d8;
+    --paper: #14181f;
+    --panel: #1b212b;
+    --rule: #3a4250;
+    --navy: #7fa0c9;
+    --forest: #7fb89a;
+    --gold: #d4a24e;
+    --bronze: #c98a52;
+    --muted: #9aa3b0;
+    --link: var(--gold);
+    --link-visited: var(--forest);
+  }
+}
+
+* {
+  box-sizing: border-box;
+}
+
+body {
+  margin: 0;
+  background: var(--paper);
+  color: var(--ink);
+  font-family: var(--font-body);
+  font-size: 1.125rem;
+  line-height: 1.6;
+}
+
+.hall {
+  max-width: 42rem;
+  margin: 0 auto;
+  padding: 3rem 1.5rem 4rem;
+}
+
+.hero {
+  text-align: center;
+}
+
+.kicker {
+  margin: 0;
+  font-family: var(--font-display);
+  font-size: 0.85rem;
+  letter-spacing: 0.35em;
+  text-transform: uppercase;
+  color: var(--bronze);
+}
+
+.hero h1 {
+  margin: 0.5rem 0 0.25rem;
+  font-family: var(--font-display);
+  font-weight: 700;
+  font-size: clamp(1.75rem, 5vw, 2.75rem);
+  color: var(--navy);
+  line-height: 1.2;
+}
+
+.tagline {
+  margin: 0;
+  color: var(--muted);
+  font-style: italic;
+}
+
+/* CSS-only knotwork/rune-style divider: a repeating interlace pattern drawn
+   with a conic-gradient, no image asset required. */
+.knotwork {
+  border: 0;
+  height: 0.5rem;
+  margin: 2rem auto;
+  max-width: 16rem;
+  background-image: repeating-linear-gradient(
+    135deg,
+    var(--gold) 0 0.5rem,
+    transparent 0.5rem 1rem
+  ),
+  repeating-linear-gradient(
+    45deg,
+    var(--forest) 0 0.5rem,
+    transparent 0.5rem 1rem
+  );
+  background-blend-mode: multiply;
+  opacity: 0.8;
+  border-radius: 999px;
+}
+
+@media (prefers-color-scheme: dark) {
+  .knotwork {
+    background-blend-mode: screen;
+  }
+}
+
+.visually-hidden-heading {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}
+
+main section + section {
+  margin-top: 2.5rem;
+}
+
+main p {
+  margin: 0 0 1rem;
+}
+
+main p:last-child {
+  margin-bottom: 0;
+}
+
+#projects-heading {
+  font-family: var(--font-display);
+  font-size: 1.1rem;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+  color: var(--forest);
+  border-bottom: 1px solid var(--rule);
+  padding-bottom: 0.5rem;
+  margin-bottom: 1rem;
+}
+
+.project-list {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+  display: grid;
+  gap: 1rem;
+}
+
+.project-card {
+  background: var(--panel);
+  border: 1px solid var(--rule);
+  border-left: 3px solid var(--gold);
+  border-radius: 0.25rem;
+  padding: 1rem 1.25rem;
+}
+
+.project-card h3 {
+  margin: 0;
+  font-family: var(--font-display);
+  font-weight: 700;
+  font-size: 1.1rem;
+}
+
+.project-card h3 a {
+  text-decoration: none;
+  color: var(--navy);
+}
+
+.project-card h3 a:visited {
+  color: var(--link-visited);
+}
+
+.project-card h3 a:hover,
+.project-card h3 a:focus-visible {
+  text-decoration: underline;
+}
+
+.project-card > p {
+  margin-top: 0.4rem;
+  color: var(--muted);
+  font-size: 0.95rem;
+}
+
+a {
+  color: var(--link);
+}
+
+a:visited {
+  color: var(--link-visited);
+}
+
+a:focus-visible {
+  outline: 2px solid var(--gold);
+  outline-offset: 2px;
+}
+
+footer {
+  margin-top: 3rem;
+  text-align: center;
+  font-size: 0.9rem;
+}
+
+footer a {
+  text-decoration: none;
+}
+
+footer a:hover,
+footer a:focus-visible {
+  text-decoration: underline;
+}
diff --git a/index.html b/index.html
index efb40bc..fc72d4c 100644
--- a/index.html
+++ b/index.html
@@ -1 +1,65 @@
-Hello cruel World
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>erikson1970</title>
+<meta name="description" content="Personal site of erikson1970 — engineer and technologist working in RF systems, radar, SDR, and embedded computing.">
+<link rel="preconnect" href="https://fonts.googleapis.com">
+<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Cinzel:wght@500;700&family=EB+Garamond:ital,wght@0,400;0,500;1,400&display=swap">
+<link rel="stylesheet" href="css/site.css">
+</head>
+<body>
+  <div class="hall">
+    <header class="hero">
+      <p class="kicker">erikson1970</p>
+      <h1>Part Viking, part sous-chef.</h1>
+      <p class="tagline">Engineer &amp; technologist.</p>
+    </header>
+
+    <hr class="knotwork" aria-hidden="true">
+
+    <main>
+      <section aria-labelledby="about-heading">
+        <h2 id="about-heading" class="visually-hidden-heading">About</h2>
+        <p>
+          erikson1970, part Viking, part sous-chef, is an engineer and
+          technologist with broad interests in RF systems, radar,
+          software-defined radio, phased arrays, embedded computing, and
+          signal processing. He enjoys exploring the intersection of
+          hardware and software, particularly through hands-on
+          experimentation, modeling, prototyping, and open-source tools.
+        </p>
+        <p>
+          His interests also extend to systems engineering, space and
+          sensing technologies, scientific computing, and the history of
+          technology. Outside of engineering, he has a longstanding
+          interest in history, public institutions, gardening, cooking,
+          and practical DIY projects.
+        </p>
+      </section>
+
+      <section aria-labelledby="projects-heading">
+        <h2 id="projects-heading">Projects</h2>
+        <ul class="project-list">
+          <li class="project-card">
+            <h3><a href="projects/world-history/">World History Explorer</a></h3>
+            <p>
+              An interactive, static visualization of world history built
+              from the ChartOrigin <em>Timeline of World History</em>
+              poster &mdash; historical polities, significant events, and
+              (in progress) succession relationships.
+            </p>
+          </li>
+          <!-- Future projects: add another <li class="project-card"> here. -->
+        </ul>
+      </section>
+    </main>
+
+    <footer>
+      <p><a href="https://github.com/erikson1970">github.com/erikson1970</a></p>
+    </footer>
+  </div>
+</body>
+</html>
diff --git a/projects/world-history/README.md b/projects/world-history/README.md
new file mode 100644
index 0000000..d40faff
--- /dev/null
+++ b/projects/world-history/README.md
@@ -0,0 +1,175 @@
+# World History Explorer
+
+## Purpose
+
+This project turns the ChartOrigin **Timeline of World History** poster into a richer, interactive, static web visualization that can be hosted on GitHub Pages.
+
+Canonical visual source:
+
+- https://chartorigin.com/product/timeline-of-world-history/
+
+Lives at `projects/world-history/` within:
+
+- https://github.com/erikson1970/erikson1970.github.io
+
+served at `erikson1970.github.io/projects/world-history/`. (Historical note:
+this project originally occupied the whole repository; see the root
+`README.md`/`AGENTS.md` for the Milestone 3 restructure that moved it here
+alongside a personal landing page and room for future projects.)
+
+## Core idea
+
+The original poster presents historical polities/civilizations as colored boxes arranged vertically through time and horizontally by modern-country alignment.
+
+The project should preserve that basic model, but make it interactive and extensible:
+
+- zoom and pan through time;
+- filter by region/country;
+- click a historical box to inspect details;
+- show significant events / architecture items (SEAIs);
+- vary visual width using population, `log10(population)`, or other transforms;
+- experiment with Sankey/alluvial-style succession flows;
+- eventually support additional regions missing from the original poster.
+
+The project should remain **fully static in production**. No server-side application or database is required.
+
+## Data authority
+
+The Excel workbook is intended to remain the human-editable source of truth.
+
+Current logical tables:
+
+1. `Boxes`
+2. `SEAIs`
+3. `Population`
+4. `Regions`
+
+Proposed next tables:
+
+5. `Links`
+6. `BoxSegments`
+
+The browser should consume generated JSON, not parse Excel directly.
+
+Recommended pipeline:
+
+```text
+Excel workbook
+    ↓
+Python validation/build script
+    ↓
+JSON files
+    ↓
+Static HTML/CSS/JavaScript
+    ↓
+GitHub Pages
+```
+
+## Recommended site structure
+
+```text
+/
+├── index.html
+├── css/
+│   └── history.css
+├── js/
+│   ├── app.js
+│   ├── timeline.js
+│   ├── sankey.js
+│   └── data.js
+├── data/
+│   ├── boxes.json
+│   ├── seais.json
+│   ├── population.json
+│   ├── regions.json
+│   ├── links.json
+│   └── box-segments.json
+├── source/
+│   └── *.xlsx
+├── tools/
+│   ├── build_data.py
+│   └── validate_data.py
+└── docs/
+    ├── STATUS.md
+    ├── DATA_MODEL.md
+    ├── VISUALIZATION.md
+    └── IMPLEMENTATION_PLAN.md
+```
+
+A simpler initial implementation is fine. The important architectural choice is that the site remains static and the generated data remains separate from rendering code.
+
+## Technology direction
+
+### Prototype
+
+Use Plotly first for a quick interactive Sankey/alluvial experiment.
+
+Why:
+
+- fast iteration;
+- good hover behavior;
+- easy static HTML export;
+- Python preprocessing is convenient;
+- useful for learning what the data wants to do.
+
+### Likely final renderer
+
+Use D3 for the primary visualization if Plotly becomes restrictive.
+
+D3 is likely better for:
+
+- exact historical placement along the time axis;
+- custom time-varying widths;
+- linked interactions across multiple views;
+- custom SEAIs and annotations;
+- unusual alluvial / timeline hybrid geometry.
+
+Apache ECharts is also a reasonable intermediate option and may be preferable to Plotly for dashboard-like interaction.
+
+## Initial user experience
+
+A useful first public page would have three synchronized areas:
+
+1. **Main flow view** — Sankey/alluvial representation of historical succession.
+2. **Timeline view** — original-poster-inspired chronological boxes.
+3. **Inspector panel** — selected box details, dates, population, uncertainty, SEAIs, region, Wikipedia link.
+
+Suggested controls:
+
+- region filter;
+- date range;
+- width basis: equal / population / `log10(population)` / square root population;
+- show/hide SEAIs;
+- show/hide uncertainty;
+- show/hide modern-country labels.
+
+## Important modeling principle
+
+A Sankey diagram implies flow, but historical population is not literally conserved from one polity to another.
+
+The intended meaning should be explicit:
+
+> Ribbon width represents the estimated scale of the historical entity at that point in time, not a literal transfer of people.
+
+The preferred terminology is therefore **alluvial history view** or **civilizational flow view**, even if implemented using a Sankey library.
+
+## Current project status
+
+The initial source chart has been transcribed into spreadsheet form.
+
+Current known counts:
+
+- 198 historical boxes;
+- 83 SEAIs;
+  - 30 numbered “Milestones of Civilization”;
+  - 53 labeled landmark / architectural items;
+- 390 seeded population boundary rows;
+- 89 country rows across five added regional groupings.
+
+See `docs/STATUS.md` for details and known limitations.
+
+## Guiding principle
+
+The goal is not to create a definitive universal history ontology on the first pass.
+
+Start with a clean, inspectable, extensible model that supports visualization experiments. Add historical precision incrementally, with sources and uncertainty preserved rather than hidden.
diff --git a/projects/world-history/css/README.md b/projects/world-history/css/README.md
new file mode 100644
index 0000000..a0db8ad
--- /dev/null
+++ b/projects/world-history/css/README.md
@@ -0,0 +1,4 @@
+# css/
+
+Hand-written stylesheets for the static site (no framework/build step assumed
+unless a real need shows up). Planned: `history.css`.
diff --git a/projects/world-history/css/history.css b/projects/world-history/css/history.css
new file mode 100644
index 0000000..17089bb
--- /dev/null
+++ b/projects/world-history/css/history.css
@@ -0,0 +1,311 @@
+/* Minimal styling for the Phase 2 sanity-check UI: a filterable box list and
+   an inspector panel. Deliberately plain -- no framework, no build step (see
+   AGENTS.md "prefer plain HTML, CSS, modular JavaScript"). Layout/visual
+   design for the real timeline/alluvial views comes in later phases. */
+
+:root {
+  color-scheme: light dark;
+  --bg: #ffffff;
+  --fg: #1a1a1a;
+  --muted: #666666;
+  --border: #d8d8d8;
+  --accent: #2456a8;
+  --selected-bg: #eaf1fb;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    --bg: #17191c;
+    --fg: #e8e8e8;
+    --muted: #a0a0a0;
+    --border: #3a3d42;
+    --accent: #6ea6ff;
+    --selected-bg: #1f2a3d;
+  }
+}
+
+* { box-sizing: border-box; }
+
+/* Visible sections still get a real <h2> for screen readers / structure,
+   but the two-panel layout doesn't need it printed on screen. Also used
+   (Phase 3) for a hidden-but-focusable text/button alternative to the
+   Plotly Sankey diagram -- see #alluvial-list in index.html. */
+.visually-hidden,
+.visually-hidden-heading {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}
+/* ...but a focused child (e.g. a keyboard-focused button inside the hidden
+   #alluvial-list) must become visible, or keyboard users lose all focus
+   indication -- AGENTS.md accessibility: keyboard access must be real, not
+   just technically present in the DOM. */
+.visually-hidden:focus-within {
+  position: static;
+  width: auto;
+  height: auto;
+  margin: 0;
+  overflow: visible;
+  clip: auto;
+  white-space: normal;
+}
+
+body {
+  font-family: system-ui, sans-serif;
+  margin: 0;
+  padding: 1.5rem;
+  max-width: 72rem;
+  margin-inline: auto;
+  line-height: 1.5;
+  background: var(--bg);
+  color: var(--fg);
+}
+
+header h1 { margin-bottom: 0.25rem; }
+header .status { color: var(--muted); margin: 0.25rem 0; }
+header .status-error { color: #b3261e; }
+header .summary { color: var(--muted); font-size: 0.9rem; margin: 0.25rem 0 1rem; }
+
+.controls {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  margin-bottom: 1rem;
+}
+.controls label { font-weight: 600; }
+.controls select {
+  font: inherit;
+  padding: 0.3rem 0.5rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: var(--bg);
+  color: var(--fg);
+}
+
+.timeline-section {
+  margin-bottom: 1.5rem;
+}
+.timeline-section h2 {
+  margin-bottom: 0.25rem;
+  font-size: 1.1rem;
+}
+.timeline-note {
+  color: var(--muted);
+  font-size: 0.85rem;
+  margin: 0 0 0.5rem;
+}
+.timeline-controls {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  margin-bottom: 0.5rem;
+  flex-wrap: wrap;
+}
+.timeline-controls label { font-weight: 600; }
+.timeline-controls input[type="number"] {
+  font: inherit;
+  width: 6rem;
+  padding: 0.3rem 0.5rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: var(--bg);
+  color: var(--fg);
+}
+/* Phase 5.5: the semantic-zoom slider (docs/timescaleRequirement.md). Given
+   an explicit width like the number inputs above rather than the browser
+   default (which varies a lot, e.g. Firefox's much wider default), and
+   enough of it to make small drags legible. */
+.timeline-controls input[type="range"] {
+  width: 10rem;
+}
+#timeline {
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  min-height: 120px;
+  max-height: 70vh;
+  overflow: auto;
+}
+.timeline-empty {
+  padding: 0.75rem;
+  color: var(--muted);
+}
+/* D3-drawn SVG content: theme-match the axis, and give bars/markers a
+   real shape/stroke cue in addition to color (AGENTS.md accessibility:
+   color isn't the sole encoding). */
+#timeline .timeline-axis .domain,
+#timeline .timeline-axis .tick line {
+  stroke: var(--border);
+}
+#timeline .timeline-axis .tick text {
+  fill: var(--muted);
+  font-size: 0.7rem;
+}
+#timeline .timeline-bar {
+  stroke: var(--border);
+  stroke-width: 1;
+}
+#timeline .timeline-bar.approx-start {
+  stroke-dasharray: 4 2;
+}
+#timeline .timeline-bar.selected {
+  stroke: var(--accent);
+  stroke-width: 3;
+}
+/* Phase 5: a selected alluvial link highlights its two endpoint boxes here
+   too. Solid (not dashed like .approx-start) so the two cues stay visually
+   distinct even on a box that happens to be both. */
+#timeline .timeline-bar.link-endpoint {
+  stroke: var(--accent);
+  stroke-width: 2;
+  /* Override .approx-start's dasharray explicitly (equal CSS specificity,
+     so source order alone isn't a reliable enough guarantee to leave
+     implicit) -- a box that's both an ISSUE-005 approx-start box and a
+     selected link's endpoint must still read as solid here, or the "solid,
+     not dashed" distinction this class exists for silently stops applying
+     (council review finding). */
+  stroke-dasharray: none;
+}
+#timeline .timeline-row:hover .timeline-bar {
+  opacity: 0.85;
+}
+#timeline .seai-marker {
+  fill: var(--fg);
+  stroke: var(--bg);
+  stroke-width: 1;
+}
+
+.alluvial-section {
+  margin-bottom: 1.5rem;
+}
+.alluvial-section h2 {
+  margin-bottom: 0.25rem;
+  font-size: 1.1rem;
+}
+.alluvial-note {
+  color: var(--muted);
+  font-size: 0.85rem;
+  margin: 0 0 0.5rem;
+}
+#alluvial {
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  min-height: 320px;
+}
+#alluvial-list {
+  list-style: none;
+  margin: 0.5rem 0 0;
+  padding: 0;
+}
+#alluvial-list button {
+  font: inherit;
+  padding: 0.3rem 0.5rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  background: var(--bg);
+  color: var(--fg);
+  cursor: pointer;
+}
+/* Phase 5: mirrors .box-item.selected's treatment (background + bold +
+   leading checkmark, not color alone) so a link selected via the Sankey
+   diagram or elsewhere is visibly marked here too. */
+#alluvial-list button.selected {
+  background: var(--selected-bg);
+  font-weight: 600;
+}
+#alluvial-list button.selected::before {
+  content: "\2713 ";
+  color: var(--accent);
+  font-weight: 700;
+}
+
+.panels {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 1.5rem;
+}
+@media (max-width: 40rem) {
+  .panels { grid-template-columns: 1fr; }
+}
+
+#box-list {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+  max-height: 70vh;
+  overflow-y: auto;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+}
+#box-list li + li { border-top: 1px solid var(--border); }
+.box-empty { padding: 0.75rem; color: var(--muted); }
+
+.box-item {
+  display: flex;
+  align-items: center;
+  gap: 0.6rem;
+  width: 100%;
+  padding: 0.5rem 0.75rem;
+  border: none;
+  background: transparent;
+  color: inherit;
+  font: inherit;
+  text-align: left;
+  cursor: pointer;
+}
+.box-item:hover { background: var(--selected-bg); }
+.box-item:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: -2px;
+}
+.box-item.selected {
+  background: var(--selected-bg);
+  font-weight: 600;
+}
+/* Selection state also carries a text/shape cue (bold + a leading marker via
+   ::before), not just color -- AGENTS.md accessibility: color isn't the sole
+   encoding. */
+.box-item.selected::before {
+  content: "\2713";
+  color: var(--accent);
+  font-weight: 700;
+  width: 1rem;
+  flex: none;
+}
+.box-item:not(.selected)::before {
+  content: "";
+  width: 1rem;
+  flex: none;
+}
+
+.swatch {
+  width: 0.9rem;
+  height: 0.9rem;
+  border-radius: 2px;
+  border: 1px solid rgba(0, 0, 0, 0.25);
+  flex: none;
+}
+
+.box-label { overflow-wrap: anywhere; }
+
+#inspector {
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  padding: 0.75rem 1rem;
+  max-height: 70vh;
+  overflow-y: auto;
+}
+#inspector h2 { margin-top: 0; }
+#inspector ul { margin: 0.25rem 0; padding-left: 1.25rem; }
+
+footer {
+  margin-top: 2rem;
+  color: var(--muted);
+  font-size: 0.85rem;
+}
+footer code { background: rgba(127, 127, 127, 0.15); padding: 0.1rem 0.3rem; border-radius: 3px; }
diff --git a/projects/world-history/data/README.md b/projects/world-history/data/README.md
new file mode 100644
index 0000000..54ab9aa
--- /dev/null
+++ b/projects/world-history/data/README.md
@@ -0,0 +1,19 @@
+# data/
+
+Generated output only. Everything here is produced by `tools/build_data.py`
+from `source/*.xlsx` and must be reproducible from it. Do not hand-edit files
+in this directory — fix the workbook or the build script instead, then
+regenerate:
+
+```
+python3 tools/build_data.py
+```
+
+Current outputs: `boxes.json`, `seais.json`, `population.json`, `regions.json`,
+`links.json`. Later: `box-segments.json` once that table exists in the
+workbook (see `docs/DATA_MODEL.md` #6).
+
+`links.json` (Phase 3, Milestone 4) is a small hand-authored subset — 7 rows
+covering the Roman/Byzantine/Frankish/French/Holy-Roman/Ottoman succession
+chain from `docs/IMPLEMENTATION_PLAN.md`'s "Mediterranean / Europe" Phase 3
+candidate list — not full coverage of every box in `boxes.json`.
diff --git a/projects/world-history/data/boxes.json b/projects/world-history/data/boxes.json
new file mode 100644
index 0000000..1690fd1
--- /dev/null
+++ b/projects/world-history/data/boxes.json
@@ -0,0 +1,3566 @@
+[
+  {
+    "box_id": "US_INDIG",
+    "box_name": "Indigenous Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": null,
+    "end_year": 1607,
+    "start_label": "c. BCE",
+    "end_label": "1607",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "United States",
+    "span_count": 1,
+    "span_start": "United States",
+    "span_end": "United States",
+    "region_group": "Americas",
+    "notes": "The chart prints 'c. BCE' without a legible/visible number at the top of this box.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "US_COLONIAL",
+    "box_name": "Colonial America",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1607,
+    "end_year": 1776,
+    "start_label": "1607",
+    "end_label": "1776",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "United States",
+    "span_count": 1,
+    "span_start": "United States",
+    "span_end": "United States",
+    "region_group": "Americas",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "US_MODERN",
+    "box_name": "United States",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1776,
+    "end_year": 2026,
+    "start_label": "1776",
+    "end_label": "Present",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "United States",
+    "span_count": 1,
+    "span_start": "United States",
+    "span_end": "United States",
+    "region_group": "Americas",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "CA_INDIG",
+    "box_name": "Indigenous Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": null,
+    "end_year": 1608,
+    "start_label": "c. BCE",
+    "end_label": "1608",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Canada",
+    "span_count": 1,
+    "span_start": "Canada",
+    "span_end": "Canada",
+    "region_group": "Americas",
+    "notes": "The chart prints 'c. BCE' without a legible/visible number at the top of this box.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "CA_COLONIAL",
+    "box_name": "Colonial Canada",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1608,
+    "end_year": 1867,
+    "start_label": "1608",
+    "end_label": "1867",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Canada",
+    "span_count": 1,
+    "span_start": "Canada",
+    "span_end": "Canada",
+    "region_group": "Americas",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CA_MODERN",
+    "box_name": "Canada",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1867,
+    "end_year": 2026,
+    "start_label": "1867",
+    "end_label": "Present",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Canada",
+    "span_count": 1,
+    "span_start": "Canada",
+    "span_end": "Canada",
+    "region_group": "Americas",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2000,
+    "end_year": 1521,
+    "start_label": "c. 2000 BCE",
+    "end_label": "1521",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Mexico",
+    "span_count": 1,
+    "span_start": "Mexico",
+    "span_end": "Mexico",
+    "region_group": "Americas",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "LATAM_COLONIAL",
+    "box_name": "Colonial Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1500,
+    "end_year": 1821,
+    "start_label": "1500 / 1521",
+    "end_label": "1816 / 1821",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Mexico; Argentina",
+    "span_count": 2,
+    "span_start": "Mexico",
+    "span_end": "Argentina",
+    "region_group": "Americas",
+    "notes": "Step-shaped shared box: Argentina segment is approximately 1500–1816; Mexico segment 1521–1821.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "MX_MODERN",
+    "box_name": "Mexico",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1821,
+    "end_year": 2026,
+    "start_label": "1821",
+    "end_label": "Present",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Mexico",
+    "span_count": 1,
+    "span_start": "Mexico",
+    "span_end": "Mexico",
+    "region_group": "Americas",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "AR_INDIG",
+    "box_name": "Indigenous Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": null,
+    "end_year": 1500,
+    "start_label": "c. BCE",
+    "end_label": "1500",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Argentina",
+    "span_count": 1,
+    "span_start": "Argentina",
+    "span_end": "Argentina",
+    "region_group": "Americas",
+    "notes": "Mapuche & other Indigenous cultures; top date is printed only as 'c. BCE'.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "AR_MODERN",
+    "box_name": "Argentina",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1816,
+    "end_year": 2026,
+    "start_label": "1816",
+    "end_label": "Present",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Argentina",
+    "span_count": 1,
+    "span_start": "Argentina",
+    "span_end": "Argentina",
+    "region_group": "Americas",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "AU_INDIG",
+    "box_name": "Indigenous Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": null,
+    "end_year": 1788,
+    "start_label": "c. BCE",
+    "end_label": "1788",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Australia",
+    "span_count": 1,
+    "span_start": "Australia",
+    "span_end": "Australia",
+    "region_group": "Oceania",
+    "notes": "Aboriginal and Torres Strait Islander cultures; top date is printed only as 'c. BCE'.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "AU_COLONIAL",
+    "box_name": "Colonial Australia",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1788,
+    "end_year": 1901,
+    "start_label": "1788",
+    "end_label": "1901",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Australia",
+    "span_count": 1,
+    "span_start": "Australia",
+    "span_end": "Australia",
+    "region_group": "Oceania",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AU_MODERN",
+    "box_name": "Australia",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1901,
+    "end_year": 2026,
+    "start_label": "1901",
+    "end_label": "Present",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Australia",
+    "span_count": 1,
+    "span_start": "Australia",
+    "span_end": "Australia",
+    "region_group": "Oceania",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "UK_CELTIC",
+    "box_name": "Celtic Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": null,
+    "end_year": 43,
+    "start_label": "c. BCE",
+    "end_label": "43",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "United Kingdom",
+    "span_count": 1,
+    "span_start": "United Kingdom",
+    "span_end": "United Kingdom",
+    "region_group": "Europe",
+    "notes": "Top date is printed as 'c. BCE' with no legible number in the supplied image.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "UK_SUBROMAN",
+    "box_name": "Sub-Roman Britain",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 410,
+    "end_year": 500,
+    "start_label": "410",
+    "end_label": "500",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "United Kingdom",
+    "span_count": 1,
+    "span_start": "United Kingdom",
+    "span_end": "United Kingdom",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "UK_ANGLOSAXON",
+    "box_name": "Anglo-Saxon Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 500,
+    "end_year": 829,
+    "start_label": "500",
+    "end_label": "829",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "United Kingdom",
+    "span_count": 1,
+    "span_start": "United Kingdom",
+    "span_end": "United Kingdom",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "UK_WESSEX",
+    "box_name": "Wessex Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 829,
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+    "span_end": "United Kingdom",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
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+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "UK_PLANTAGENET",
+    "box_name": "Plantagenet Dynasty",
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+    "span_end": "United Kingdom",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "UK_TUDOR",
+    "box_name": "Tudor Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "region_group": "Europe",
+    "notes": null,
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+  },
+  {
+    "box_id": "UK_STUART",
+    "box_name": "Stuart Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "UK_HANOVER",
+    "box_name": "Hanoverian Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "1714",
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+    "color_name": "red",
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+    "region_group": "Europe",
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+  },
+  {
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+    "box_name": "United Kingdom",
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+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "PT_TRIBES",
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+    "color_name": "orange",
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
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+    "region_group": "Europe",
+    "notes": "The Suebi Kingdom overlays part of the Portuguese/northwestern Iberian portion until 585.",
+    "confidence": "High"
+  },
+  {
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
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+    "region_group": "Europe",
+    "notes": "The chart shows this concurrently with Christian Iberian kingdoms; 1238 is the visible boundary with Late Reconquista.",
+    "confidence": "High"
+  },
+  {
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+    "notes": null,
+    "confidence": "High"
+  },
+  {
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
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+    "box_name": "Kingdom of Portugal",
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+    "notes": null,
+    "confidence": "High"
+  },
+  {
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+    "box_name": "Iberian Union",
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "PT_RESTORED",
+    "box_name": "Restored Kingdom of Portugal",
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+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "PT_CONST_MON",
+    "box_name": "Constitutional Monarchy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "PT_FIRST_REP",
+    "box_name": "First Portuguese Republic",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "PT_ESTADO_NOVO",
+    "box_name": "Estado Novo",
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+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
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+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
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+  },
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+    "confidence": "High"
+  },
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+    "notes": null,
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+  },
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+    "box_name": "Kingdom of Asturias",
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+  },
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+    "confidence": "High"
+  },
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+  },
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+    "box_name": "Unification of Spain",
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+  },
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+  {
+    "box_id": "FR_UNNAMED_1792",
+    "box_name": "[Unlabeled France segment]",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1792,
+    "end_year": 1804,
+    "start_label": "1792",
+    "end_label": "1804",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "France",
+    "span_count": 1,
+    "span_start": "France",
+    "span_end": "France",
+    "region_group": "Europe",
+    "notes": "Very thin teal segment; the supplied image shows the 1792 date and milestone #14 but no legible box name.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "NAPOLEON",
+    "box_name": "First French Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1804,
+    "end_year": 1815,
+    "start_label": "1804",
+    "end_label": "1815",
+    "color_name": "black",
+    "color_hex": "#151515",
+    "span": "Portugal; Spain; France; Italy; Germany",
+    "span_count": 5,
+    "span_start": "Portugal",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": "Irregular/step-shaped occupation band; edge labels vary by modern-country column (e.g. 1807 Portugal, 1808 Spain, 1805 Italy, 1806 Germany).",
+    "confidence": "High"
+  },
+  {
+    "box_id": "FR_REPUBLICAN",
+    "box_name": "Republican France",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1815,
+    "end_year": 1946,
+    "start_label": "1815",
+    "end_label": "1946",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "France",
+    "span_count": 1,
+    "span_start": "France",
+    "span_end": "France",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "FR_MODERN",
+    "box_name": "France",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1946,
+    "end_year": 2026,
+    "start_label": "1946",
+    "end_label": "Present",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "France",
+    "span_count": 1,
+    "span_start": "France",
+    "span_end": "France",
+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_ITALIC",
+    "box_name": "Italic Tribes",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1200,
+    "end_year": -753,
+    "start_label": "c. 1200 BCE",
+    "end_label": "753 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_ROMAN_KINGDOM",
+    "box_name": "Roman Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -753,
+    "end_year": -509,
+    "start_label": "753 BCE",
+    "end_label": "509 BCE",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_OSTROGOTH",
+    "box_name": "Ostrogothic Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 493,
+    "end_year": 553,
+    "start_label": "493",
+    "end_label": "553",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_BYZANTINE",
+    "box_name": "Byzantine Italy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 553,
+    "end_year": 774,
+    "start_label": "553",
+    "end_label": "774",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_LOMBARD",
+    "box_name": "Lombard Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 568,
+    "end_year": 774,
+    "start_label": "568",
+    "end_label": "774",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_MEDIEVAL_STATES",
+    "box_name": "Medieval Italian States",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 774,
+    "end_year": 1494,
+    "start_label": "774",
+    "end_label": "1494",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_SICILY",
+    "box_name": "Kingdom of Sicily",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1130,
+    "end_year": 1816,
+    "start_label": "1130",
+    "end_label": "1816",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": "Shown concurrently with the Medieval Italian States / Age of Divided Italy in the same modern-country column.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_DIVIDED",
+    "box_name": "Age of Divided Italy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1494,
+    "end_year": 1805,
+    "start_label": "1494",
+    "end_label": "1805",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_BOURBON_SICILY",
+    "box_name": "Bourbon Sicily",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1816,
+    "end_year": 1861,
+    "start_label": "1816",
+    "end_label": "1861",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_KINGDOM",
+    "box_name": "Kingdom of Italy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1861,
+    "end_year": 1946,
+    "start_label": "1861",
+    "end_label": "1946",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IT_MODERN",
+    "box_name": "Italy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1946,
+    "end_year": 2026,
+    "start_label": "1946",
+    "end_label": "Present",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Italy",
+    "span_count": 1,
+    "span_start": "Italy",
+    "span_end": "Italy",
+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_TRIBES",
+    "box_name": "Celtic & Germanic Tribes",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -800,
+    "end_year": 406,
+    "start_label": "c. 800 BCE",
+    "end_label": "406",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_GERMANIC",
+    "box_name": "Germanic Tribes",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 406,
+    "end_year": 481,
+    "start_label": "406",
+    "end_label": "481",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_MIGRATION",
+    "box_name": "Migration Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 481,
+    "end_year": 843,
+    "start_label": "481",
+    "end_label": "843",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Germany; Austria",
+    "span_count": 2,
+    "span_start": "Germany",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EAST_FRANCIA",
+    "box_name": "East Francia",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 843,
+    "end_year": 962,
+    "start_label": "843",
+    "end_label": "962",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Germany; Austria",
+    "span_count": 2,
+    "span_start": "Germany",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_HRE",
+    "box_name": "Holy Roman Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 962,
+    "end_year": 1806,
+    "start_label": "962",
+    "end_label": "1806",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_PRUSSIA",
+    "box_name": "Kingdom of Prussia",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1701,
+    "end_year": 1871,
+    "start_label": "1701",
+    "end_label": "1871",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": "Shown concurrently with the Holy Roman Empire until 1806 and the German Confederation after 1815.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_CONFED",
+    "box_name": "German Confederation",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1815,
+    "end_year": 1871,
+    "start_label": "1815",
+    "end_label": "1871",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_EMPIRE",
+    "box_name": "German Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1871,
+    "end_year": 1919,
+    "start_label": "1871",
+    "end_label": "1919",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_WEIMAR",
+    "box_name": "Weimar Republic",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1919,
+    "end_year": 1933,
+    "start_label": "1919",
+    "end_label": "1933",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_NAZI",
+    "box_name": "Nazi Germany",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1933,
+    "end_year": 1945,
+    "start_label": "1933",
+    "end_label": "1945",
+    "color_name": "black",
+    "color_hex": "#151515",
+    "span": "Germany; Austria",
+    "span_count": 2,
+    "span_start": "Germany",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": "The black segment extends into the Austrian alignment for the Anschluss period.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_EW",
+    "box_name": "East and West Germany",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1945,
+    "end_year": 1990,
+    "start_label": "1945",
+    "end_label": "1990",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "DE_MODERN",
+    "box_name": "Germany",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1990,
+    "end_year": 2026,
+    "start_label": "1990",
+    "end_label": "Present",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Germany",
+    "span_count": 1,
+    "span_start": "Germany",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_HALLSTATT",
+    "box_name": "Hallstatt Culture",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -800,
+    "end_year": -400,
+    "start_label": "c. 800 BCE",
+    "end_label": "c. 400 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_NORICUM",
+    "box_name": "Celtic Kingdom of Noricum",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -400,
+    "end_year": -16,
+    "start_label": "c. 400 BCE",
+    "end_label": "16 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_POSTROMAN",
+    "box_name": "Post-Roman Germanic Kingdoms",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 476,
+    "end_year": 568,
+    "start_label": "476",
+    "end_label": "568",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_BAVARIA",
+    "box_name": "Duchy of Bavaria",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 568,
+    "end_year": 788,
+    "start_label": "568",
+    "end_label": "788",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_MARGRAVIATE",
+    "box_name": "Margraviate of Austria",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 976,
+    "end_year": 1156,
+    "start_label": "976",
+    "end_label": "1156",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_DUCHY",
+    "box_name": "Duchy of Austria",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1156,
+    "end_year": 1453,
+    "start_label": "1156",
+    "end_label": "1453",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_HABSBURG",
+    "box_name": "Habsburg Austria",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1453,
+    "end_year": 1804,
+    "start_label": "1453",
+    "end_label": "1804",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_EMPIRE",
+    "box_name": "Austrian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1804,
+    "end_year": 1867,
+    "start_label": "1804",
+    "end_label": "1867",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_AH",
+    "box_name": "Austria-Hungary",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1867,
+    "end_year": 1918,
+    "start_label": "1867",
+    "end_label": "1918",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "AT_FIRST_REP",
+    "box_name": "First Austrian Republic",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1918,
+    "end_year": 1938,
+    "start_label": "1918",
+    "end_label": "1938",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": "The 1938 end is inferred from the adjacent Nazi Germany/Anschluss band; the supplied crop shows 1918 clearly.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "AT_SECOND_REP",
+    "box_name": "Second Austrian Republic",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1945,
+    "end_year": 1955,
+    "start_label": "1945",
+    "end_label": "1955",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": "Thin labeled segment between the wartime gap and the modern Austria box.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "AT_MODERN",
+    "box_name": "Austria",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1955,
+    "end_year": 2026,
+    "start_label": "1955",
+    "end_label": "Present",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Austria",
+    "span_count": 1,
+    "span_start": "Austria",
+    "span_end": "Austria",
+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_AEGEAN",
+    "box_name": "Aegean Civilizations",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -3000,
+    "end_year": -1600,
+    "start_label": "c. 3000 BCE",
+    "end_label": "c. 1600 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_MYCENAEAN",
+    "box_name": "Mycenaean Civilization",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1600,
+    "end_year": -1100,
+    "start_label": "c. 1600 BCE",
+    "end_label": "c. 1100 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_DARK",
+    "box_name": "Greek Dark Age",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1100,
+    "end_year": -800,
+    "start_label": "c. 1100 BCE",
+    "end_label": "c. 800 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_CLASSICAL",
+    "box_name": "Classical Greek City-States",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -800,
+    "end_year": -338,
+    "start_label": "c. 800 BCE",
+    "end_label": "338 BCE",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_HELLENISTIC",
+    "box_name": "Hellenistic Age",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -323,
+    "end_year": -146,
+    "start_label": "323 BCE",
+    "end_label": "146 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_SUCCESSOR",
+    "box_name": "Greek Successor States",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1204,
+    "end_year": 1453,
+    "start_label": "1204",
+    "end_label": "1453",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_KINGDOM1",
+    "box_name": "Kingdom of Greece",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1832,
+    "end_year": 1924,
+    "start_label": "1832",
+    "end_label": "1924",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_REPUBLIC",
+    "box_name": "Greek Republic",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1924,
+    "end_year": 1935,
+    "start_label": "1924",
+    "end_label": "1935",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_KINGDOM2",
+    "box_name": "Kingdom of Greece",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1935,
+    "end_year": 1973,
+    "start_label": "1935",
+    "end_label": "1973",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "GR_MODERN",
+    "box_name": "Greece",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1973,
+    "end_year": 2026,
+    "start_label": "1973",
+    "end_label": "Present",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Greece",
+    "span_count": 1,
+    "span_start": "Greece",
+    "span_end": "Greece",
+    "region_group": "Europe",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_HITTITE",
+    "box_name": "Hittite Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1700,
+    "end_year": -1200,
+    "start_label": "c. 1700 BCE",
+    "end_label": "c. 1200 BCE",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_NEOHITTITE",
+    "box_name": "Neo-Hittite Kingdoms",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1200,
+    "end_year": -700,
+    "start_label": "c. 1200 BCE",
+    "end_label": "c. 700 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_LYDIA",
+    "box_name": "Kingdom of Lydia",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -700,
+    "end_year": -546,
+    "start_label": "c. 700 BCE",
+    "end_label": "546 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_HELLENISTIC",
+    "box_name": "Hellenistic Kingdoms",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -323,
+    "end_year": -133,
+    "start_label": "323 BCE",
+    "end_label": "133 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_LATIN",
+    "box_name": "Latin Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1204,
+    "end_year": 1261,
+    "start_label": "1204",
+    "end_label": "1261",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_RESTORED_BYZ",
+    "box_name": "Restored Byzantine Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1261,
+    "end_year": 1453,
+    "start_label": "1261",
+    "end_label": "1453",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_RUM",
+    "box_name": "Sultanate of Rum",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1077,
+    "end_year": 1308,
+    "start_label": "1077",
+    "end_label": "1308",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "TR_MODERN",
+    "box_name": "Turkey",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1923,
+    "end_year": 2026,
+    "start_label": "1923",
+    "end_label": "Present",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Turkey",
+    "span_count": 1,
+    "span_start": "Turkey",
+    "span_end": "Turkey",
+    "region_group": "Europe/Asia",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "ROMAN_REPUBLIC",
+    "box_name": "Roman Republic",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -509,
+    "end_year": -27,
+    "start_label": "509 BCE",
+    "end_label": "27 BCE",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Portugal; Spain; France; Italy; Greece; Turkey",
+    "span_count": 6,
+    "span_start": "Portugal",
+    "span_end": "Turkey",
+    "region_group": "Europe",
+    "notes": "Step-shaped expansion: the chart shows different entry dates by modern-country alignment (e.g. 218 BCE Iberia, 58 BCE Gaul, 146/133 BCE Greece/Anatolia).",
+    "confidence": "High"
+  },
+  {
+    "box_id": "ROMAN_EMPIRE",
+    "box_name": "Roman Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -27,
+    "end_year": 410,
+    "start_label": "27 BCE",
+    "end_label": "395 / 406 / 410",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "United Kingdom; Portugal; Spain; France; Italy; Germany; Austria; Greece; Turkey; Egypt",
+    "span_count": 10,
+    "span_start": "United Kingdom",
+    "span_end": "Egypt",
+    "region_group": "Europe/Mediterranean",
+    "notes": "Large step-shaped box. The core split is labeled 395; peripheral country segments terminate at different dates, including 406 and 410.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "WESTERN_ROMAN",
+    "box_name": "Western Roman Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 395,
+    "end_year": 476,
+    "start_label": "395",
+    "end_label": "476",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Spain; France; Italy; Germany",
+    "span_count": 4,
+    "span_start": "Spain",
+    "span_end": "Germany",
+    "region_group": "Europe",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "BYZANTINE",
+    "box_name": "Byzantine Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 395,
+    "end_year": 1453,
+    "start_label": "395",
+    "end_label": "1453",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Greece; Turkey; Egypt",
+    "span_count": 3,
+    "span_start": "Greece",
+    "span_end": "Egypt",
+    "region_group": "Europe/Middle East",
+    "notes": "Step-shaped survival: Egypt exits to the Arab Caliphate in 641; Greek/Turkish segments continue through the medieval period.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "PERSIAN",
+    "box_name": "Persian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -550,
+    "end_year": -330,
+    "start_label": "550 / 546 / 539 / 525 BCE",
+    "end_label": "330 BCE",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "Turkey; Egypt; Iraq; Iran; Pakistan; India",
+    "span_count": 6,
+    "span_start": "Turkey",
+    "span_end": "India",
+    "region_group": "Middle East/South Asia",
+    "notes": "Step-shaped western expansion; chart entry dates vary by country alignment.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "MACEDONIAN",
+    "box_name": "Macedonian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -338,
+    "end_year": -323,
+    "start_label": "338 / 334 / 332 / 331 / 330 BCE",
+    "end_label": "323 BCE",
+    "color_name": "black",
+    "color_hex": "#151515",
+    "span": "Greece; Turkey; Egypt; Iraq; Iran; Pakistan; India",
+    "span_count": 7,
+    "span_start": "Greece",
+    "span_end": "India",
+    "region_group": "Europe/Middle East/South Asia",
+    "notes": "Thin black conquest band; dates vary along the horizontal extent.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "OTTOMAN",
+    "box_name": "Ottoman Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1308,
+    "end_year": 1923,
+    "start_label": "1308",
+    "end_label": "1832 / 1923",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Greece; Turkey; Egypt; Iraq",
+    "span_count": 4,
+    "span_start": "Greece",
+    "span_end": "Iraq",
+    "region_group": "Europe/Middle East",
+    "notes": "Large step-shaped box: Turkey segment begins around 1308 and ends 1923; Greece exits 1832; Egypt is shown to 1805; Iraq to 1921.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_EARLY_DYN",
+    "box_name": "Early Dynastic Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -3100,
+    "end_year": -2686,
+    "start_label": "c. 3100 BCE",
+    "end_label": "2686 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_OLD",
+    "box_name": "Old Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2686,
+    "end_year": -2181,
+    "start_label": "2686 BCE",
+    "end_label": "2181 BCE",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_FIRST_INT",
+    "box_name": "First Intermediate Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2181,
+    "end_year": -2055,
+    "start_label": "2181 BCE",
+    "end_label": "2055 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_MIDDLE",
+    "box_name": "Middle Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2055,
+    "end_year": -1650,
+    "start_label": "2055 BCE",
+    "end_label": "1650 BCE",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_SECOND_INT",
+    "box_name": "Second Intermediate Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1650,
+    "end_year": -1550,
+    "start_label": "1650 BCE",
+    "end_label": "1550 BCE",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_NEW",
+    "box_name": "New Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1550,
+    "end_year": -1070,
+    "start_label": "1550 BCE",
+    "end_label": "1070 BCE",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_THIRD_INT",
+    "box_name": "Third Intermediate Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1070,
+    "end_year": -664,
+    "start_label": "1070 BCE",
+    "end_label": "664 BCE",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_LATE",
+    "box_name": "Late Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -664,
+    "end_year": -525,
+    "start_label": "664 BCE",
+    "end_label": "525 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_PTOLEMAIC",
+    "box_name": "Ptolemaic Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -305,
+    "end_year": -30,
+    "start_label": "305 BCE",
+    "end_label": "30 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_FATIMID",
+    "box_name": "Fatimid Caliphate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 969,
+    "end_year": 1171,
+    "start_label": "969",
+    "end_label": "1171",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_AYYUBID",
+    "box_name": "Ayyubid Sultanate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1171,
+    "end_year": 1250,
+    "start_label": "1171",
+    "end_label": "1250",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_MAMLUK",
+    "box_name": "Mamluk Sultanate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1250,
+    "end_year": 1517,
+    "start_label": "1250",
+    "end_label": "1517",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_MUHAMMAD_ALI",
+    "box_name": "Muhammad Ali Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1805,
+    "end_year": 1882,
+    "start_label": "1805",
+    "end_label": "1882",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_COLONIAL",
+    "box_name": "Colonial Egypt",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1882,
+    "end_year": 1922,
+    "start_label": "1882",
+    "end_label": "1922",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_KINGDOM",
+    "box_name": "Kingdom of Egypt",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1922,
+    "end_year": 1953,
+    "start_label": "1922",
+    "end_label": "1953",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "EG_MODERN",
+    "box_name": "Egypt",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1953,
+    "end_year": 2026,
+    "start_label": "1953",
+    "end_label": "Present",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Egypt",
+    "span_count": 1,
+    "span_start": "Egypt",
+    "span_end": "Egypt",
+    "region_group": "Middle East/North Africa",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_SUMER",
+    "box_name": "Sumerian Civilization",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -4500,
+    "end_year": -2334,
+    "start_label": "c. 4500 BCE",
+    "end_label": "2334 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": "Box begins above the chart's 3000 BCE reference range.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_AKKAD",
+    "box_name": "Akkadian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2334,
+    "end_year": -2154,
+    "start_label": "2334 BCE",
+    "end_label": "2154 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_SUMER_REN",
+    "box_name": "Sumerian Renaissance",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2154,
+    "end_year": -1894,
+    "start_label": "2154 BCE",
+    "end_label": "1894 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_OLD_BAB",
+    "box_name": "Old Babylonian Kingdom",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1894,
+    "end_year": -1595,
+    "start_label": "1894 BCE",
+    "end_label": "1595 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_KASSITE",
+    "box_name": "Kassite Babylon",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1595,
+    "end_year": -1365,
+    "start_label": "1595 BCE",
+    "end_label": "1365 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_ASSYRIA",
+    "box_name": "Assyrian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1365,
+    "end_year": -625,
+    "start_label": "1365 BCE",
+    "end_label": "625 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_NEO_BAB",
+    "box_name": "Neo-Babylonian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -625,
+    "end_year": -539,
+    "start_label": "625 BCE",
+    "end_label": "539 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_ABBASID",
+    "box_name": "Abbasid Caliphate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 750,
+    "end_year": 1258,
+    "start_label": "750",
+    "end_label": "1258",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Iraq; Iran",
+    "span_count": 2,
+    "span_start": "Iraq",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": "Centered on Baghdad; the chart visually extends the blue Abbasid box across the Iraq/Iran alignment.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_IR_POST_ABB",
+    "box_name": "Post-Abbasid Regional Dynasties",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1258,
+    "end_year": 1501,
+    "start_label": "1258",
+    "end_label": "1501",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Iraq; Iran",
+    "span_count": 2,
+    "span_start": "Iraq",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_KINGDOM",
+    "box_name": "Kingdom of Iraq",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1921,
+    "end_year": 1958,
+    "start_label": "1921",
+    "end_label": "1958",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IQ_MODERN",
+    "box_name": "Iraq",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1958,
+    "end_year": 2026,
+    "start_label": "1958",
+    "end_label": "Present",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "Iraq",
+    "span_count": 1,
+    "span_start": "Iraq",
+    "span_end": "Iraq",
+    "region_group": "Middle East",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_ELAM",
+    "box_name": "Elamite Civilization",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2700,
+    "end_year": -550,
+    "start_label": "c. 2700 BCE",
+    "end_label": "550 BCE",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_TRIBES",
+    "box_name": "Iranian Tribes",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1500,
+    "end_year": -678,
+    "start_label": "c. 1500 BCE",
+    "end_label": "678 BCE",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_MEDIAN",
+    "box_name": "Median Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -678,
+    "end_year": -550,
+    "start_label": "678 BCE",
+    "end_label": "550 BCE",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_SELEUCID",
+    "box_name": "Seleucid Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -312,
+    "end_year": -141,
+    "start_label": "312 BCE",
+    "end_label": "141 BCE",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Iraq; Iran",
+    "span_count": 2,
+    "span_start": "Iraq",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": "The Iranian portion transitions to Parthian rule earlier (247 BCE); 141 BCE is the later western boundary shown.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_PARTHIAN",
+    "box_name": "Parthian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -247,
+    "end_year": 224,
+    "start_label": "247 / 141 BCE",
+    "end_label": "224",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Iraq; Iran",
+    "span_count": 2,
+    "span_start": "Iraq",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": "Step-shaped start: the Iranian segment begins 247 BCE; the western/Iraqi segment is labeled 141 BCE.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_SASANIAN",
+    "box_name": "Sasanian Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 224,
+    "end_year": 651,
+    "start_label": "224",
+    "end_label": "651",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Iraq; Iran",
+    "span_count": 2,
+    "span_start": "Iraq",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "ARAB_CALIPHATE",
+    "box_name": "Arab Caliphate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 633,
+    "end_year": 969,
+    "start_label": "633 / 641 / 651",
+    "end_label": "750 / 969",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "Egypt; Iraq; Iran",
+    "span_count": 3,
+    "span_start": "Egypt",
+    "span_end": "Iran",
+    "region_group": "Middle East/North Africa",
+    "notes": "Step-shaped expansion and succession: 633/641/651 entry labels are visible; Abbasid rule begins 750 while the Egyptian red segment persists to the Fatimid transition in 969.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_SAFAVID",
+    "box_name": "Safavid Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1501,
+    "end_year": 1736,
+    "start_label": "1501",
+    "end_label": "1736",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_AFSHARID",
+    "box_name": "Afsharid Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1736,
+    "end_year": 1796,
+    "start_label": "1736",
+    "end_label": "1796",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_QAJAR",
+    "box_name": "Qajar Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1796,
+    "end_year": 1925,
+    "start_label": "1796",
+    "end_label": "1925",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_PAHLAVI",
+    "box_name": "Pahlavi Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1925,
+    "end_year": 1979,
+    "start_label": "1925",
+    "end_label": "1979",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "IR_MODERN",
+    "box_name": "Iran",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1979,
+    "end_year": 2026,
+    "start_label": "1979",
+    "end_label": "Present",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Iran",
+    "span_count": 1,
+    "span_start": "Iran",
+    "span_end": "Iran",
+    "region_group": "Middle East",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_INDUS",
+    "box_name": "Indus Valley Civilization",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -3300,
+    "end_year": -1500,
+    "start_label": "c. 3300 BCE",
+    "end_label": "c. 1500 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_VEDIC",
+    "box_name": "Vedic Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1500,
+    "end_year": -550,
+    "start_label": "c. 1500 BCE",
+    "end_label": "c. 550 BCE",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_MAHAJANAPADAS",
+    "box_name": "Mahajanapadas",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -550,
+    "end_year": -322,
+    "start_label": "c. 550 BCE",
+    "end_label": "322 BCE",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": "Narrow vertical segment immediately before the Maurya Empire.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_MAURYA",
+    "box_name": "Maurya Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -322,
+    "end_year": -185,
+    "start_label": "322 BCE",
+    "end_label": "185 BCE",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_POST_MAURYA",
+    "box_name": "Post-Mauryan Kingdoms",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -185,
+    "end_year": 320,
+    "start_label": "185 BCE",
+    "end_label": "320",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_GUPTA",
+    "box_name": "Gupta Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 320,
+    "end_year": 550,
+    "start_label": "320",
+    "end_label": "550",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_POST_GUPTA",
+    "box_name": "Post-Gupta Kingdoms",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 550,
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+    "start_label": "550",
+    "end_label": "606",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_HARSHA",
+    "box_name": "Harsha's Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 606,
+    "end_year": 647,
+    "start_label": "606",
+    "end_label": "647",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_REGIONAL",
+    "box_name": "Regional Kingdoms",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 647,
+    "end_year": 1206,
+    "start_label": "647",
+    "end_label": "1206",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_DELHI",
+    "box_name": "Delhi Sultanate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1206,
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+    "start_label": "1206",
+    "end_label": "1526",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_MUGHAL",
+    "box_name": "Mughal Empire",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1526,
+    "end_year": 1858,
+    "start_label": "1526",
+    "end_label": "1858",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "SA_COLONIAL_INDIA",
+    "box_name": "Colonial India",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1858,
+    "end_year": 1947,
+    "start_label": "1858",
+    "end_label": "1947",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Pakistan; India",
+    "span_count": 2,
+    "span_start": "Pakistan",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "PK_MODERN",
+    "box_name": "Pakistan",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1947,
+    "end_year": 2026,
+    "start_label": "1947",
+    "end_label": "Present",
+    "color_name": "blue",
+    "color_hex": "#4FB0EC",
+    "span": "Pakistan",
+    "span_count": 1,
+    "span_start": "Pakistan",
+    "span_end": "Pakistan",
+    "region_group": "South Asia",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "IN_MODERN",
+    "box_name": "India",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1947,
+    "end_year": 2026,
+    "start_label": "1947",
+    "end_label": "Present",
+    "color_name": "light_blue",
+    "color_hex": "#8FBFEA",
+    "span": "India",
+    "span_count": 1,
+    "span_start": "India",
+    "span_end": "India",
+    "region_group": "South Asia",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_LIANGZHU",
+    "box_name": "Liangzhu Culture",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -3000,
+    "end_year": -2070,
+    "start_label": "c. 3000 BCE",
+    "end_label": "c. 2070 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_XIA",
+    "box_name": "Xia Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -2070,
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+    "start_label": "c. 2070 BCE",
+    "end_label": "c. 1600 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_SHANG",
+    "box_name": "Shang Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1600,
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+    "start_label": "c. 1600 BCE",
+    "end_label": "1046 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_ZHOU",
+    "box_name": "Zhou Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -1046,
+    "end_year": -221,
+    "start_label": "1046 BCE",
+    "end_label": "221 BCE",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_QIN",
+    "box_name": "Qin Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -221,
+    "end_year": -202,
+    "start_label": "221 BCE",
+    "end_label": "202 BCE",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_HAN",
+    "box_name": "Han Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -202,
+    "end_year": 220,
+    "start_label": "202 BCE",
+    "end_label": "220",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_DIVISION",
+    "box_name": "Age of Division",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "220",
+    "end_label": "589",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_SUI",
+    "box_name": "Sui Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 589,
+    "end_year": 618,
+    "start_label": "589",
+    "end_label": "618",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_TANG",
+    "box_name": "Tang Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 618,
+    "end_year": 907,
+    "start_label": "618",
+    "end_label": "907",
+    "color_name": "red",
+    "color_hex": "#FF6F75",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_FIVE",
+    "box_name": "Five Dynasties Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 907,
+    "end_year": 960,
+    "start_label": "907",
+    "end_label": "960",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_SONG",
+    "box_name": "Song Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "end_year": 1271,
+    "start_label": "960",
+    "end_label": "1271",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_YUAN",
+    "box_name": "Yuan Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "end_year": 1368,
+    "start_label": "1271",
+    "end_label": "1368",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_MING",
+    "box_name": "Ming Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1368,
+    "end_year": 1644,
+    "start_label": "1368",
+    "end_label": "1644",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_QING",
+    "box_name": "Qing Dynasty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "1644",
+    "end_label": "1912",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_REPUBLIC",
+    "box_name": "Republic of China",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1912,
+    "end_year": 1949,
+    "start_label": "1912",
+    "end_label": "1949",
+    "color_name": "orange",
+    "color_hex": "#FD9E3A",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "CN_MODERN",
+    "box_name": "China",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1949,
+    "end_year": 2026,
+    "start_label": "1949",
+    "end_label": "Present",
+    "color_name": "yellow",
+    "color_hex": "#FFD682",
+    "span": "China",
+    "span_count": 1,
+    "span_start": "China",
+    "span_end": "China",
+    "region_group": "East Asia",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_JOMON",
+    "box_name": "Jōmon Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "c. Prehistory",
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+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": "The chart uses 'c. Prehistory' rather than a numeric start year.",
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_YAYOI",
+    "box_name": "Yayoi Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": -300,
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+    "start_label": "c. 300 BCE",
+    "end_label": "250",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_YAMATO",
+    "box_name": "Yamato State",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 250,
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+    "start_label": "250",
+    "end_label": "710",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_NARA",
+    "box_name": "Nara Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "end_year": 794,
+    "start_label": "710",
+    "end_label": "794",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_HEIAN",
+    "box_name": "Heian Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "794",
+    "end_label": "1185",
+    "color_name": "peach",
+    "color_hex": "#EDC7BF",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_KAMAKURA",
+    "box_name": "Kamakura Shogunate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "1185",
+    "end_label": "1336",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_MUROMACHI",
+    "box_name": "Muromachi Shogunate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
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+    "start_label": "1336",
+    "end_label": "1467",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": "The small following Sengoku strip begins around 1467; the date is hard to read but consistent with the chart placement.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "JP_SENGOKU",
+    "box_name": "Sengoku Period",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1467,
+    "end_year": 1603,
+    "start_label": "c. 1467",
+    "end_label": "1603",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": "Thin strip; start year is partly obscured in the supplied image.",
+    "confidence": "Medium"
+  },
+  {
+    "box_id": "JP_TOKUGAWA",
+    "box_name": "Tokugawa Shogunate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1603,
+    "end_year": 1868,
+    "start_label": "1603",
+    "end_label": "1868",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_MEIJI",
+    "box_name": "Meiji Era",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1868,
+    "end_year": 1912,
+    "start_label": "1868",
+    "end_label": "1912",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_EMPIRE",
+    "box_name": "Empire of Japan",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1912,
+    "end_year": 1947,
+    "start_label": "1912",
+    "end_label": "1947",
+    "color_name": "teal",
+    "color_hex": "#89DCCB",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "box_id": "JP_MODERN",
+    "box_name": "Japan",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "start_year": 1947,
+    "end_year": 2026,
+    "start_label": "1947",
+    "end_label": "Present",
+    "color_name": "green",
+    "color_hex": "#60B787",
+    "span": "Japan",
+    "span_count": 1,
+    "span_start": "Japan",
+    "span_end": "Japan",
+    "region_group": "East Asia",
+    "notes": "Present encoded as 2026 for plotting.",
+    "confidence": "High"
+  }
+]
diff --git a/projects/world-history/data/links.json b/projects/world-history/data/links.json
new file mode 100644
index 0000000..42fa535
--- /dev/null
+++ b/projects/world-history/data/links.json
@@ -0,0 +1,79 @@
+[
+  {
+    "link_id": "LINK-001",
+    "source_box_id": "ROMAN_EMPIRE",
+    "target_box_id": "WESTERN_ROMAN",
+    "year": 395,
+    "relation_type": "partition",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Division_of_the_Roman_Empire",
+    "notes": "Death of Theodosius I; the empire was permanently divided between his sons, Honorius (West) and Arcadius (East)."
+  },
+  {
+    "link_id": "LINK-002",
+    "source_box_id": "ROMAN_EMPIRE",
+    "target_box_id": "BYZANTINE",
+    "year": 395,
+    "relation_type": "partition",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Division_of_the_Roman_Empire",
+    "notes": "Same 395 division; the Eastern half is represented in this dataset by the Byzantine Empire box, whose start_year (395) matches."
+  },
+  {
+    "link_id": "LINK-003",
+    "source_box_id": "FR_FRANKISH",
+    "target_box_id": "FR_WEST_FRANCIA",
+    "year": 843,
+    "relation_type": "partition",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Treaty_of_Verdun",
+    "notes": "Treaty of Verdun partitioned the Carolingian Frankish realm among Louis the Pious's three surviving sons."
+  },
+  {
+    "link_id": "LINK-004",
+    "source_box_id": "FR_FRANKISH",
+    "target_box_id": "EAST_FRANCIA",
+    "year": 843,
+    "relation_type": "partition",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Treaty_of_Verdun",
+    "notes": "Same 843 partition; Louis the German's share became East Francia."
+  },
+  {
+    "link_id": "LINK-005",
+    "source_box_id": "FR_WEST_FRANCIA",
+    "target_box_id": "FR_KINGDOM",
+    "year": 987,
+    "relation_type": "dynastic_transition",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Hugh_Capet",
+    "notes": "Election of Hugh Capet ends Carolingian rule in West Francia and begins Capetian-led France; same polity, new dynasty, not a conquest or partition."
+  },
+  {
+    "link_id": "LINK-006",
+    "source_box_id": "EAST_FRANCIA",
+    "target_box_id": "DE_HRE",
+    "year": 962,
+    "relation_type": "institutional_successor",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Holy_Roman_Empire",
+    "notes": "Otto I crowned Holy Roman Emperor; East Francia's kingship becomes the institutional core of the Holy Roman Empire."
+  },
+  {
+    "link_id": "LINK-007",
+    "source_box_id": "BYZANTINE",
+    "target_box_id": "OTTOMAN",
+    "year": 1453,
+    "relation_type": "conquest",
+    "weight_basis": "equal",
+    "confidence": "High",
+    "source_url": "https://en.wikipedia.org/wiki/Fall_of_Constantinople",
+    "notes": "Ottoman conquest of Constantinople ends the Byzantine Empire. The Ottoman Empire box already starts in 1308 in this dataset (per the source poster); this link marks the decisive succession event in the Mediterranean/European sphere, not the Ottoman state's founding."
+  }
+]
diff --git a/projects/world-history/data/population.json b/projects/world-history/data/population.json
new file mode 100644
index 0000000..31a0d38
--- /dev/null
+++ b/projects/world-history/data/population.json
@@ -0,0 +1,7802 @@
+[
+  {
+    "population_id": "US_INDIG:1607:end",
+    "box_id": "US_INDIG",
+    "box_name": "Indigenous Era",
+    "segment_id": null,
+    "year": 1607,
+    "year_label": "1607",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "US_COLONIAL:1607:start",
+    "box_id": "US_COLONIAL",
+    "box_name": "Colonial America",
+    "segment_id": null,
+    "year": 1607,
+    "year_label": "1607",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "US_COLONIAL:1776:end",
+    "box_id": "US_COLONIAL",
+    "box_name": "Colonial America",
+    "segment_id": null,
+    "year": 1776,
+    "year_label": "1776",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "US_MODERN:1776:start",
+    "box_id": "US_MODERN",
+    "box_name": "United States",
+    "segment_id": null,
+    "year": 1776,
+    "year_label": "1776",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "US_MODERN:2026:end",
+    "box_id": "US_MODERN",
+    "box_name": "United States",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CA_INDIG:1608:end",
+    "box_id": "CA_INDIG",
+    "box_name": "Indigenous Era",
+    "segment_id": null,
+    "year": 1608,
+    "year_label": "1608",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CA_COLONIAL:1608:start",
+    "box_id": "CA_COLONIAL",
+    "box_name": "Colonial Canada",
+    "segment_id": null,
+    "year": 1608,
+    "year_label": "1608",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CA_COLONIAL:1867:end",
+    "box_id": "CA_COLONIAL",
+    "box_name": "Colonial Canada",
+    "segment_id": null,
+    "year": 1867,
+    "year_label": "1867",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CA_MODERN:1867:start",
+    "box_id": "CA_MODERN",
+    "box_name": "Canada",
+    "segment_id": null,
+    "year": 1867,
+    "year_label": "1867",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CA_MODERN:2026:end",
+    "box_id": "CA_MODERN",
+    "box_name": "Canada",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "MX_INDIG:-2000:start",
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "segment_id": null,
+    "year": -2000,
+    "year_label": "c. 2000 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "MX_INDIG:1521:end",
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "segment_id": null,
+    "year": 1521,
+    "year_label": "1521",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "LATAM_COLONIAL:1500:start",
+    "box_id": "LATAM_COLONIAL",
+    "box_name": "Colonial Era",
+    "segment_id": null,
+    "year": 1500,
+    "year_label": "1500 / 1521",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "LATAM_COLONIAL:1821:end",
+    "box_id": "LATAM_COLONIAL",
+    "box_name": "Colonial Era",
+    "segment_id": null,
+    "year": 1821,
+    "year_label": "1816 / 1821",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "MX_MODERN:1821:start",
+    "box_id": "MX_MODERN",
+    "box_name": "Mexico",
+    "segment_id": null,
+    "year": 1821,
+    "year_label": "1821",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "MX_MODERN:2026:end",
+    "box_id": "MX_MODERN",
+    "box_name": "Mexico",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AR_INDIG:1500:end",
+    "box_id": "AR_INDIG",
+    "box_name": "Indigenous Era",
+    "segment_id": null,
+    "year": 1500,
+    "year_label": "1500",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AR_MODERN:1816:start",
+    "box_id": "AR_MODERN",
+    "box_name": "Argentina",
+    "segment_id": null,
+    "year": 1816,
+    "year_label": "1816",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AR_MODERN:2026:end",
+    "box_id": "AR_MODERN",
+    "box_name": "Argentina",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AU_INDIG:1788:end",
+    "box_id": "AU_INDIG",
+    "box_name": "Indigenous Era",
+    "segment_id": null,
+    "year": 1788,
+    "year_label": "1788",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AU_COLONIAL:1788:start",
+    "box_id": "AU_COLONIAL",
+    "box_name": "Colonial Australia",
+    "segment_id": null,
+    "year": 1788,
+    "year_label": "1788",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AU_COLONIAL:1901:end",
+    "box_id": "AU_COLONIAL",
+    "box_name": "Colonial Australia",
+    "segment_id": null,
+    "year": 1901,
+    "year_label": "1901",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AU_MODERN:1901:start",
+    "box_id": "AU_MODERN",
+    "box_name": "Australia",
+    "segment_id": null,
+    "year": 1901,
+    "year_label": "1901",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AU_MODERN:2026:end",
+    "box_id": "AU_MODERN",
+    "box_name": "Australia",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_CELTIC:43:end",
+    "box_id": "UK_CELTIC",
+    "box_name": "Celtic Era",
+    "segment_id": null,
+    "year": 43,
+    "year_label": "43",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_SUBROMAN:410:start",
+    "box_id": "UK_SUBROMAN",
+    "box_name": "Sub-Roman Britain",
+    "segment_id": null,
+    "year": 410,
+    "year_label": "410",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_SUBROMAN:500:end",
+    "box_id": "UK_SUBROMAN",
+    "box_name": "Sub-Roman Britain",
+    "segment_id": null,
+    "year": 500,
+    "year_label": "500",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_ANGLOSAXON:500:start",
+    "box_id": "UK_ANGLOSAXON",
+    "box_name": "Anglo-Saxon Era",
+    "segment_id": null,
+    "year": 500,
+    "year_label": "500",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_ANGLOSAXON:829:end",
+    "box_id": "UK_ANGLOSAXON",
+    "box_name": "Anglo-Saxon Era",
+    "segment_id": null,
+    "year": 829,
+    "year_label": "829",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_WESSEX:829:start",
+    "box_id": "UK_WESSEX",
+    "box_name": "Wessex Dynasty",
+    "segment_id": null,
+    "year": 829,
+    "year_label": "829",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_WESSEX:1066:end",
+    "box_id": "UK_WESSEX",
+    "box_name": "Wessex Dynasty",
+    "segment_id": null,
+    "year": 1066,
+    "year_label": "1066",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_NORMAN:1066:start",
+    "box_id": "UK_NORMAN",
+    "box_name": "Norman Dynasty",
+    "segment_id": null,
+    "year": 1066,
+    "year_label": "1066",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_NORMAN:1154:end",
+    "box_id": "UK_NORMAN",
+    "box_name": "Norman Dynasty",
+    "segment_id": null,
+    "year": 1154,
+    "year_label": "1154",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_PLANTAGENET:1154:start",
+    "box_id": "UK_PLANTAGENET",
+    "box_name": "Plantagenet Dynasty",
+    "segment_id": null,
+    "year": 1154,
+    "year_label": "1154",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_PLANTAGENET:1485:end",
+    "box_id": "UK_PLANTAGENET",
+    "box_name": "Plantagenet Dynasty",
+    "segment_id": null,
+    "year": 1485,
+    "year_label": "1485",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_TUDOR:1485:start",
+    "box_id": "UK_TUDOR",
+    "box_name": "Tudor Dynasty",
+    "segment_id": null,
+    "year": 1485,
+    "year_label": "1485",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_TUDOR:1603:end",
+    "box_id": "UK_TUDOR",
+    "box_name": "Tudor Dynasty",
+    "segment_id": null,
+    "year": 1603,
+    "year_label": "1603",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_STUART:1603:start",
+    "box_id": "UK_STUART",
+    "box_name": "Stuart Dynasty",
+    "segment_id": null,
+    "year": 1603,
+    "year_label": "1603",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_STUART:1714:end",
+    "box_id": "UK_STUART",
+    "box_name": "Stuart Dynasty",
+    "segment_id": null,
+    "year": 1714,
+    "year_label": "1714",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_HANOVER:1714:start",
+    "box_id": "UK_HANOVER",
+    "box_name": "Hanoverian Dynasty",
+    "segment_id": null,
+    "year": 1714,
+    "year_label": "1714",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_HANOVER:1917:end",
+    "box_id": "UK_HANOVER",
+    "box_name": "Hanoverian Dynasty",
+    "segment_id": null,
+    "year": 1917,
+    "year_label": "1917",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_MODERN:1917:start",
+    "box_id": "UK_MODERN",
+    "box_name": "United Kingdom",
+    "segment_id": null,
+    "year": 1917,
+    "year_label": "1917",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "UK_MODERN:2026:end",
+    "box_id": "UK_MODERN",
+    "box_name": "United Kingdom",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_TRIBES:-600:start",
+    "box_id": "PT_TRIBES",
+    "box_name": "Lusitanians and Other Tribes",
+    "segment_id": null,
+    "year": -600,
+    "year_label": "c. 600 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_TRIBES:-218:end",
+    "box_id": "PT_TRIBES",
+    "box_name": "Lusitanians and Other Tribes",
+    "segment_id": null,
+    "year": -218,
+    "year_label": "218 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IBERIA_VISIGOTH:418:start",
+    "box_id": "IBERIA_VISIGOTH",
+    "box_name": "Visigothic Kingdom",
+    "segment_id": null,
+    "year": 418,
+    "year_label": "418",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IBERIA_VISIGOTH:711:end",
+    "box_id": "IBERIA_VISIGOTH",
+    "box_name": "Visigothic Kingdom",
+    "segment_id": null,
+    "year": 711,
+    "year_label": "711",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_SUEBI:409:start",
+    "box_id": "PT_SUEBI",
+    "box_name": "Suebi Kingdom",
+    "segment_id": null,
+    "year": 409,
+    "year_label": "409",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_SUEBI:585:end",
+    "box_id": "PT_SUEBI",
+    "box_name": "Suebi Kingdom",
+    "segment_id": null,
+    "year": 585,
+    "year_label": "585",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IBERIA_ALANDALUS:711:start",
+    "box_id": "IBERIA_ALANDALUS",
+    "box_name": "Al-Andalus",
+    "segment_id": null,
+    "year": 711,
+    "year_label": "711",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IBERIA_ALANDALUS:1238:end",
+    "box_id": "IBERIA_ALANDALUS",
+    "box_name": "Al-Andalus",
+    "segment_id": null,
+    "year": 1238,
+    "year_label": "1238",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_COUNTY1:868:start",
+    "box_id": "PT_COUNTY1",
+    "box_name": "First County of Portugal",
+    "segment_id": null,
+    "year": 868,
+    "year_label": "868",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_COUNTY1:1095:end",
+    "box_id": "PT_COUNTY1",
+    "box_name": "First County of Portugal",
+    "segment_id": null,
+    "year": 1095,
+    "year_label": "1095",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_COUNTY2:1095:start",
+    "box_id": "PT_COUNTY2",
+    "box_name": "Second County of Portugal",
+    "segment_id": null,
+    "year": 1095,
+    "year_label": "1095",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_COUNTY2:1139:end",
+    "box_id": "PT_COUNTY2",
+    "box_name": "Second County of Portugal",
+    "segment_id": null,
+    "year": 1139,
+    "year_label": "1139",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_KINGDOM:1139:start",
+    "box_id": "PT_KINGDOM",
+    "box_name": "Kingdom of Portugal",
+    "segment_id": null,
+    "year": 1139,
+    "year_label": "1139",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_KINGDOM:1580:end",
+    "box_id": "PT_KINGDOM",
+    "box_name": "Kingdom of Portugal",
+    "segment_id": null,
+    "year": 1580,
+    "year_label": "1580",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_IBERIAN_UNION:1580:start",
+    "box_id": "PT_IBERIAN_UNION",
+    "box_name": "Iberian Union",
+    "segment_id": null,
+    "year": 1580,
+    "year_label": "1580",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_IBERIAN_UNION:1640:end",
+    "box_id": "PT_IBERIAN_UNION",
+    "box_name": "Iberian Union",
+    "segment_id": null,
+    "year": 1640,
+    "year_label": "1640",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_RESTORED:1640:start",
+    "box_id": "PT_RESTORED",
+    "box_name": "Restored Kingdom of Portugal",
+    "segment_id": null,
+    "year": 1640,
+    "year_label": "1640",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_RESTORED:1807:end",
+    "box_id": "PT_RESTORED",
+    "box_name": "Restored Kingdom of Portugal",
+    "segment_id": null,
+    "year": 1807,
+    "year_label": "1807",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_CONST_MON:1807:start",
+    "box_id": "PT_CONST_MON",
+    "box_name": "Constitutional Monarchy",
+    "segment_id": null,
+    "year": 1807,
+    "year_label": "1807",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_CONST_MON:1910:end",
+    "box_id": "PT_CONST_MON",
+    "box_name": "Constitutional Monarchy",
+    "segment_id": null,
+    "year": 1910,
+    "year_label": "1910",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_FIRST_REP:1910:start",
+    "box_id": "PT_FIRST_REP",
+    "box_name": "First Portuguese Republic",
+    "segment_id": null,
+    "year": 1910,
+    "year_label": "1910",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_FIRST_REP:1933:end",
+    "box_id": "PT_FIRST_REP",
+    "box_name": "First Portuguese Republic",
+    "segment_id": null,
+    "year": 1933,
+    "year_label": "1933",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_ESTADO_NOVO:1933:start",
+    "box_id": "PT_ESTADO_NOVO",
+    "box_name": "Estado Novo",
+    "segment_id": null,
+    "year": 1933,
+    "year_label": "1933",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_ESTADO_NOVO:1976:end",
+    "box_id": "PT_ESTADO_NOVO",
+    "box_name": "Estado Novo",
+    "segment_id": null,
+    "year": 1976,
+    "year_label": "1976",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_MODERN:1976:start",
+    "box_id": "PT_MODERN",
+    "box_name": "Portugal",
+    "segment_id": null,
+    "year": 1976,
+    "year_label": "1976",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PT_MODERN:2026:end",
+    "box_id": "PT_MODERN",
+    "box_name": "Portugal",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_IBERIAN:-1200:start",
+    "box_id": "ES_IBERIAN",
+    "box_name": "Iberian & Celtic Tribes",
+    "segment_id": null,
+    "year": -1200,
+    "year_label": "c. 1200 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_IBERIAN:-241:end",
+    "box_id": "ES_IBERIAN",
+    "box_name": "Iberian & Celtic Tribes",
+    "segment_id": null,
+    "year": -241,
+    "year_label": "241 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_CARTHAGE:-241:start",
+    "box_id": "ES_CARTHAGE",
+    "box_name": "Carthaginian Era",
+    "segment_id": null,
+    "year": -241,
+    "year_label": "241 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_CARTHAGE:-218:end",
+    "box_id": "ES_CARTHAGE",
+    "box_name": "Carthaginian Era",
+    "segment_id": null,
+    "year": -218,
+    "year_label": "218 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_ASTURIAS:718:start",
+    "box_id": "ES_ASTURIAS",
+    "box_name": "Kingdom of Asturias",
+    "segment_id": null,
+    "year": 718,
+    "year_label": "718",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_ASTURIAS:910:end",
+    "box_id": "ES_ASTURIAS",
+    "box_name": "Kingdom of Asturias",
+    "segment_id": null,
+    "year": 910,
+    "year_label": "910",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_LEON:910:start",
+    "box_id": "ES_LEON",
+    "box_name": "Kingdom of León",
+    "segment_id": null,
+    "year": 910,
+    "year_label": "910",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_LEON:1238:end",
+    "box_id": "ES_LEON",
+    "box_name": "Kingdom of León",
+    "segment_id": null,
+    "year": 1238,
+    "year_label": "1238",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_LATE_RECON:1238:start",
+    "box_id": "ES_LATE_RECON",
+    "box_name": "Late Reconquista",
+    "segment_id": null,
+    "year": 1238,
+    "year_label": "1238",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_LATE_RECON:1479:end",
+    "box_id": "ES_LATE_RECON",
+    "box_name": "Late Reconquista",
+    "segment_id": null,
+    "year": 1479,
+    "year_label": "1479",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_UNIFICATION:1479:start",
+    "box_id": "ES_UNIFICATION",
+    "box_name": "Unification of Spain",
+    "segment_id": null,
+    "year": 1479,
+    "year_label": "1479",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_UNIFICATION:1516:end",
+    "box_id": "ES_UNIFICATION",
+    "box_name": "Unification of Spain",
+    "segment_id": null,
+    "year": 1516,
+    "year_label": "1516",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_HABSBURG:1516:start",
+    "box_id": "ES_HABSBURG",
+    "box_name": "Habsburg Spain",
+    "segment_id": null,
+    "year": 1516,
+    "year_label": "1516",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_HABSBURG:1700:end",
+    "box_id": "ES_HABSBURG",
+    "box_name": "Habsburg Spain",
+    "segment_id": null,
+    "year": 1700,
+    "year_label": "1700",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_BOURBON_REFORMS:1700:start",
+    "box_id": "ES_BOURBON_REFORMS",
+    "box_name": "Bourbon Reforms",
+    "segment_id": null,
+    "year": 1700,
+    "year_label": "1700",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_BOURBON_REFORMS:1808:end",
+    "box_id": "ES_BOURBON_REFORMS",
+    "box_name": "Bourbon Reforms",
+    "segment_id": null,
+    "year": 1808,
+    "year_label": "1808",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_CONSTITUTIONAL:1808:start",
+    "box_id": "ES_CONSTITUTIONAL",
+    "box_name": "Constitutional Era",
+    "segment_id": null,
+    "year": 1808,
+    "year_label": "1808",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_CONSTITUTIONAL:1939:end",
+    "box_id": "ES_CONSTITUTIONAL",
+    "box_name": "Constitutional Era",
+    "segment_id": null,
+    "year": 1939,
+    "year_label": "1939",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_FRANCO:1939:start",
+    "box_id": "ES_FRANCO",
+    "box_name": "Francoist Spain",
+    "segment_id": null,
+    "year": 1939,
+    "year_label": "1939",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_FRANCO:1978:end",
+    "box_id": "ES_FRANCO",
+    "box_name": "Francoist Spain",
+    "segment_id": null,
+    "year": 1978,
+    "year_label": "1978",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_MODERN:1978:start",
+    "box_id": "ES_MODERN",
+    "box_name": "Spain",
+    "segment_id": null,
+    "year": 1978,
+    "year_label": "1978",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ES_MODERN:2026:end",
+    "box_id": "ES_MODERN",
+    "box_name": "Spain",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_GAUL:-800:start",
+    "box_id": "FR_GAUL",
+    "box_name": "Gaul",
+    "segment_id": null,
+    "year": -800,
+    "year_label": "c. 800 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_GAUL:-58:end",
+    "box_id": "FR_GAUL",
+    "box_name": "Gaul",
+    "segment_id": null,
+    "year": -58,
+    "year_label": "58 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_FRANKISH:481:start",
+    "box_id": "FR_FRANKISH",
+    "box_name": "Frankish Kingdom",
+    "segment_id": null,
+    "year": 481,
+    "year_label": "481",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_FRANKISH:843:end",
+    "box_id": "FR_FRANKISH",
+    "box_name": "Frankish Kingdom",
+    "segment_id": null,
+    "year": 843,
+    "year_label": "843",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_WEST_FRANCIA:843:start",
+    "box_id": "FR_WEST_FRANCIA",
+    "box_name": "West Francia",
+    "segment_id": null,
+    "year": 843,
+    "year_label": "843",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_WEST_FRANCIA:987:end",
+    "box_id": "FR_WEST_FRANCIA",
+    "box_name": "West Francia",
+    "segment_id": null,
+    "year": 987,
+    "year_label": "987",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_KINGDOM:987:start",
+    "box_id": "FR_KINGDOM",
+    "box_name": "Kingdom of France",
+    "segment_id": null,
+    "year": 987,
+    "year_label": "987",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_KINGDOM:1589:end",
+    "box_id": "FR_KINGDOM",
+    "box_name": "Kingdom of France",
+    "segment_id": null,
+    "year": 1589,
+    "year_label": "1589",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_BOURBON:1589:start",
+    "box_id": "FR_BOURBON",
+    "box_name": "Bourbon France",
+    "segment_id": null,
+    "year": 1589,
+    "year_label": "1589",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_BOURBON:1792:end",
+    "box_id": "FR_BOURBON",
+    "box_name": "Bourbon France",
+    "segment_id": null,
+    "year": 1792,
+    "year_label": "1792",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_UNNAMED_1792:1792:start",
+    "box_id": "FR_UNNAMED_1792",
+    "box_name": "[Unlabeled France segment]",
+    "segment_id": null,
+    "year": 1792,
+    "year_label": "1792",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_UNNAMED_1792:1804:end",
+    "box_id": "FR_UNNAMED_1792",
+    "box_name": "[Unlabeled France segment]",
+    "segment_id": null,
+    "year": 1804,
+    "year_label": "1804",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "NAPOLEON:1804:start",
+    "box_id": "NAPOLEON",
+    "box_name": "First French Empire",
+    "segment_id": null,
+    "year": 1804,
+    "year_label": "1804",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "NAPOLEON:1815:end",
+    "box_id": "NAPOLEON",
+    "box_name": "First French Empire",
+    "segment_id": null,
+    "year": 1815,
+    "year_label": "1815",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_REPUBLICAN:1815:start",
+    "box_id": "FR_REPUBLICAN",
+    "box_name": "Republican France",
+    "segment_id": null,
+    "year": 1815,
+    "year_label": "1815",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_REPUBLICAN:1946:end",
+    "box_id": "FR_REPUBLICAN",
+    "box_name": "Republican France",
+    "segment_id": null,
+    "year": 1946,
+    "year_label": "1946",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_MODERN:1946:start",
+    "box_id": "FR_MODERN",
+    "box_name": "France",
+    "segment_id": null,
+    "year": 1946,
+    "year_label": "1946",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "FR_MODERN:2026:end",
+    "box_id": "FR_MODERN",
+    "box_name": "France",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_ITALIC:-1200:start",
+    "box_id": "IT_ITALIC",
+    "box_name": "Italic Tribes",
+    "segment_id": null,
+    "year": -1200,
+    "year_label": "c. 1200 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_ITALIC:-753:end",
+    "box_id": "IT_ITALIC",
+    "box_name": "Italic Tribes",
+    "segment_id": null,
+    "year": -753,
+    "year_label": "753 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_ROMAN_KINGDOM:-753:start",
+    "box_id": "IT_ROMAN_KINGDOM",
+    "box_name": "Roman Kingdom",
+    "segment_id": null,
+    "year": -753,
+    "year_label": "753 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_ROMAN_KINGDOM:-509:end",
+    "box_id": "IT_ROMAN_KINGDOM",
+    "box_name": "Roman Kingdom",
+    "segment_id": null,
+    "year": -509,
+    "year_label": "509 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_OSTROGOTH:493:start",
+    "box_id": "IT_OSTROGOTH",
+    "box_name": "Ostrogothic Kingdom",
+    "segment_id": null,
+    "year": 493,
+    "year_label": "493",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_OSTROGOTH:553:end",
+    "box_id": "IT_OSTROGOTH",
+    "box_name": "Ostrogothic Kingdom",
+    "segment_id": null,
+    "year": 553,
+    "year_label": "553",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_BYZANTINE:553:start",
+    "box_id": "IT_BYZANTINE",
+    "box_name": "Byzantine Italy",
+    "segment_id": null,
+    "year": 553,
+    "year_label": "553",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_BYZANTINE:774:end",
+    "box_id": "IT_BYZANTINE",
+    "box_name": "Byzantine Italy",
+    "segment_id": null,
+    "year": 774,
+    "year_label": "774",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_LOMBARD:568:start",
+    "box_id": "IT_LOMBARD",
+    "box_name": "Lombard Kingdom",
+    "segment_id": null,
+    "year": 568,
+    "year_label": "568",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_LOMBARD:774:end",
+    "box_id": "IT_LOMBARD",
+    "box_name": "Lombard Kingdom",
+    "segment_id": null,
+    "year": 774,
+    "year_label": "774",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_MEDIEVAL_STATES:774:start",
+    "box_id": "IT_MEDIEVAL_STATES",
+    "box_name": "Medieval Italian States",
+    "segment_id": null,
+    "year": 774,
+    "year_label": "774",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_MEDIEVAL_STATES:1494:end",
+    "box_id": "IT_MEDIEVAL_STATES",
+    "box_name": "Medieval Italian States",
+    "segment_id": null,
+    "year": 1494,
+    "year_label": "1494",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_SICILY:1130:start",
+    "box_id": "IT_SICILY",
+    "box_name": "Kingdom of Sicily",
+    "segment_id": null,
+    "year": 1130,
+    "year_label": "1130",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_SICILY:1816:end",
+    "box_id": "IT_SICILY",
+    "box_name": "Kingdom of Sicily",
+    "segment_id": null,
+    "year": 1816,
+    "year_label": "1816",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_DIVIDED:1494:start",
+    "box_id": "IT_DIVIDED",
+    "box_name": "Age of Divided Italy",
+    "segment_id": null,
+    "year": 1494,
+    "year_label": "1494",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_DIVIDED:1805:end",
+    "box_id": "IT_DIVIDED",
+    "box_name": "Age of Divided Italy",
+    "segment_id": null,
+    "year": 1805,
+    "year_label": "1805",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_BOURBON_SICILY:1816:start",
+    "box_id": "IT_BOURBON_SICILY",
+    "box_name": "Bourbon Sicily",
+    "segment_id": null,
+    "year": 1816,
+    "year_label": "1816",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_BOURBON_SICILY:1861:end",
+    "box_id": "IT_BOURBON_SICILY",
+    "box_name": "Bourbon Sicily",
+    "segment_id": null,
+    "year": 1861,
+    "year_label": "1861",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_KINGDOM:1861:start",
+    "box_id": "IT_KINGDOM",
+    "box_name": "Kingdom of Italy",
+    "segment_id": null,
+    "year": 1861,
+    "year_label": "1861",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_KINGDOM:1946:end",
+    "box_id": "IT_KINGDOM",
+    "box_name": "Kingdom of Italy",
+    "segment_id": null,
+    "year": 1946,
+    "year_label": "1946",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_MODERN:1946:start",
+    "box_id": "IT_MODERN",
+    "box_name": "Italy",
+    "segment_id": null,
+    "year": 1946,
+    "year_label": "1946",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IT_MODERN:2026:end",
+    "box_id": "IT_MODERN",
+    "box_name": "Italy",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_TRIBES:-800:start",
+    "box_id": "DE_TRIBES",
+    "box_name": "Celtic & Germanic Tribes",
+    "segment_id": null,
+    "year": -800,
+    "year_label": "c. 800 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_TRIBES:406:end",
+    "box_id": "DE_TRIBES",
+    "box_name": "Celtic & Germanic Tribes",
+    "segment_id": null,
+    "year": 406,
+    "year_label": "406",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_GERMANIC:406:start",
+    "box_id": "DE_GERMANIC",
+    "box_name": "Germanic Tribes",
+    "segment_id": null,
+    "year": 406,
+    "year_label": "406",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_GERMANIC:481:end",
+    "box_id": "DE_GERMANIC",
+    "box_name": "Germanic Tribes",
+    "segment_id": null,
+    "year": 481,
+    "year_label": "481",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_MIGRATION:481:start",
+    "box_id": "DE_MIGRATION",
+    "box_name": "Migration Period",
+    "segment_id": null,
+    "year": 481,
+    "year_label": "481",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_MIGRATION:843:end",
+    "box_id": "DE_MIGRATION",
+    "box_name": "Migration Period",
+    "segment_id": null,
+    "year": 843,
+    "year_label": "843",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EAST_FRANCIA:843:start",
+    "box_id": "EAST_FRANCIA",
+    "box_name": "East Francia",
+    "segment_id": null,
+    "year": 843,
+    "year_label": "843",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EAST_FRANCIA:962:end",
+    "box_id": "EAST_FRANCIA",
+    "box_name": "East Francia",
+    "segment_id": null,
+    "year": 962,
+    "year_label": "962",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_HRE:962:start",
+    "box_id": "DE_HRE",
+    "box_name": "Holy Roman Empire",
+    "segment_id": null,
+    "year": 962,
+    "year_label": "962",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_HRE:1806:end",
+    "box_id": "DE_HRE",
+    "box_name": "Holy Roman Empire",
+    "segment_id": null,
+    "year": 1806,
+    "year_label": "1806",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_PRUSSIA:1701:start",
+    "box_id": "DE_PRUSSIA",
+    "box_name": "Kingdom of Prussia",
+    "segment_id": null,
+    "year": 1701,
+    "year_label": "1701",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_PRUSSIA:1871:end",
+    "box_id": "DE_PRUSSIA",
+    "box_name": "Kingdom of Prussia",
+    "segment_id": null,
+    "year": 1871,
+    "year_label": "1871",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_CONFED:1815:start",
+    "box_id": "DE_CONFED",
+    "box_name": "German Confederation",
+    "segment_id": null,
+    "year": 1815,
+    "year_label": "1815",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_CONFED:1871:end",
+    "box_id": "DE_CONFED",
+    "box_name": "German Confederation",
+    "segment_id": null,
+    "year": 1871,
+    "year_label": "1871",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_EMPIRE:1871:start",
+    "box_id": "DE_EMPIRE",
+    "box_name": "German Empire",
+    "segment_id": null,
+    "year": 1871,
+    "year_label": "1871",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_EMPIRE:1919:end",
+    "box_id": "DE_EMPIRE",
+    "box_name": "German Empire",
+    "segment_id": null,
+    "year": 1919,
+    "year_label": "1919",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_WEIMAR:1919:start",
+    "box_id": "DE_WEIMAR",
+    "box_name": "Weimar Republic",
+    "segment_id": null,
+    "year": 1919,
+    "year_label": "1919",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_WEIMAR:1933:end",
+    "box_id": "DE_WEIMAR",
+    "box_name": "Weimar Republic",
+    "segment_id": null,
+    "year": 1933,
+    "year_label": "1933",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_NAZI:1933:start",
+    "box_id": "DE_NAZI",
+    "box_name": "Nazi Germany",
+    "segment_id": null,
+    "year": 1933,
+    "year_label": "1933",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_NAZI:1945:end",
+    "box_id": "DE_NAZI",
+    "box_name": "Nazi Germany",
+    "segment_id": null,
+    "year": 1945,
+    "year_label": "1945",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_EW:1945:start",
+    "box_id": "DE_EW",
+    "box_name": "East and West Germany",
+    "segment_id": null,
+    "year": 1945,
+    "year_label": "1945",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_EW:1990:end",
+    "box_id": "DE_EW",
+    "box_name": "East and West Germany",
+    "segment_id": null,
+    "year": 1990,
+    "year_label": "1990",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_MODERN:1990:start",
+    "box_id": "DE_MODERN",
+    "box_name": "Germany",
+    "segment_id": null,
+    "year": 1990,
+    "year_label": "1990",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "DE_MODERN:2026:end",
+    "box_id": "DE_MODERN",
+    "box_name": "Germany",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_HALLSTATT:-800:start",
+    "box_id": "AT_HALLSTATT",
+    "box_name": "Hallstatt Culture",
+    "segment_id": null,
+    "year": -800,
+    "year_label": "c. 800 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_HALLSTATT:-400:end",
+    "box_id": "AT_HALLSTATT",
+    "box_name": "Hallstatt Culture",
+    "segment_id": null,
+    "year": -400,
+    "year_label": "c. 400 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_NORICUM:-400:start",
+    "box_id": "AT_NORICUM",
+    "box_name": "Celtic Kingdom of Noricum",
+    "segment_id": null,
+    "year": -400,
+    "year_label": "c. 400 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_NORICUM:-16:end",
+    "box_id": "AT_NORICUM",
+    "box_name": "Celtic Kingdom of Noricum",
+    "segment_id": null,
+    "year": -16,
+    "year_label": "16 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_POSTROMAN:476:start",
+    "box_id": "AT_POSTROMAN",
+    "box_name": "Post-Roman Germanic Kingdoms",
+    "segment_id": null,
+    "year": 476,
+    "year_label": "476",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_POSTROMAN:568:end",
+    "box_id": "AT_POSTROMAN",
+    "box_name": "Post-Roman Germanic Kingdoms",
+    "segment_id": null,
+    "year": 568,
+    "year_label": "568",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_BAVARIA:568:start",
+    "box_id": "AT_BAVARIA",
+    "box_name": "Duchy of Bavaria",
+    "segment_id": null,
+    "year": 568,
+    "year_label": "568",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_BAVARIA:788:end",
+    "box_id": "AT_BAVARIA",
+    "box_name": "Duchy of Bavaria",
+    "segment_id": null,
+    "year": 788,
+    "year_label": "788",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_MARGRAVIATE:976:start",
+    "box_id": "AT_MARGRAVIATE",
+    "box_name": "Margraviate of Austria",
+    "segment_id": null,
+    "year": 976,
+    "year_label": "976",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_MARGRAVIATE:1156:end",
+    "box_id": "AT_MARGRAVIATE",
+    "box_name": "Margraviate of Austria",
+    "segment_id": null,
+    "year": 1156,
+    "year_label": "1156",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_DUCHY:1156:start",
+    "box_id": "AT_DUCHY",
+    "box_name": "Duchy of Austria",
+    "segment_id": null,
+    "year": 1156,
+    "year_label": "1156",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_DUCHY:1453:end",
+    "box_id": "AT_DUCHY",
+    "box_name": "Duchy of Austria",
+    "segment_id": null,
+    "year": 1453,
+    "year_label": "1453",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_HABSBURG:1453:start",
+    "box_id": "AT_HABSBURG",
+    "box_name": "Habsburg Austria",
+    "segment_id": null,
+    "year": 1453,
+    "year_label": "1453",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_HABSBURG:1804:end",
+    "box_id": "AT_HABSBURG",
+    "box_name": "Habsburg Austria",
+    "segment_id": null,
+    "year": 1804,
+    "year_label": "1804",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_EMPIRE:1804:start",
+    "box_id": "AT_EMPIRE",
+    "box_name": "Austrian Empire",
+    "segment_id": null,
+    "year": 1804,
+    "year_label": "1804",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_EMPIRE:1867:end",
+    "box_id": "AT_EMPIRE",
+    "box_name": "Austrian Empire",
+    "segment_id": null,
+    "year": 1867,
+    "year_label": "1867",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_AH:1867:start",
+    "box_id": "AT_AH",
+    "box_name": "Austria-Hungary",
+    "segment_id": null,
+    "year": 1867,
+    "year_label": "1867",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_AH:1918:end",
+    "box_id": "AT_AH",
+    "box_name": "Austria-Hungary",
+    "segment_id": null,
+    "year": 1918,
+    "year_label": "1918",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_FIRST_REP:1918:start",
+    "box_id": "AT_FIRST_REP",
+    "box_name": "First Austrian Republic",
+    "segment_id": null,
+    "year": 1918,
+    "year_label": "1918",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_FIRST_REP:1938:end",
+    "box_id": "AT_FIRST_REP",
+    "box_name": "First Austrian Republic",
+    "segment_id": null,
+    "year": 1938,
+    "year_label": "1938",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_SECOND_REP:1945:start",
+    "box_id": "AT_SECOND_REP",
+    "box_name": "Second Austrian Republic",
+    "segment_id": null,
+    "year": 1945,
+    "year_label": "1945",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_SECOND_REP:1955:end",
+    "box_id": "AT_SECOND_REP",
+    "box_name": "Second Austrian Republic",
+    "segment_id": null,
+    "year": 1955,
+    "year_label": "1955",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_MODERN:1955:start",
+    "box_id": "AT_MODERN",
+    "box_name": "Austria",
+    "segment_id": null,
+    "year": 1955,
+    "year_label": "1955",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "AT_MODERN:2026:end",
+    "box_id": "AT_MODERN",
+    "box_name": "Austria",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_AEGEAN:-3000:start",
+    "box_id": "GR_AEGEAN",
+    "box_name": "Aegean Civilizations",
+    "segment_id": null,
+    "year": -3000,
+    "year_label": "c. 3000 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_AEGEAN:-1600:end",
+    "box_id": "GR_AEGEAN",
+    "box_name": "Aegean Civilizations",
+    "segment_id": null,
+    "year": -1600,
+    "year_label": "c. 1600 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_MYCENAEAN:-1600:start",
+    "box_id": "GR_MYCENAEAN",
+    "box_name": "Mycenaean Civilization",
+    "segment_id": null,
+    "year": -1600,
+    "year_label": "c. 1600 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_MYCENAEAN:-1100:end",
+    "box_id": "GR_MYCENAEAN",
+    "box_name": "Mycenaean Civilization",
+    "segment_id": null,
+    "year": -1100,
+    "year_label": "c. 1100 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_DARK:-1100:start",
+    "box_id": "GR_DARK",
+    "box_name": "Greek Dark Age",
+    "segment_id": null,
+    "year": -1100,
+    "year_label": "c. 1100 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_DARK:-800:end",
+    "box_id": "GR_DARK",
+    "box_name": "Greek Dark Age",
+    "segment_id": null,
+    "year": -800,
+    "year_label": "c. 800 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_CLASSICAL:-800:start",
+    "box_id": "GR_CLASSICAL",
+    "box_name": "Classical Greek City-States",
+    "segment_id": null,
+    "year": -800,
+    "year_label": "c. 800 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_CLASSICAL:-338:end",
+    "box_id": "GR_CLASSICAL",
+    "box_name": "Classical Greek City-States",
+    "segment_id": null,
+    "year": -338,
+    "year_label": "338 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_HELLENISTIC:-323:start",
+    "box_id": "GR_HELLENISTIC",
+    "box_name": "Hellenistic Age",
+    "segment_id": null,
+    "year": -323,
+    "year_label": "323 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_HELLENISTIC:-146:end",
+    "box_id": "GR_HELLENISTIC",
+    "box_name": "Hellenistic Age",
+    "segment_id": null,
+    "year": -146,
+    "year_label": "146 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_SUCCESSOR:1204:start",
+    "box_id": "GR_SUCCESSOR",
+    "box_name": "Greek Successor States",
+    "segment_id": null,
+    "year": 1204,
+    "year_label": "1204",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_SUCCESSOR:1453:end",
+    "box_id": "GR_SUCCESSOR",
+    "box_name": "Greek Successor States",
+    "segment_id": null,
+    "year": 1453,
+    "year_label": "1453",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_KINGDOM1:1832:start",
+    "box_id": "GR_KINGDOM1",
+    "box_name": "Kingdom of Greece",
+    "segment_id": null,
+    "year": 1832,
+    "year_label": "1832",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_KINGDOM1:1924:end",
+    "box_id": "GR_KINGDOM1",
+    "box_name": "Kingdom of Greece",
+    "segment_id": null,
+    "year": 1924,
+    "year_label": "1924",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_REPUBLIC:1924:start",
+    "box_id": "GR_REPUBLIC",
+    "box_name": "Greek Republic",
+    "segment_id": null,
+    "year": 1924,
+    "year_label": "1924",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_REPUBLIC:1935:end",
+    "box_id": "GR_REPUBLIC",
+    "box_name": "Greek Republic",
+    "segment_id": null,
+    "year": 1935,
+    "year_label": "1935",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_KINGDOM2:1935:start",
+    "box_id": "GR_KINGDOM2",
+    "box_name": "Kingdom of Greece",
+    "segment_id": null,
+    "year": 1935,
+    "year_label": "1935",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_KINGDOM2:1973:end",
+    "box_id": "GR_KINGDOM2",
+    "box_name": "Kingdom of Greece",
+    "segment_id": null,
+    "year": 1973,
+    "year_label": "1973",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_MODERN:1973:start",
+    "box_id": "GR_MODERN",
+    "box_name": "Greece",
+    "segment_id": null,
+    "year": 1973,
+    "year_label": "1973",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "GR_MODERN:2026:end",
+    "box_id": "GR_MODERN",
+    "box_name": "Greece",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_HITTITE:-1700:start",
+    "box_id": "TR_HITTITE",
+    "box_name": "Hittite Empire",
+    "segment_id": null,
+    "year": -1700,
+    "year_label": "c. 1700 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_HITTITE:-1200:end",
+    "box_id": "TR_HITTITE",
+    "box_name": "Hittite Empire",
+    "segment_id": null,
+    "year": -1200,
+    "year_label": "c. 1200 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_NEOHITTITE:-1200:start",
+    "box_id": "TR_NEOHITTITE",
+    "box_name": "Neo-Hittite Kingdoms",
+    "segment_id": null,
+    "year": -1200,
+    "year_label": "c. 1200 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_NEOHITTITE:-700:end",
+    "box_id": "TR_NEOHITTITE",
+    "box_name": "Neo-Hittite Kingdoms",
+    "segment_id": null,
+    "year": -700,
+    "year_label": "c. 700 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_LYDIA:-700:start",
+    "box_id": "TR_LYDIA",
+    "box_name": "Kingdom of Lydia",
+    "segment_id": null,
+    "year": -700,
+    "year_label": "c. 700 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_LYDIA:-546:end",
+    "box_id": "TR_LYDIA",
+    "box_name": "Kingdom of Lydia",
+    "segment_id": null,
+    "year": -546,
+    "year_label": "546 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_HELLENISTIC:-323:start",
+    "box_id": "TR_HELLENISTIC",
+    "box_name": "Hellenistic Kingdoms",
+    "segment_id": null,
+    "year": -323,
+    "year_label": "323 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_HELLENISTIC:-133:end",
+    "box_id": "TR_HELLENISTIC",
+    "box_name": "Hellenistic Kingdoms",
+    "segment_id": null,
+    "year": -133,
+    "year_label": "133 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_LATIN:1204:start",
+    "box_id": "TR_LATIN",
+    "box_name": "Latin Empire",
+    "segment_id": null,
+    "year": 1204,
+    "year_label": "1204",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_LATIN:1261:end",
+    "box_id": "TR_LATIN",
+    "box_name": "Latin Empire",
+    "segment_id": null,
+    "year": 1261,
+    "year_label": "1261",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_RESTORED_BYZ:1261:start",
+    "box_id": "TR_RESTORED_BYZ",
+    "box_name": "Restored Byzantine Empire",
+    "segment_id": null,
+    "year": 1261,
+    "year_label": "1261",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_RESTORED_BYZ:1453:end",
+    "box_id": "TR_RESTORED_BYZ",
+    "box_name": "Restored Byzantine Empire",
+    "segment_id": null,
+    "year": 1453,
+    "year_label": "1453",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_RUM:1077:start",
+    "box_id": "TR_RUM",
+    "box_name": "Sultanate of Rum",
+    "segment_id": null,
+    "year": 1077,
+    "year_label": "1077",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_RUM:1308:end",
+    "box_id": "TR_RUM",
+    "box_name": "Sultanate of Rum",
+    "segment_id": null,
+    "year": 1308,
+    "year_label": "1308",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_MODERN:1923:start",
+    "box_id": "TR_MODERN",
+    "box_name": "Turkey",
+    "segment_id": null,
+    "year": 1923,
+    "year_label": "1923",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "TR_MODERN:2026:end",
+    "box_id": "TR_MODERN",
+    "box_name": "Turkey",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ROMAN_REPUBLIC:-509:start",
+    "box_id": "ROMAN_REPUBLIC",
+    "box_name": "Roman Republic",
+    "segment_id": null,
+    "year": -509,
+    "year_label": "509 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ROMAN_REPUBLIC:-27:end",
+    "box_id": "ROMAN_REPUBLIC",
+    "box_name": "Roman Republic",
+    "segment_id": null,
+    "year": -27,
+    "year_label": "27 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ROMAN_EMPIRE:-27:start",
+    "box_id": "ROMAN_EMPIRE",
+    "box_name": "Roman Empire",
+    "segment_id": null,
+    "year": -27,
+    "year_label": "27 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ROMAN_EMPIRE:410:end",
+    "box_id": "ROMAN_EMPIRE",
+    "box_name": "Roman Empire",
+    "segment_id": null,
+    "year": 410,
+    "year_label": "395 / 406 / 410",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "WESTERN_ROMAN:395:start",
+    "box_id": "WESTERN_ROMAN",
+    "box_name": "Western Roman Empire",
+    "segment_id": null,
+    "year": 395,
+    "year_label": "395",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "WESTERN_ROMAN:476:end",
+    "box_id": "WESTERN_ROMAN",
+    "box_name": "Western Roman Empire",
+    "segment_id": null,
+    "year": 476,
+    "year_label": "476",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "BYZANTINE:395:start",
+    "box_id": "BYZANTINE",
+    "box_name": "Byzantine Empire",
+    "segment_id": null,
+    "year": 395,
+    "year_label": "395",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "BYZANTINE:1453:end",
+    "box_id": "BYZANTINE",
+    "box_name": "Byzantine Empire",
+    "segment_id": null,
+    "year": 1453,
+    "year_label": "1453",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PERSIAN:-550:start",
+    "box_id": "PERSIAN",
+    "box_name": "Persian Empire",
+    "segment_id": null,
+    "year": -550,
+    "year_label": "550 / 546 / 539 / 525 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PERSIAN:-330:end",
+    "box_id": "PERSIAN",
+    "box_name": "Persian Empire",
+    "segment_id": null,
+    "year": -330,
+    "year_label": "330 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "MACEDONIAN:-338:start",
+    "box_id": "MACEDONIAN",
+    "box_name": "Macedonian Empire",
+    "segment_id": null,
+    "year": -338,
+    "year_label": "338 / 334 / 332 / 331 / 330 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "MACEDONIAN:-323:end",
+    "box_id": "MACEDONIAN",
+    "box_name": "Macedonian Empire",
+    "segment_id": null,
+    "year": -323,
+    "year_label": "323 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "OTTOMAN:1308:start",
+    "box_id": "OTTOMAN",
+    "box_name": "Ottoman Empire",
+    "segment_id": null,
+    "year": 1308,
+    "year_label": "1308",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "OTTOMAN:1923:end",
+    "box_id": "OTTOMAN",
+    "box_name": "Ottoman Empire",
+    "segment_id": null,
+    "year": 1923,
+    "year_label": "1832 / 1923",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_EARLY_DYN:-3100:start",
+    "box_id": "EG_EARLY_DYN",
+    "box_name": "Early Dynastic Period",
+    "segment_id": null,
+    "year": -3100,
+    "year_label": "c. 3100 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_EARLY_DYN:-2686:end",
+    "box_id": "EG_EARLY_DYN",
+    "box_name": "Early Dynastic Period",
+    "segment_id": null,
+    "year": -2686,
+    "year_label": "2686 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_OLD:-2686:start",
+    "box_id": "EG_OLD",
+    "box_name": "Old Kingdom",
+    "segment_id": null,
+    "year": -2686,
+    "year_label": "2686 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_OLD:-2181:end",
+    "box_id": "EG_OLD",
+    "box_name": "Old Kingdom",
+    "segment_id": null,
+    "year": -2181,
+    "year_label": "2181 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_FIRST_INT:-2181:start",
+    "box_id": "EG_FIRST_INT",
+    "box_name": "First Intermediate Period",
+    "segment_id": null,
+    "year": -2181,
+    "year_label": "2181 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_FIRST_INT:-2055:end",
+    "box_id": "EG_FIRST_INT",
+    "box_name": "First Intermediate Period",
+    "segment_id": null,
+    "year": -2055,
+    "year_label": "2055 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MIDDLE:-2055:start",
+    "box_id": "EG_MIDDLE",
+    "box_name": "Middle Kingdom",
+    "segment_id": null,
+    "year": -2055,
+    "year_label": "2055 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MIDDLE:-1650:end",
+    "box_id": "EG_MIDDLE",
+    "box_name": "Middle Kingdom",
+    "segment_id": null,
+    "year": -1650,
+    "year_label": "1650 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_SECOND_INT:-1650:start",
+    "box_id": "EG_SECOND_INT",
+    "box_name": "Second Intermediate Period",
+    "segment_id": null,
+    "year": -1650,
+    "year_label": "1650 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_SECOND_INT:-1550:end",
+    "box_id": "EG_SECOND_INT",
+    "box_name": "Second Intermediate Period",
+    "segment_id": null,
+    "year": -1550,
+    "year_label": "1550 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_NEW:-1550:start",
+    "box_id": "EG_NEW",
+    "box_name": "New Kingdom",
+    "segment_id": null,
+    "year": -1550,
+    "year_label": "1550 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_NEW:-1070:end",
+    "box_id": "EG_NEW",
+    "box_name": "New Kingdom",
+    "segment_id": null,
+    "year": -1070,
+    "year_label": "1070 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_THIRD_INT:-1070:start",
+    "box_id": "EG_THIRD_INT",
+    "box_name": "Third Intermediate Period",
+    "segment_id": null,
+    "year": -1070,
+    "year_label": "1070 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_THIRD_INT:-664:end",
+    "box_id": "EG_THIRD_INT",
+    "box_name": "Third Intermediate Period",
+    "segment_id": null,
+    "year": -664,
+    "year_label": "664 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_LATE:-664:start",
+    "box_id": "EG_LATE",
+    "box_name": "Late Period",
+    "segment_id": null,
+    "year": -664,
+    "year_label": "664 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_LATE:-525:end",
+    "box_id": "EG_LATE",
+    "box_name": "Late Period",
+    "segment_id": null,
+    "year": -525,
+    "year_label": "525 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_PTOLEMAIC:-305:start",
+    "box_id": "EG_PTOLEMAIC",
+    "box_name": "Ptolemaic Kingdom",
+    "segment_id": null,
+    "year": -305,
+    "year_label": "305 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_PTOLEMAIC:-30:end",
+    "box_id": "EG_PTOLEMAIC",
+    "box_name": "Ptolemaic Kingdom",
+    "segment_id": null,
+    "year": -30,
+    "year_label": "30 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_FATIMID:969:start",
+    "box_id": "EG_FATIMID",
+    "box_name": "Fatimid Caliphate",
+    "segment_id": null,
+    "year": 969,
+    "year_label": "969",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_FATIMID:1171:end",
+    "box_id": "EG_FATIMID",
+    "box_name": "Fatimid Caliphate",
+    "segment_id": null,
+    "year": 1171,
+    "year_label": "1171",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_AYYUBID:1171:start",
+    "box_id": "EG_AYYUBID",
+    "box_name": "Ayyubid Sultanate",
+    "segment_id": null,
+    "year": 1171,
+    "year_label": "1171",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_AYYUBID:1250:end",
+    "box_id": "EG_AYYUBID",
+    "box_name": "Ayyubid Sultanate",
+    "segment_id": null,
+    "year": 1250,
+    "year_label": "1250",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MAMLUK:1250:start",
+    "box_id": "EG_MAMLUK",
+    "box_name": "Mamluk Sultanate",
+    "segment_id": null,
+    "year": 1250,
+    "year_label": "1250",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MAMLUK:1517:end",
+    "box_id": "EG_MAMLUK",
+    "box_name": "Mamluk Sultanate",
+    "segment_id": null,
+    "year": 1517,
+    "year_label": "1517",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MUHAMMAD_ALI:1805:start",
+    "box_id": "EG_MUHAMMAD_ALI",
+    "box_name": "Muhammad Ali Dynasty",
+    "segment_id": null,
+    "year": 1805,
+    "year_label": "1805",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MUHAMMAD_ALI:1882:end",
+    "box_id": "EG_MUHAMMAD_ALI",
+    "box_name": "Muhammad Ali Dynasty",
+    "segment_id": null,
+    "year": 1882,
+    "year_label": "1882",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_COLONIAL:1882:start",
+    "box_id": "EG_COLONIAL",
+    "box_name": "Colonial Egypt",
+    "segment_id": null,
+    "year": 1882,
+    "year_label": "1882",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_COLONIAL:1922:end",
+    "box_id": "EG_COLONIAL",
+    "box_name": "Colonial Egypt",
+    "segment_id": null,
+    "year": 1922,
+    "year_label": "1922",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_KINGDOM:1922:start",
+    "box_id": "EG_KINGDOM",
+    "box_name": "Kingdom of Egypt",
+    "segment_id": null,
+    "year": 1922,
+    "year_label": "1922",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_KINGDOM:1953:end",
+    "box_id": "EG_KINGDOM",
+    "box_name": "Kingdom of Egypt",
+    "segment_id": null,
+    "year": 1953,
+    "year_label": "1953",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MODERN:1953:start",
+    "box_id": "EG_MODERN",
+    "box_name": "Egypt",
+    "segment_id": null,
+    "year": 1953,
+    "year_label": "1953",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "EG_MODERN:2026:end",
+    "box_id": "EG_MODERN",
+    "box_name": "Egypt",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_SUMER:-4500:start",
+    "box_id": "IQ_SUMER",
+    "box_name": "Sumerian Civilization",
+    "segment_id": null,
+    "year": -4500,
+    "year_label": "c. 4500 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_SUMER:-2334:end",
+    "box_id": "IQ_SUMER",
+    "box_name": "Sumerian Civilization",
+    "segment_id": null,
+    "year": -2334,
+    "year_label": "2334 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_AKKAD:-2334:start",
+    "box_id": "IQ_AKKAD",
+    "box_name": "Akkadian Empire",
+    "segment_id": null,
+    "year": -2334,
+    "year_label": "2334 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_AKKAD:-2154:end",
+    "box_id": "IQ_AKKAD",
+    "box_name": "Akkadian Empire",
+    "segment_id": null,
+    "year": -2154,
+    "year_label": "2154 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_SUMER_REN:-2154:start",
+    "box_id": "IQ_SUMER_REN",
+    "box_name": "Sumerian Renaissance",
+    "segment_id": null,
+    "year": -2154,
+    "year_label": "2154 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_SUMER_REN:-1894:end",
+    "box_id": "IQ_SUMER_REN",
+    "box_name": "Sumerian Renaissance",
+    "segment_id": null,
+    "year": -1894,
+    "year_label": "1894 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_OLD_BAB:-1894:start",
+    "box_id": "IQ_OLD_BAB",
+    "box_name": "Old Babylonian Kingdom",
+    "segment_id": null,
+    "year": -1894,
+    "year_label": "1894 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_OLD_BAB:-1595:end",
+    "box_id": "IQ_OLD_BAB",
+    "box_name": "Old Babylonian Kingdom",
+    "segment_id": null,
+    "year": -1595,
+    "year_label": "1595 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_KASSITE:-1595:start",
+    "box_id": "IQ_KASSITE",
+    "box_name": "Kassite Babylon",
+    "segment_id": null,
+    "year": -1595,
+    "year_label": "1595 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_KASSITE:-1365:end",
+    "box_id": "IQ_KASSITE",
+    "box_name": "Kassite Babylon",
+    "segment_id": null,
+    "year": -1365,
+    "year_label": "1365 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_ASSYRIA:-1365:start",
+    "box_id": "IQ_ASSYRIA",
+    "box_name": "Assyrian Empire",
+    "segment_id": null,
+    "year": -1365,
+    "year_label": "1365 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_ASSYRIA:-625:end",
+    "box_id": "IQ_ASSYRIA",
+    "box_name": "Assyrian Empire",
+    "segment_id": null,
+    "year": -625,
+    "year_label": "625 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_NEO_BAB:-625:start",
+    "box_id": "IQ_NEO_BAB",
+    "box_name": "Neo-Babylonian Empire",
+    "segment_id": null,
+    "year": -625,
+    "year_label": "625 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_NEO_BAB:-539:end",
+    "box_id": "IQ_NEO_BAB",
+    "box_name": "Neo-Babylonian Empire",
+    "segment_id": null,
+    "year": -539,
+    "year_label": "539 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_ABBASID:750:start",
+    "box_id": "IQ_ABBASID",
+    "box_name": "Abbasid Caliphate",
+    "segment_id": null,
+    "year": 750,
+    "year_label": "750",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_ABBASID:1258:end",
+    "box_id": "IQ_ABBASID",
+    "box_name": "Abbasid Caliphate",
+    "segment_id": null,
+    "year": 1258,
+    "year_label": "1258",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_IR_POST_ABB:1258:start",
+    "box_id": "IQ_IR_POST_ABB",
+    "box_name": "Post-Abbasid Regional Dynasties",
+    "segment_id": null,
+    "year": 1258,
+    "year_label": "1258",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_IR_POST_ABB:1501:end",
+    "box_id": "IQ_IR_POST_ABB",
+    "box_name": "Post-Abbasid Regional Dynasties",
+    "segment_id": null,
+    "year": 1501,
+    "year_label": "1501",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_KINGDOM:1921:start",
+    "box_id": "IQ_KINGDOM",
+    "box_name": "Kingdom of Iraq",
+    "segment_id": null,
+    "year": 1921,
+    "year_label": "1921",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_KINGDOM:1958:end",
+    "box_id": "IQ_KINGDOM",
+    "box_name": "Kingdom of Iraq",
+    "segment_id": null,
+    "year": 1958,
+    "year_label": "1958",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_MODERN:1958:start",
+    "box_id": "IQ_MODERN",
+    "box_name": "Iraq",
+    "segment_id": null,
+    "year": 1958,
+    "year_label": "1958",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IQ_MODERN:2026:end",
+    "box_id": "IQ_MODERN",
+    "box_name": "Iraq",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_ELAM:-2700:start",
+    "box_id": "IR_ELAM",
+    "box_name": "Elamite Civilization",
+    "segment_id": null,
+    "year": -2700,
+    "year_label": "c. 2700 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_ELAM:-550:end",
+    "box_id": "IR_ELAM",
+    "box_name": "Elamite Civilization",
+    "segment_id": null,
+    "year": -550,
+    "year_label": "550 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_TRIBES:-1500:start",
+    "box_id": "IR_TRIBES",
+    "box_name": "Iranian Tribes",
+    "segment_id": null,
+    "year": -1500,
+    "year_label": "c. 1500 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_TRIBES:-678:end",
+    "box_id": "IR_TRIBES",
+    "box_name": "Iranian Tribes",
+    "segment_id": null,
+    "year": -678,
+    "year_label": "678 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_MEDIAN:-678:start",
+    "box_id": "IR_MEDIAN",
+    "box_name": "Median Empire",
+    "segment_id": null,
+    "year": -678,
+    "year_label": "678 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_MEDIAN:-550:end",
+    "box_id": "IR_MEDIAN",
+    "box_name": "Median Empire",
+    "segment_id": null,
+    "year": -550,
+    "year_label": "550 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_SELEUCID:-312:start",
+    "box_id": "IR_SELEUCID",
+    "box_name": "Seleucid Empire",
+    "segment_id": null,
+    "year": -312,
+    "year_label": "312 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_SELEUCID:-141:end",
+    "box_id": "IR_SELEUCID",
+    "box_name": "Seleucid Empire",
+    "segment_id": null,
+    "year": -141,
+    "year_label": "141 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_PARTHIAN:-247:start",
+    "box_id": "IR_PARTHIAN",
+    "box_name": "Parthian Empire",
+    "segment_id": null,
+    "year": -247,
+    "year_label": "247 / 141 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_PARTHIAN:224:end",
+    "box_id": "IR_PARTHIAN",
+    "box_name": "Parthian Empire",
+    "segment_id": null,
+    "year": 224,
+    "year_label": "224",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_SASANIAN:224:start",
+    "box_id": "IR_SASANIAN",
+    "box_name": "Sasanian Empire",
+    "segment_id": null,
+    "year": 224,
+    "year_label": "224",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_SASANIAN:651:end",
+    "box_id": "IR_SASANIAN",
+    "box_name": "Sasanian Empire",
+    "segment_id": null,
+    "year": 651,
+    "year_label": "651",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ARAB_CALIPHATE:633:start",
+    "box_id": "ARAB_CALIPHATE",
+    "box_name": "Arab Caliphate",
+    "segment_id": null,
+    "year": 633,
+    "year_label": "633 / 641 / 651",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "ARAB_CALIPHATE:969:end",
+    "box_id": "ARAB_CALIPHATE",
+    "box_name": "Arab Caliphate",
+    "segment_id": null,
+    "year": 969,
+    "year_label": "750 / 969",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_SAFAVID:1501:start",
+    "box_id": "IR_SAFAVID",
+    "box_name": "Safavid Empire",
+    "segment_id": null,
+    "year": 1501,
+    "year_label": "1501",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_SAFAVID:1736:end",
+    "box_id": "IR_SAFAVID",
+    "box_name": "Safavid Empire",
+    "segment_id": null,
+    "year": 1736,
+    "year_label": "1736",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_AFSHARID:1736:start",
+    "box_id": "IR_AFSHARID",
+    "box_name": "Afsharid Empire",
+    "segment_id": null,
+    "year": 1736,
+    "year_label": "1736",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_AFSHARID:1796:end",
+    "box_id": "IR_AFSHARID",
+    "box_name": "Afsharid Empire",
+    "segment_id": null,
+    "year": 1796,
+    "year_label": "1796",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_QAJAR:1796:start",
+    "box_id": "IR_QAJAR",
+    "box_name": "Qajar Dynasty",
+    "segment_id": null,
+    "year": 1796,
+    "year_label": "1796",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_QAJAR:1925:end",
+    "box_id": "IR_QAJAR",
+    "box_name": "Qajar Dynasty",
+    "segment_id": null,
+    "year": 1925,
+    "year_label": "1925",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_PAHLAVI:1925:start",
+    "box_id": "IR_PAHLAVI",
+    "box_name": "Pahlavi Dynasty",
+    "segment_id": null,
+    "year": 1925,
+    "year_label": "1925",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_PAHLAVI:1979:end",
+    "box_id": "IR_PAHLAVI",
+    "box_name": "Pahlavi Dynasty",
+    "segment_id": null,
+    "year": 1979,
+    "year_label": "1979",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_MODERN:1979:start",
+    "box_id": "IR_MODERN",
+    "box_name": "Iran",
+    "segment_id": null,
+    "year": 1979,
+    "year_label": "1979",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IR_MODERN:2026:end",
+    "box_id": "IR_MODERN",
+    "box_name": "Iran",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_INDUS:-3300:start",
+    "box_id": "SA_INDUS",
+    "box_name": "Indus Valley Civilization",
+    "segment_id": null,
+    "year": -3300,
+    "year_label": "c. 3300 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_INDUS:-1500:end",
+    "box_id": "SA_INDUS",
+    "box_name": "Indus Valley Civilization",
+    "segment_id": null,
+    "year": -1500,
+    "year_label": "c. 1500 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_VEDIC:-1500:start",
+    "box_id": "SA_VEDIC",
+    "box_name": "Vedic Period",
+    "segment_id": null,
+    "year": -1500,
+    "year_label": "c. 1500 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_VEDIC:-550:end",
+    "box_id": "SA_VEDIC",
+    "box_name": "Vedic Period",
+    "segment_id": null,
+    "year": -550,
+    "year_label": "c. 550 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_MAHAJANAPADAS:-550:start",
+    "box_id": "SA_MAHAJANAPADAS",
+    "box_name": "Mahajanapadas",
+    "segment_id": null,
+    "year": -550,
+    "year_label": "c. 550 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_MAHAJANAPADAS:-322:end",
+    "box_id": "SA_MAHAJANAPADAS",
+    "box_name": "Mahajanapadas",
+    "segment_id": null,
+    "year": -322,
+    "year_label": "322 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_MAURYA:-322:start",
+    "box_id": "SA_MAURYA",
+    "box_name": "Maurya Empire",
+    "segment_id": null,
+    "year": -322,
+    "year_label": "322 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_MAURYA:-185:end",
+    "box_id": "SA_MAURYA",
+    "box_name": "Maurya Empire",
+    "segment_id": null,
+    "year": -185,
+    "year_label": "185 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_POST_MAURYA:-185:start",
+    "box_id": "SA_POST_MAURYA",
+    "box_name": "Post-Mauryan Kingdoms",
+    "segment_id": null,
+    "year": -185,
+    "year_label": "185 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_POST_MAURYA:320:end",
+    "box_id": "SA_POST_MAURYA",
+    "box_name": "Post-Mauryan Kingdoms",
+    "segment_id": null,
+    "year": 320,
+    "year_label": "320",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_GUPTA:320:start",
+    "box_id": "SA_GUPTA",
+    "box_name": "Gupta Empire",
+    "segment_id": null,
+    "year": 320,
+    "year_label": "320",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_GUPTA:550:end",
+    "box_id": "SA_GUPTA",
+    "box_name": "Gupta Empire",
+    "segment_id": null,
+    "year": 550,
+    "year_label": "550",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_POST_GUPTA:550:start",
+    "box_id": "SA_POST_GUPTA",
+    "box_name": "Post-Gupta Kingdoms",
+    "segment_id": null,
+    "year": 550,
+    "year_label": "550",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_POST_GUPTA:606:end",
+    "box_id": "SA_POST_GUPTA",
+    "box_name": "Post-Gupta Kingdoms",
+    "segment_id": null,
+    "year": 606,
+    "year_label": "606",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_HARSHA:606:start",
+    "box_id": "SA_HARSHA",
+    "box_name": "Harsha's Empire",
+    "segment_id": null,
+    "year": 606,
+    "year_label": "606",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_HARSHA:647:end",
+    "box_id": "SA_HARSHA",
+    "box_name": "Harsha's Empire",
+    "segment_id": null,
+    "year": 647,
+    "year_label": "647",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_REGIONAL:647:start",
+    "box_id": "SA_REGIONAL",
+    "box_name": "Regional Kingdoms",
+    "segment_id": null,
+    "year": 647,
+    "year_label": "647",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_REGIONAL:1206:end",
+    "box_id": "SA_REGIONAL",
+    "box_name": "Regional Kingdoms",
+    "segment_id": null,
+    "year": 1206,
+    "year_label": "1206",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_DELHI:1206:start",
+    "box_id": "SA_DELHI",
+    "box_name": "Delhi Sultanate",
+    "segment_id": null,
+    "year": 1206,
+    "year_label": "1206",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_DELHI:1526:end",
+    "box_id": "SA_DELHI",
+    "box_name": "Delhi Sultanate",
+    "segment_id": null,
+    "year": 1526,
+    "year_label": "1526",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_MUGHAL:1526:start",
+    "box_id": "SA_MUGHAL",
+    "box_name": "Mughal Empire",
+    "segment_id": null,
+    "year": 1526,
+    "year_label": "1526",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_MUGHAL:1858:end",
+    "box_id": "SA_MUGHAL",
+    "box_name": "Mughal Empire",
+    "segment_id": null,
+    "year": 1858,
+    "year_label": "1858",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_COLONIAL_INDIA:1858:start",
+    "box_id": "SA_COLONIAL_INDIA",
+    "box_name": "Colonial India",
+    "segment_id": null,
+    "year": 1858,
+    "year_label": "1858",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "SA_COLONIAL_INDIA:1947:end",
+    "box_id": "SA_COLONIAL_INDIA",
+    "box_name": "Colonial India",
+    "segment_id": null,
+    "year": 1947,
+    "year_label": "1947",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PK_MODERN:1947:start",
+    "box_id": "PK_MODERN",
+    "box_name": "Pakistan",
+    "segment_id": null,
+    "year": 1947,
+    "year_label": "1947",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "PK_MODERN:2026:end",
+    "box_id": "PK_MODERN",
+    "box_name": "Pakistan",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IN_MODERN:1947:start",
+    "box_id": "IN_MODERN",
+    "box_name": "India",
+    "segment_id": null,
+    "year": 1947,
+    "year_label": "1947",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "IN_MODERN:2026:end",
+    "box_id": "IN_MODERN",
+    "box_name": "India",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_LIANGZHU:-3000:start",
+    "box_id": "CN_LIANGZHU",
+    "box_name": "Liangzhu Culture",
+    "segment_id": null,
+    "year": -3000,
+    "year_label": "c. 3000 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_LIANGZHU:-2070:end",
+    "box_id": "CN_LIANGZHU",
+    "box_name": "Liangzhu Culture",
+    "segment_id": null,
+    "year": -2070,
+    "year_label": "c. 2070 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_XIA:-2070:start",
+    "box_id": "CN_XIA",
+    "box_name": "Xia Dynasty",
+    "segment_id": null,
+    "year": -2070,
+    "year_label": "c. 2070 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_XIA:-1600:end",
+    "box_id": "CN_XIA",
+    "box_name": "Xia Dynasty",
+    "segment_id": null,
+    "year": -1600,
+    "year_label": "c. 1600 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_SHANG:-1600:start",
+    "box_id": "CN_SHANG",
+    "box_name": "Shang Dynasty",
+    "segment_id": null,
+    "year": -1600,
+    "year_label": "c. 1600 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_SHANG:-1046:end",
+    "box_id": "CN_SHANG",
+    "box_name": "Shang Dynasty",
+    "segment_id": null,
+    "year": -1046,
+    "year_label": "1046 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_ZHOU:-1046:start",
+    "box_id": "CN_ZHOU",
+    "box_name": "Zhou Dynasty",
+    "segment_id": null,
+    "year": -1046,
+    "year_label": "1046 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_ZHOU:-221:end",
+    "box_id": "CN_ZHOU",
+    "box_name": "Zhou Dynasty",
+    "segment_id": null,
+    "year": -221,
+    "year_label": "221 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_QIN:-221:start",
+    "box_id": "CN_QIN",
+    "box_name": "Qin Dynasty",
+    "segment_id": null,
+    "year": -221,
+    "year_label": "221 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_QIN:-202:end",
+    "box_id": "CN_QIN",
+    "box_name": "Qin Dynasty",
+    "segment_id": null,
+    "year": -202,
+    "year_label": "202 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_HAN:-202:start",
+    "box_id": "CN_HAN",
+    "box_name": "Han Dynasty",
+    "segment_id": null,
+    "year": -202,
+    "year_label": "202 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_HAN:220:end",
+    "box_id": "CN_HAN",
+    "box_name": "Han Dynasty",
+    "segment_id": null,
+    "year": 220,
+    "year_label": "220",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_DIVISION:220:start",
+    "box_id": "CN_DIVISION",
+    "box_name": "Age of Division",
+    "segment_id": null,
+    "year": 220,
+    "year_label": "220",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_DIVISION:589:end",
+    "box_id": "CN_DIVISION",
+    "box_name": "Age of Division",
+    "segment_id": null,
+    "year": 589,
+    "year_label": "589",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_SUI:589:start",
+    "box_id": "CN_SUI",
+    "box_name": "Sui Dynasty",
+    "segment_id": null,
+    "year": 589,
+    "year_label": "589",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_SUI:618:end",
+    "box_id": "CN_SUI",
+    "box_name": "Sui Dynasty",
+    "segment_id": null,
+    "year": 618,
+    "year_label": "618",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_TANG:618:start",
+    "box_id": "CN_TANG",
+    "box_name": "Tang Dynasty",
+    "segment_id": null,
+    "year": 618,
+    "year_label": "618",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_TANG:907:end",
+    "box_id": "CN_TANG",
+    "box_name": "Tang Dynasty",
+    "segment_id": null,
+    "year": 907,
+    "year_label": "907",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_FIVE:907:start",
+    "box_id": "CN_FIVE",
+    "box_name": "Five Dynasties Period",
+    "segment_id": null,
+    "year": 907,
+    "year_label": "907",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_FIVE:960:end",
+    "box_id": "CN_FIVE",
+    "box_name": "Five Dynasties Period",
+    "segment_id": null,
+    "year": 960,
+    "year_label": "960",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_SONG:960:start",
+    "box_id": "CN_SONG",
+    "box_name": "Song Dynasty",
+    "segment_id": null,
+    "year": 960,
+    "year_label": "960",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_SONG:1271:end",
+    "box_id": "CN_SONG",
+    "box_name": "Song Dynasty",
+    "segment_id": null,
+    "year": 1271,
+    "year_label": "1271",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_YUAN:1271:start",
+    "box_id": "CN_YUAN",
+    "box_name": "Yuan Dynasty",
+    "segment_id": null,
+    "year": 1271,
+    "year_label": "1271",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_YUAN:1368:end",
+    "box_id": "CN_YUAN",
+    "box_name": "Yuan Dynasty",
+    "segment_id": null,
+    "year": 1368,
+    "year_label": "1368",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_MING:1368:start",
+    "box_id": "CN_MING",
+    "box_name": "Ming Dynasty",
+    "segment_id": null,
+    "year": 1368,
+    "year_label": "1368",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_MING:1644:end",
+    "box_id": "CN_MING",
+    "box_name": "Ming Dynasty",
+    "segment_id": null,
+    "year": 1644,
+    "year_label": "1644",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_QING:1644:start",
+    "box_id": "CN_QING",
+    "box_name": "Qing Dynasty",
+    "segment_id": null,
+    "year": 1644,
+    "year_label": "1644",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_QING:1912:end",
+    "box_id": "CN_QING",
+    "box_name": "Qing Dynasty",
+    "segment_id": null,
+    "year": 1912,
+    "year_label": "1912",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_REPUBLIC:1912:start",
+    "box_id": "CN_REPUBLIC",
+    "box_name": "Republic of China",
+    "segment_id": null,
+    "year": 1912,
+    "year_label": "1912",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_REPUBLIC:1949:end",
+    "box_id": "CN_REPUBLIC",
+    "box_name": "Republic of China",
+    "segment_id": null,
+    "year": 1949,
+    "year_label": "1949",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_MODERN:1949:start",
+    "box_id": "CN_MODERN",
+    "box_name": "China",
+    "segment_id": null,
+    "year": 1949,
+    "year_label": "1949",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "CN_MODERN:2026:end",
+    "box_id": "CN_MODERN",
+    "box_name": "China",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_JOMON:-300:end",
+    "box_id": "JP_JOMON",
+    "box_name": "Jōmon Period",
+    "segment_id": null,
+    "year": -300,
+    "year_label": "c. 300 BCE",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_YAYOI:-300:start",
+    "box_id": "JP_YAYOI",
+    "box_name": "Yayoi Period",
+    "segment_id": null,
+    "year": -300,
+    "year_label": "c. 300 BCE",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_YAYOI:250:end",
+    "box_id": "JP_YAYOI",
+    "box_name": "Yayoi Period",
+    "segment_id": null,
+    "year": 250,
+    "year_label": "250",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_YAMATO:250:start",
+    "box_id": "JP_YAMATO",
+    "box_name": "Yamato State",
+    "segment_id": null,
+    "year": 250,
+    "year_label": "250",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_YAMATO:710:end",
+    "box_id": "JP_YAMATO",
+    "box_name": "Yamato State",
+    "segment_id": null,
+    "year": 710,
+    "year_label": "710",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_NARA:710:start",
+    "box_id": "JP_NARA",
+    "box_name": "Nara Period",
+    "segment_id": null,
+    "year": 710,
+    "year_label": "710",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_NARA:794:end",
+    "box_id": "JP_NARA",
+    "box_name": "Nara Period",
+    "segment_id": null,
+    "year": 794,
+    "year_label": "794",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_HEIAN:794:start",
+    "box_id": "JP_HEIAN",
+    "box_name": "Heian Period",
+    "segment_id": null,
+    "year": 794,
+    "year_label": "794",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_HEIAN:1185:end",
+    "box_id": "JP_HEIAN",
+    "box_name": "Heian Period",
+    "segment_id": null,
+    "year": 1185,
+    "year_label": "1185",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_KAMAKURA:1185:start",
+    "box_id": "JP_KAMAKURA",
+    "box_name": "Kamakura Shogunate",
+    "segment_id": null,
+    "year": 1185,
+    "year_label": "1185",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_KAMAKURA:1336:end",
+    "box_id": "JP_KAMAKURA",
+    "box_name": "Kamakura Shogunate",
+    "segment_id": null,
+    "year": 1336,
+    "year_label": "1336",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_MUROMACHI:1336:start",
+    "box_id": "JP_MUROMACHI",
+    "box_name": "Muromachi Shogunate",
+    "segment_id": null,
+    "year": 1336,
+    "year_label": "1336",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_MUROMACHI:1467:end",
+    "box_id": "JP_MUROMACHI",
+    "box_name": "Muromachi Shogunate",
+    "segment_id": null,
+    "year": 1467,
+    "year_label": "1467",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_SENGOKU:1467:start",
+    "box_id": "JP_SENGOKU",
+    "box_name": "Sengoku Period",
+    "segment_id": null,
+    "year": 1467,
+    "year_label": "c. 1467",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_SENGOKU:1603:end",
+    "box_id": "JP_SENGOKU",
+    "box_name": "Sengoku Period",
+    "segment_id": null,
+    "year": 1603,
+    "year_label": "1603",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_TOKUGAWA:1603:start",
+    "box_id": "JP_TOKUGAWA",
+    "box_name": "Tokugawa Shogunate",
+    "segment_id": null,
+    "year": 1603,
+    "year_label": "1603",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_TOKUGAWA:1868:end",
+    "box_id": "JP_TOKUGAWA",
+    "box_name": "Tokugawa Shogunate",
+    "segment_id": null,
+    "year": 1868,
+    "year_label": "1868",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_MEIJI:1868:start",
+    "box_id": "JP_MEIJI",
+    "box_name": "Meiji Era",
+    "segment_id": null,
+    "year": 1868,
+    "year_label": "1868",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_MEIJI:1912:end",
+    "box_id": "JP_MEIJI",
+    "box_name": "Meiji Era",
+    "segment_id": null,
+    "year": 1912,
+    "year_label": "1912",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_EMPIRE:1912:start",
+    "box_id": "JP_EMPIRE",
+    "box_name": "Empire of Japan",
+    "segment_id": null,
+    "year": 1912,
+    "year_label": "1912",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_EMPIRE:1947:end",
+    "box_id": "JP_EMPIRE",
+    "box_name": "Empire of Japan",
+    "segment_id": null,
+    "year": 1947,
+    "year_label": "1947",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_MODERN:1947:start",
+    "box_id": "JP_MODERN",
+    "box_name": "Japan",
+    "segment_id": null,
+    "year": 1947,
+    "year_label": "1947",
+    "sample_type": "start_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box start. Add/replace with a sourced population estimate."
+  },
+  {
+    "population_id": "JP_MODERN:2026:end",
+    "box_id": "JP_MODERN",
+    "box_name": "Japan",
+    "segment_id": null,
+    "year": 2026,
+    "year_label": "Present",
+    "sample_type": "end_boundary",
+    "population": null,
+    "log10_population": null,
+    "population_low": null,
+    "population_high": null,
+    "population_basis": "TBD",
+    "estimate_method": "TBD",
+    "source_url": null,
+    "source_citation": null,
+    "confidence": "Unknown",
+    "status": "TODO",
+    "notes": "Seed row at box end. Add/replace with a sourced population estimate."
+  }
+]
diff --git a/projects/world-history/data/regions.json b/projects/world-history/data/regions.json
new file mode 100644
index 0000000..c72ff70
--- /dev/null
+++ b/projects/world-history/data/regions.json
@@ -0,0 +1,625 @@
+[
+  {
+    "region_id": "NE_SCAND",
+    "region_name": "Northern Europe / Scandinavia",
+    "country": "Denmark",
+    "country_order": 1,
+    "notes": "Operational grouping uses the five Nordic sovereign states; broader than strict 'Scandinavia'."
+  },
+  {
+    "region_id": "NE_SCAND",
+    "region_name": "Northern Europe / Scandinavia",
+    "country": "Finland",
+    "country_order": 2,
+    "notes": null
+  },
+  {
+    "region_id": "NE_SCAND",
+    "region_name": "Northern Europe / Scandinavia",
+    "country": "Iceland",
+    "country_order": 3,
+    "notes": null
+  },
+  {
+    "region_id": "NE_SCAND",
+    "region_name": "Northern Europe / Scandinavia",
+    "country": "Norway",
+    "country_order": 4,
+    "notes": null
+  },
+  {
+    "region_id": "NE_SCAND",
+    "region_name": "Northern Europe / Scandinavia",
+    "country": "Sweden",
+    "country_order": 5,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Belarus",
+    "country_order": 1,
+    "notes": "Cultural/linguistic Slavic grouping spanning parts of Eastern, Central, and Southeastern Europe; not a strict UN geographic region."
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Bosnia and Herzegovina",
+    "country_order": 2,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Bulgaria",
+    "country_order": 3,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Croatia",
+    "country_order": 4,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Czechia",
+    "country_order": 5,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Montenegro",
+    "country_order": 6,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "North Macedonia",
+    "country_order": 7,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Poland",
+    "country_order": 8,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Russia",
+    "country_order": 9,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Serbia",
+    "country_order": 10,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Slovakia",
+    "country_order": 11,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Slovenia",
+    "country_order": 12,
+    "notes": null
+  },
+  {
+    "region_id": "EE_SLAVIC",
+    "region_name": "Eastern Europe / Slavic world",
+    "country": "Ukraine",
+    "country_order": 13,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Brunei",
+    "country_order": 1,
+    "notes": "Modern sovereign states conventionally grouped as Southeast Asia."
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Cambodia",
+    "country_order": 2,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Indonesia",
+    "country_order": 3,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Laos",
+    "country_order": 4,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Malaysia",
+    "country_order": 5,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Myanmar",
+    "country_order": 6,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Philippines",
+    "country_order": 7,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Singapore",
+    "country_order": 8,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Thailand",
+    "country_order": 9,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Timor-Leste",
+    "country_order": 10,
+    "notes": null
+  },
+  {
+    "region_id": "SE_ASIA",
+    "region_name": "Southeast Asia",
+    "country": "Vietnam",
+    "country_order": 11,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Bahrain",
+    "country_order": 1,
+    "notes": "Arabian Peninsula plus the core Levant. Iraq is not duplicated here because it already has a dedicated original-chart span."
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Israel",
+    "country_order": 2,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Jordan",
+    "country_order": 3,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Kuwait",
+    "country_order": 4,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Lebanon",
+    "country_order": 5,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Oman",
+    "country_order": 6,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Palestine",
+    "country_order": 7,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Qatar",
+    "country_order": 8,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Saudi Arabia",
+    "country_order": 9,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Syria",
+    "country_order": 10,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "United Arab Emirates",
+    "country_order": 11,
+    "notes": null
+  },
+  {
+    "region_id": "ARAB_LEVANT",
+    "region_name": "Arabia and the Levant",
+    "country": "Yemen",
+    "country_order": 12,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Angola",
+    "country_order": 1,
+    "notes": "Broad modern-country grouping; Sudan is kept with North Africa, while Mauritania is included with sub-Saharan/West Africa."
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Benin",
+    "country_order": 2,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Botswana",
+    "country_order": 3,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Burkina Faso",
+    "country_order": 4,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Burundi",
+    "country_order": 5,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Cabo Verde",
+    "country_order": 6,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Cameroon",
+    "country_order": 7,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Central African Republic",
+    "country_order": 8,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Chad",
+    "country_order": 9,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Comoros",
+    "country_order": 10,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Democratic Republic of the Congo",
+    "country_order": 11,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Djibouti",
+    "country_order": 12,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Equatorial Guinea",
+    "country_order": 13,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Eritrea",
+    "country_order": 14,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Eswatini",
+    "country_order": 15,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Ethiopia",
+    "country_order": 16,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Gabon",
+    "country_order": 17,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Gambia",
+    "country_order": 18,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Ghana",
+    "country_order": 19,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Guinea",
+    "country_order": 20,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Guinea-Bissau",
+    "country_order": 21,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Côte d’Ivoire",
+    "country_order": 22,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Kenya",
+    "country_order": 23,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Lesotho",
+    "country_order": 24,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Liberia",
+    "country_order": 25,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Madagascar",
+    "country_order": 26,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Malawi",
+    "country_order": 27,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Mali",
+    "country_order": 28,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Mauritania",
+    "country_order": 29,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Mauritius",
+    "country_order": 30,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Mozambique",
+    "country_order": 31,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Namibia",
+    "country_order": 32,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Niger",
+    "country_order": 33,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Nigeria",
+    "country_order": 34,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Republic of the Congo",
+    "country_order": 35,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Rwanda",
+    "country_order": 36,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "São Tomé and Príncipe",
+    "country_order": 37,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Senegal",
+    "country_order": 38,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Seychelles",
+    "country_order": 39,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Sierra Leone",
+    "country_order": 40,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Somalia",
+    "country_order": 41,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "South Africa",
+    "country_order": 42,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "South Sudan",
+    "country_order": 43,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Tanzania",
+    "country_order": 44,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Togo",
+    "country_order": 45,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Uganda",
+    "country_order": 46,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Zambia",
+    "country_order": 47,
+    "notes": null
+  },
+  {
+    "region_id": "SSA",
+    "region_name": "Sub-Saharan Africa",
+    "country": "Zimbabwe",
+    "country_order": 48,
+    "notes": null
+  }
+]
diff --git a/projects/world-history/data/seais.json b/projects/world-history/data/seais.json
new file mode 100644
index 0000000..44e9ed6
--- /dev/null
+++ b/projects/world-history/data/seais.json
@@ -0,0 +1,1413 @@
+[
+  {
+    "seai_id": "M01",
+    "name": "Moon Landing",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1969,
+    "year_label": "1969",
+    "box_id": "US_MODERN",
+    "box_name": "United States",
+    "span": "United States",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 1,
+    "historical_year": 1969,
+    "notes": "Apollo 11.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M02",
+    "name": "Digital Revolution",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1970,
+    "year_label": "c. 1970",
+    "box_id": "US_MODERN",
+    "box_name": "United States",
+    "span": "United States",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 2,
+    "historical_year": 1970,
+    "notes": "Representative plotting year for the chart's broad 'Digital Revolution' milestone.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M03",
+    "name": "Discovery of Insulin",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1921,
+    "year_label": "1921",
+    "box_id": "CA_MODERN",
+    "box_name": "Canada",
+    "span": "Canada",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 3,
+    "historical_year": 1921,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M04",
+    "name": "Maize Cultivation",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": -2000,
+    "year_label": "c. 2000 BCE",
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "Mexico",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 4,
+    "historical_year": -2000,
+    "notes": "Chart placement is near the start of the Mexico Indigenous Era; this is not the earliest archaeological domestication date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M05",
+    "name": "Maya Astronomy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 500,
+    "year_label": "c. 500",
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "Mexico",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 5,
+    "historical_year": 500,
+    "notes": "Representative plotting year for the chart milestone.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M06",
+    "name": "Tango",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1880,
+    "year_label": "c. 1880",
+    "box_id": "AR_MODERN",
+    "box_name": "Argentina",
+    "span": "Argentina",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 6,
+    "historical_year": 1880,
+    "notes": "Representative emergence date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M07",
+    "name": "Wi-Fi Innovation",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1992,
+    "year_label": "c. 1992",
+    "box_id": "AU_MODERN",
+    "box_name": "Australia",
+    "span": "Australia",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 7,
+    "historical_year": 1992,
+    "notes": "Representative CSIRO-era WLAN innovation date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M08",
+    "name": "Laws of Motion & Gravity",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1687,
+    "year_label": "1687",
+    "box_id": "UK_STUART",
+    "box_name": "Stuart Dynasty",
+    "span": "United Kingdom",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 8,
+    "historical_year": 1687,
+    "notes": "Newton's Principia.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M09",
+    "name": "Watt's Steam Engine",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1769,
+    "year_label": "1769",
+    "box_id": "UK_HANOVER",
+    "box_name": "Hanoverian Dynasty",
+    "span": "United Kingdom",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 9,
+    "historical_year": 1769,
+    "notes": "Watt's separate-condenser steam-engine patent era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M10",
+    "name": "Natural Selection",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1859,
+    "year_label": "1859",
+    "box_id": "UK_HANOVER",
+    "box_name": "Hanoverian Dynasty",
+    "span": "United Kingdom",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 10,
+    "historical_year": 1859,
+    "notes": "Publication of On the Origin of Species.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M11",
+    "name": "Route to India",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1498,
+    "year_label": "1498",
+    "box_id": "PT_KINGDOM",
+    "box_name": "Kingdom of Portugal",
+    "span": "Portugal",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 11,
+    "historical_year": 1498,
+    "notes": "Vasco da Gama reaches India by sea.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M12",
+    "name": "Discovery of the Americas",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1492,
+    "year_label": "1492",
+    "box_id": "ES_UNIFICATION",
+    "box_name": "Unification of Spain",
+    "span": "Spain",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 12,
+    "historical_year": 1492,
+    "notes": "Columbus's first Atlantic voyage.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M13",
+    "name": "Rights of Man",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1789,
+    "year_label": "1789",
+    "box_id": "FR_BOURBON",
+    "box_name": "Bourbon France",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 13,
+    "historical_year": 1789,
+    "notes": "Declaration of the Rights of Man and of the Citizen.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M14",
+    "name": "Metric System",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1792,
+    "year_label": "1792",
+    "box_id": "FR_UNNAMED_1792",
+    "box_name": "[Unlabeled France segment]",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 14,
+    "historical_year": 1792,
+    "notes": "Marker sits in the thin unlabeled French transition segment beginning in 1792.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M15",
+    "name": "Renaissance",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1494,
+    "year_label": "c. 1494",
+    "box_id": "IT_DIVIDED",
+    "box_name": "Age of Divided Italy",
+    "span": "Italy",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 15,
+    "historical_year": 1494,
+    "notes": "The chart marker is placed at the start of the Age of Divided Italy; Renaissance dating is conventionally broader.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M16",
+    "name": "Printing Press",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1450,
+    "year_label": "c. 1450",
+    "box_id": "DE_HRE",
+    "box_name": "Holy Roman Empire",
+    "span": "Germany",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 16,
+    "historical_year": 1450,
+    "notes": "Gutenberg-era movable-type printing.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M17",
+    "name": "Automobile",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1886,
+    "year_label": "1886",
+    "box_id": "DE_EMPIRE",
+    "box_name": "German Empire",
+    "span": "Germany",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 17,
+    "historical_year": 1886,
+    "notes": "Benz Patent-Motorwagen era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M18",
+    "name": "Theory of Relativity",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1905,
+    "year_label": "1905",
+    "box_id": "DE_EMPIRE",
+    "box_name": "German Empire",
+    "span": "Germany",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 18,
+    "historical_year": 1905,
+    "notes": "Einstein's special-relativity paper.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M19",
+    "name": "Classical Music",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1750,
+    "year_label": "c. 1750",
+    "box_id": "AT_HABSBURG",
+    "box_name": "Habsburg Austria",
+    "span": "Austria",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 19,
+    "historical_year": 1750,
+    "notes": "Representative plotting year for the Classical era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M20",
+    "name": "Olympic Games",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1896,
+    "year_label": "1896",
+    "box_id": "GR_KINGDOM1",
+    "box_name": "Kingdom of Greece",
+    "span": "Greece",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 20,
+    "historical_year": 1896,
+    "notes": "First modern Olympic Games in Athens.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M21",
+    "name": "Birth of Democracy",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": -508,
+    "year_label": "c. 508 BCE",
+    "box_id": "GR_CLASSICAL",
+    "box_name": "Classical Greek City-States",
+    "span": "Greece",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 21,
+    "historical_year": -508,
+    "notes": "Athenian democratic reforms.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M22",
+    "name": "Justinian Code",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 529,
+    "year_label": "529",
+    "box_id": "BYZANTINE",
+    "box_name": "Byzantine Empire",
+    "span": "Greece; Turkey; Egypt",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 22,
+    "historical_year": 529,
+    "notes": "Codification under Justinian I.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M23",
+    "name": "Pyramids",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": -2560,
+    "year_label": "c. 2560 BCE",
+    "box_id": "EG_OLD",
+    "box_name": "Old Kingdom",
+    "span": "Egypt",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 23,
+    "historical_year": -2560,
+    "notes": "Great Pyramid era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M24",
+    "name": "Code of Hammurabi",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": -1754,
+    "year_label": "c. 1754 BCE",
+    "box_id": "IQ_OLD_BAB",
+    "box_name": "Old Babylonian Kingdom",
+    "span": "Iraq",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 24,
+    "historical_year": -1754,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M25",
+    "name": "Yoga",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": -3000,
+    "year_label": "c. 3000 BCE",
+    "box_id": "SA_INDUS",
+    "box_name": "Indus Valley Civilization",
+    "span": "Pakistan; India",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 25,
+    "historical_year": -3000,
+    "notes": "Chart marker is placed high in the Indus Valley Civilization box; precise origins are debated.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M26",
+    "name": "The Concept of Zero",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 628,
+    "year_label": "628",
+    "box_id": "SA_HARSHA",
+    "box_name": "Harsha's Empire",
+    "span": "Pakistan; India",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 26,
+    "historical_year": 628,
+    "notes": "Brahmagupta's formal treatment of zero.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M27",
+    "name": "Papermaking",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 105,
+    "year_label": "105",
+    "box_id": "CN_HAN",
+    "box_name": "Han Dynasty",
+    "span": "China",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 27,
+    "historical_year": 105,
+    "notes": "Traditionally associated with Cai Lun.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M28",
+    "name": "Compass",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1044,
+    "year_label": "c. 1044",
+    "box_id": "CN_SONG",
+    "box_name": "Song Dynasty",
+    "span": "China",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 28,
+    "historical_year": 1044,
+    "notes": "Representative Song-era written description of a magnetic compass.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M29",
+    "name": "Lean Manufacturing",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1950,
+    "year_label": "c. 1950",
+    "box_id": "JP_MODERN",
+    "box_name": "Japan",
+    "span": "Japan",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 29,
+    "historical_year": 1950,
+    "notes": "Representative Toyota Production System era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "M30",
+    "name": "Bullet Train",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Milestone of Civilization",
+    "year": 1964,
+    "year_label": "1964",
+    "box_id": "JP_MODERN",
+    "box_name": "Japan",
+    "span": "Japan",
+    "icon_present": true,
+    "icon_type": "numbered_circle",
+    "icon_number": 30,
+    "historical_year": 1964,
+    "notes": "Opening of the Tōkaidō Shinkansen.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L01",
+    "name": "Mesa Verde",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1200,
+    "year_label": "c. 1200",
+    "box_id": "US_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "United States",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1200,
+    "notes": "Representative date for the major cliff-dwelling period.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L02",
+    "name": "Chaco Culture",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1050,
+    "year_label": "c. 1050",
+    "box_id": "US_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "United States",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1050,
+    "notes": "Representative peak-era date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L03",
+    "name": "Cahokia Mounds",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1100,
+    "year_label": "c. 1100",
+    "box_id": "US_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "United States",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1100,
+    "notes": "Representative peak-era date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L04",
+    "name": "Statue of Liberty",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1886,
+    "year_label": "1886",
+    "box_id": "US_MODERN",
+    "box_name": "United States",
+    "span": "United States",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1886,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L05",
+    "name": "Head-Smashed-In Buffalo Jump",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1000,
+    "year_label": "c. 1000",
+    "box_id": "CA_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "Canada",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1000,
+    "notes": "Single plotting year is representative; the site was used over millennia.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L06",
+    "name": "Parliament Hill",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1859,
+    "year_label": "1859",
+    "box_id": "CA_COLONIAL",
+    "box_name": "Colonial Canada",
+    "span": "Canada",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1859,
+    "notes": "Start of the original parliamentary complex construction era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L07",
+    "name": "Chichen Itza",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 600,
+    "year_label": "c. 600",
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "Mexico",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 600,
+    "notes": "Representative founding/flourishing date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L08",
+    "name": "Teotihuacan",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 200,
+    "year_label": "c. 200",
+    "box_id": "MX_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "Mexico",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 200,
+    "notes": "Representative flourishing date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L09",
+    "name": "Obelisk of Buenos Aires",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1936,
+    "year_label": "1936",
+    "box_id": "AR_MODERN",
+    "box_name": "Argentina",
+    "span": "Argentina",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1936,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L10",
+    "name": "Uluru",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": null,
+    "year_label": "Natural landmark",
+    "box_id": "AU_INDIG",
+    "box_name": "Indigenous Era",
+    "span": "Australia",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": null,
+    "notes": "No single historical construction year; retained as a chart landmark with null year.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L11",
+    "name": "Sydney Opera House",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1973,
+    "year_label": "1973",
+    "box_id": "AU_MODERN",
+    "box_name": "Australia",
+    "span": "Australia",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1973,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L12",
+    "name": "Stonehenge",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -2500,
+    "year_label": "c. 2500 BCE",
+    "box_id": "UK_CELTIC",
+    "box_name": "Celtic Era",
+    "span": "United Kingdom",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -2500,
+    "notes": "Representative late-Neolithic construction phase; predates the chart's Celtic framing.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L13",
+    "name": "Windsor Castle",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1070,
+    "year_label": "c. 1070",
+    "box_id": "UK_NORMAN",
+    "box_name": "Norman Dynasty",
+    "span": "United Kingdom",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1070,
+    "notes": "Founded shortly after the Norman Conquest.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L14",
+    "name": "Big Ben",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1859,
+    "year_label": "1859",
+    "box_id": "UK_HANOVER",
+    "box_name": "Hanoverian Dynasty",
+    "span": "United Kingdom",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1859,
+    "notes": "Clock/bell era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L15",
+    "name": "Dolmens of Antequera",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -3500,
+    "year_label": "c. 3500 BCE",
+    "box_id": "PT_TRIBES",
+    "box_name": "Lusitanians and Other Tribes",
+    "span": "Portugal",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -3500,
+    "notes": "Historical construction predates the dated Lusitanian box; the poster uses the landmark illustratively.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L16",
+    "name": "Jerónimos Monastery",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1502,
+    "year_label": "1502",
+    "box_id": "PT_KINGDOM",
+    "box_name": "Kingdom of Portugal",
+    "span": "Portugal",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1502,
+    "notes": "Construction began in the early 16th century.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L17",
+    "name": "Belém Tower",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1514,
+    "year_label": "1514",
+    "box_id": "PT_KINGDOM",
+    "box_name": "Kingdom of Portugal",
+    "span": "Portugal",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1514,
+    "notes": "Construction began 1514; completed 1519.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L18",
+    "name": "Cave of Altamira",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -14500,
+    "year_label": "c. 14,500 BCE",
+    "box_id": "ES_IBERIAN",
+    "box_name": "Iberian & Celtic Tribes",
+    "span": "Spain",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -14500,
+    "notes": "Paleolithic cave art greatly predates the chart's Iberian/Celtic box; included because it is explicitly labeled there.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L19",
+    "name": "Alhambra",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1238,
+    "year_label": "1238",
+    "box_id": "ES_LATE_RECON",
+    "box_name": "Late Reconquista",
+    "span": "Spain",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1238,
+    "notes": "Start of the Nasrid palace complex / chart boundary.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L20",
+    "name": "Sagrada Família",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1882,
+    "year_label": "1882",
+    "box_id": "ES_CONSTITUTIONAL",
+    "box_name": "Constitutional Era",
+    "span": "Spain",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1882,
+    "notes": "Construction began.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L21",
+    "name": "Lascaux Cave",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -17000,
+    "year_label": "c. 17,000 BCE",
+    "box_id": "FR_GAUL",
+    "box_name": "Gaul",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -17000,
+    "notes": "Paleolithic cave art predates the Gaul box; poster uses it illustratively.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L22",
+    "name": "Mont-Saint-Michel",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 708,
+    "year_label": "708",
+    "box_id": "FR_FRANKISH",
+    "box_name": "Frankish Kingdom",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 708,
+    "notes": "Traditional foundation of the first sanctuary.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L23",
+    "name": "Notre-Dame de Paris",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1163,
+    "year_label": "1163",
+    "box_id": "FR_KINGDOM",
+    "box_name": "Kingdom of France",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1163,
+    "notes": "Construction began.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L24",
+    "name": "Louvre Museum",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1190,
+    "year_label": "c. 1190",
+    "box_id": "FR_KINGDOM",
+    "box_name": "Kingdom of France",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1190,
+    "notes": "Uses the original Louvre fortress construction as the plotting date; museum opened much later.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L25",
+    "name": "Palace of Versailles",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1682,
+    "year_label": "1682",
+    "box_id": "FR_BOURBON",
+    "box_name": "Bourbon France",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1682,
+    "notes": "Court moved to Versailles; construction began earlier.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L26",
+    "name": "Eiffel Tower",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1889,
+    "year_label": "1889",
+    "box_id": "FR_REPUBLICAN",
+    "box_name": "Republican France",
+    "span": "France",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1889,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L27",
+    "name": "Temple of Saturn",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -497,
+    "year_label": "c. 497 BCE",
+    "box_id": "ROMAN_REPUBLIC",
+    "box_name": "Roman Republic",
+    "span": "Portugal; Spain; France; Italy; Greece; Turkey",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -497,
+    "notes": "Traditional dedication date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L28",
+    "name": "Colosseum",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 80,
+    "year_label": "80",
+    "box_id": "ROMAN_EMPIRE",
+    "box_name": "Roman Empire",
+    "span": "United Kingdom; Portugal; Spain; France; Italy; Germany; Austria; Greece; Turkey; Egypt",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 80,
+    "notes": "Completion/inauguration era.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L29",
+    "name": "Roman Forum",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 100,
+    "year_label": "c. 100",
+    "box_id": "ROMAN_EMPIRE",
+    "box_name": "Roman Empire",
+    "span": "United Kingdom; Portugal; Spain; France; Italy; Germany; Austria; Greece; Turkey; Egypt",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 100,
+    "notes": "The Forum developed over many centuries; 100 CE is a representative plotting year consistent with the poster's placement.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L30",
+    "name": "Leaning Tower of Pisa",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1173,
+    "year_label": "1173",
+    "box_id": "IT_MEDIEVAL_STATES",
+    "box_name": "Medieval Italian States",
+    "span": "Italy",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1173,
+    "notes": "Construction began.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L31",
+    "name": "Cologne Cathedral",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1248,
+    "year_label": "1248",
+    "box_id": "DE_HRE",
+    "box_name": "Holy Roman Empire",
+    "span": "Germany",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1248,
+    "notes": "Construction began.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L32",
+    "name": "Brandenburg Gate",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1791,
+    "year_label": "1791",
+    "box_id": "DE_HRE",
+    "box_name": "Holy Roman Empire",
+    "span": "Germany",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1791,
+    "notes": "Completed 1791.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L33",
+    "name": "St. Stephen's Cathedral",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1147,
+    "year_label": "1147",
+    "box_id": "AT_MARGRAVIATE",
+    "box_name": "Margraviate of Austria",
+    "span": "Austria",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1147,
+    "notes": "Early church dedication; later Gothic rebuilding.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L34",
+    "name": "Schönbrunn Palace",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1740,
+    "year_label": "c. 1740",
+    "box_id": "AT_HABSBURG",
+    "box_name": "Habsburg Austria",
+    "span": "Austria",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1740,
+    "notes": "Representative mid-18th-century rebuilding/imperial-palace date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L35",
+    "name": "Parthenon",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -438,
+    "year_label": "438 BCE",
+    "box_id": "GR_CLASSICAL",
+    "box_name": "Classical Greek City-States",
+    "span": "Greece",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -438,
+    "notes": "Completed c. 438 BCE.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L36",
+    "name": "Hagia Sophia",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 537,
+    "year_label": "537",
+    "box_id": "BYZANTINE",
+    "box_name": "Byzantine Empire",
+    "span": "Greece; Turkey; Egypt",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 537,
+    "notes": "Current structure completed under Justinian I.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L37",
+    "name": "Blue Mosque",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1616,
+    "year_label": "1616",
+    "box_id": "OTTOMAN",
+    "box_name": "Ottoman Empire",
+    "span": "Greece; Turkey; Egypt; Iraq",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1616,
+    "notes": "Completed 1616.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L38",
+    "name": "Great Pyramid of Giza",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -2560,
+    "year_label": "c. 2560 BCE",
+    "box_id": "EG_OLD",
+    "box_name": "Old Kingdom",
+    "span": "Egypt",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -2560,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L39",
+    "name": "Karnak",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -2000,
+    "year_label": "c. 2000 BCE",
+    "box_id": "EG_MIDDLE",
+    "box_name": "Middle Kingdom",
+    "span": "Egypt",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -2000,
+    "notes": "Representative early major construction phase.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L40",
+    "name": "Abu Simbel",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -1264,
+    "year_label": "c. 1264 BCE",
+    "box_id": "EG_NEW",
+    "box_name": "New Kingdom",
+    "span": "Egypt",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -1264,
+    "notes": "Construction under Ramesses II.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L41",
+    "name": "Ziggurat of Ur",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -2100,
+    "year_label": "c. 2100 BCE",
+    "box_id": "IQ_SUMER_REN",
+    "box_name": "Sumerian Renaissance",
+    "span": "Iraq",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -2100,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L42",
+    "name": "Choqha Zanbil",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -1250,
+    "year_label": "c. 1250 BCE",
+    "box_id": "IR_TRIBES",
+    "box_name": "Iranian Tribes",
+    "span": "Iran",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -1250,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L43",
+    "name": "Persepolis",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -515,
+    "year_label": "c. 515 BCE",
+    "box_id": "PERSIAN",
+    "box_name": "Persian Empire",
+    "span": "Turkey; Egypt; Iraq; Iran; Pakistan; India",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -515,
+    "notes": "Construction began under Darius I.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L44",
+    "name": "Naqsh-e Jahan Square",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1602,
+    "year_label": "c. 1602",
+    "box_id": "IR_SAFAVID",
+    "box_name": "Safavid Empire",
+    "span": "Iran",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1602,
+    "notes": "Safavid-era construction.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L45",
+    "name": "Mohenjo-daro",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -2500,
+    "year_label": "c. 2500 BCE",
+    "box_id": "SA_INDUS",
+    "box_name": "Indus Valley Civilization",
+    "span": "Pakistan; India",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -2500,
+    "notes": "Representative mature Harappan phase.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L46",
+    "name": "Taxila",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -600,
+    "year_label": "c. 600 BCE",
+    "box_id": "SA_VEDIC",
+    "box_name": "Vedic Period",
+    "span": "Pakistan; India",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -600,
+    "notes": "Representative early urban/learning-center date; the site spans multiple periods.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L47",
+    "name": "Qutub Minar",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1220,
+    "year_label": "c. 1220",
+    "box_id": "SA_DELHI",
+    "box_name": "Delhi Sultanate",
+    "span": "Pakistan; India",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1220,
+    "notes": "Representative completion of the early tower stages.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L48",
+    "name": "Taj Mahal",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1653,
+    "year_label": "1653",
+    "box_id": "SA_MUGHAL",
+    "box_name": "Mughal Empire",
+    "span": "Pakistan; India",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1653,
+    "notes": "Completion date.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L49",
+    "name": "Great Wall of China",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -700,
+    "year_label": "c. 700 BCE",
+    "box_id": "CN_ZHOU",
+    "box_name": "Zhou Dynasty",
+    "span": "China",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -700,
+    "notes": "Representative early wall-building era; later dynasties rebuilt extensively.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L50",
+    "name": "Terracotta Army",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": -210,
+    "year_label": "c. 210 BCE",
+    "box_id": "CN_QIN",
+    "box_name": "Qin Dynasty",
+    "span": "China",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": -210,
+    "notes": "Qin Shi Huang mausoleum complex.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L51",
+    "name": "Forbidden City",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1420,
+    "year_label": "1420",
+    "box_id": "CN_MING",
+    "box_name": "Ming Dynasty",
+    "span": "China",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1420,
+    "notes": "Completed 1420.",
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L52",
+    "name": "Kinkaku-ji",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1397,
+    "year_label": "1397",
+    "box_id": "JP_MUROMACHI",
+    "box_name": "Muromachi Shogunate",
+    "span": "Japan",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1397,
+    "notes": null,
+    "confidence": "High"
+  },
+  {
+    "seai_id": "L53",
+    "name": "Himeji Castle",
+    "url": "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals",
+    "category": "Historical Landmark",
+    "year": 1609,
+    "year_label": "1609",
+    "box_id": "JP_TOKUGAWA",
+    "box_name": "Tokugawa Shogunate",
+    "span": "Japan",
+    "icon_present": true,
+    "icon_type": "landmark_icon",
+    "icon_number": null,
+    "historical_year": 1609,
+    "notes": "Major early-Edo reconstruction completed.",
+    "confidence": "High"
+  }
+]
diff --git a/projects/world-history/docs/DATA_MODEL.md b/projects/world-history/docs/DATA_MODEL.md
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--- /dev/null
+++ b/projects/world-history/docs/DATA_MODEL.md
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+# Data Model
+
+## Design goals
+
+The model should support poster-style chronology, filtering by modern-country alignment, alluvial/Sankey succession, population-dependent widths, SEAIs, uncertainty, and future geographic refinement.
+
+The Excel workbook remains the editable source of truth.
+
+# 1. Boxes
+
+A **Box** represents one labeled historical entity or era from the source poster.
+
+Examples:
+
+- Roman Empire
+- Byzantine Empire
+- Han Dynasty
+- Kingdom of France
+- Colonial America
+
+Primary key: `box_id`
+
+Important fields:
+
+| Field | Meaning |
+|---|---|
+| `box_id` | Stable machine-readable identifier |
+| `box_name` | Display name |
+| `url` | Wikipedia URL or TODO placeholder |
+| `start_year` | Numeric plotting year; BCE negative |
+| `end_year` | Numeric plotting year |
+| `start_label` | Human-readable source-style label |
+| `end_label` | Human-readable source-style label |
+| `color_name` | Palette category |
+| `color_hex` | Poster color |
+| `span` | Semicolon-delimited modern-country alignment |
+| `region_group` | Broad grouping |
+| `notes` | Exceptions / interpretation |
+| `confidence` | Confidence in transcription |
+
+## Year convention
+
+BCE years are negative:
+
+```text
+500 BCE -> -500
+27 BCE  -> -27
+```
+
+CE years are positive.
+
+There is no attempt to model a historical year zero.
+
+`Present` is currently represented numerically as 2026 while retaining `Present` in the label field.
+
+# 2. SEAIs
+
+SEAI means **Significant Event / Architectural Item**.
+
+SEAIs are intentionally separate from boxes.
+
+Current categories:
+
+- `Milestone of Civilization`
+- `Historical Landmark`
+
+Primary key: `seai_id`
+
+Foreign key:
+
+```text
+box_id -> Boxes.box_id
+```
+
+Important fields include name, URL, category, plotting year, parent box, icon metadata, historical year, notes, and confidence.
+
+# 3. Population
+
+Population is a **time series**, not a scalar property of a box.
+
+Primary key: `population_id`
+
+Foreign keys:
+
+```text
+box_id     -> Boxes.box_id
+segment_id -> BoxSegments.segment_id   (optional / future)
+```
+
+Current proposed fields:
+
+| Field | Meaning |
+|---|---|
+| `population_id` | Unique row identifier |
+| `box_id` | Historical entity |
+| `box_name` | Convenience display field |
+| `segment_id` | Optional geographic segment |
+| `year` | Knot-point year |
+| `year_label` | Display label |
+| `sample_type` | Boundary, census, event, breakpoint |
+| `population` | Best estimate |
+| `log10_population` | Derived value |
+| `population_low` | Lower estimate |
+| `population_high` | Upper estimate |
+| `population_basis` | What population means |
+| `estimate_method` | How estimate was produced |
+| `source_url` | Direct source |
+| `source_citation` | Citation text |
+| `confidence` | High / Medium / Low / Unknown |
+| `status` | TODO / Estimated / Verified |
+| `notes` | Caveats |
+
+Recommended `population_basis` values:
+
+- `polity_total`
+- `territorial_segment`
+- `modern_country_total`
+- `other`
+
+If the Roman Empire has an estimate of 60M, that should generally be one `polity_total` estimate, not 60M duplicated into every modern-country lane.
+
+Prefer sparse, meaningful knot points rather than annual rows.
+
+Good knots include:
+
+- box start;
+- box end;
+- census;
+- plague;
+- conquest;
+- territorial split;
+- demographic collapse;
+- expansion;
+- benchmark year.
+
+Interpolation can occur at build/render time.
+
+# 4. Regions
+
+`Regions` is currently a modern-country grouping table for omitted areas.
+
+Current groupings:
+
+- Northern Europe / Scandinavia
+- Eastern Europe / Slavic world
+- Southeast Asia
+- Arabia and the Levant
+- Sub-Saharan Africa
+
+This is an intermediate model, not a claim that all five are formal geographic/cultural ontologies.
+
+# 5. Proposed: Links
+
+This table is required for serious Sankey/alluvial work.
+
+A Link documents a relationship between historical boxes.
+
+Proposed fields:
+
+| Field | Meaning |
+|---|---|
+| `link_id` | Unique identifier |
+| `source_box_id` | Source entity |
+| `target_box_id` | Target entity |
+| `year` | Transition/relationship year |
+| `relation_type` | Nature of relationship |
+| `weight_basis` | How link width should be computed |
+| `confidence` | Confidence |
+| `source_url` | Supporting source |
+| `notes` | Interpretation |
+
+Recommended relation types:
+
+- `successor`
+- `partition`
+- `unification`
+- `conquest`
+- `colonization`
+- `decolonization`
+- `dynastic_transition`
+- `institutional_successor`
+- `cultural_continuity`
+- `migration`
+- `other`
+
+Example:
+
+| source | target | year | relation |
+|---|---|---:|---|
+| Roman Empire | Western Roman Empire | 395 | partition |
+| Roman Empire | Byzantine Empire | 395 | partition |
+| Frankish Kingdom | West Francia | 843 | partition |
+| East Francia | Holy Roman Empire | 962 | institutional_successor |
+
+Not every chronological adjacency should automatically become a link.
+
+# 6. Proposed: BoxSegments
+
+`BoxSegments` should normalize the current `span` representation.
+
+A BoxSegment represents one historical entity occupying one modern-country lane over one time interval.
+
+Proposed fields:
+
+| Field | Meaning |
+|---|---|
+| `segment_id` | Unique identifier |
+| `box_id` | Parent box |
+| `modern_country` | Modern-country alignment |
+| `start_year` | Segment start |
+| `end_year` | Segment end |
+| `confidence` | Confidence |
+| `notes` | Caveat |
+
+This solves step-shaped poster boxes, differing start/end dates across modern-country lanes, geographic filtering, population allocation, and better alluvial layouts.
+
+# 7. Generated JSON
+
+Suggested outputs:
+
+```text
+data/
+├── boxes.json
+├── seais.json
+├── population.json
+├── regions.json
+├── links.json
+└── box-segments.json
+```
+
+The build process should validate all IDs and foreign keys.
+
+# 8. Validation rules
+
+At minimum:
+
+Implemented in `tools/wh_data.py`. That implementation splits these rules into
+two severities: **ERROR** (structural — duplicate/missing ID, broken foreign
+key, malformed year, invalid numeric population, inconsistent low/high
+bounds; fails the build) and **WARNING** (content-quality — TODO URLs,
+missing population, off-vocabulary confidence/status/basis values, duplicate
+knot points; reported but does not block the build). Where a rule below
+doesn't say which, treat "unique"/"exists"/"malformed"/"invalid numeric" as
+ERROR and "controlled vocabulary" as WARNING, since the workbook is expected
+to be ahead of the documented vocabularies at this stage.
+
+### Boxes
+
+- `box_id` unique;
+- `start_year <= end_year` when both exist;
+- valid color hex;
+- controlled confidence vocabulary.
+
+### SEAIs
+
+- `seai_id` unique;
+- every `box_id` exists;
+- event year numeric when present;
+- TODO Wikipedia URLs recognizable.
+
+### Population
+
+- every `box_id` exists;
+- `population > 0` when populated;
+- `population_low <= population <= population_high`;
+- duplicate knot points flagged;
+- controlled basis/method vocabulary.
+
+### Links
+
+- source and target boxes exist;
+- relation type valid;
+- transition year sensible.
+
+### BoxSegments
+
+- parent box exists;
+- dates fall reasonably within parent box envelope;
+- modern country exists in vocabulary.
+
+# 9. Preserve uncertainty
+
+Do not silently clean up ambiguous history.
+
+Store source, confidence, low/high population, approximate labels, and notes.
+
+The visual layer can decide how uncertainty is displayed.
diff --git a/projects/world-history/docs/IMPLEMENTATION_PLAN.md b/projects/world-history/docs/IMPLEMENTATION_PLAN.md
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+# Implementation Plan
+
+## Objective
+
+Build a graphically rich, interactive, static world-history explorer and deploy it through GitHub Pages.
+
+No production server is required.
+
+The existing contents of `erikson1970.github.io` may be replaced.
+
+# Phase 0 — Repository reset
+
+- inspect current repository;
+- preserve anything worth keeping only if desired;
+- replace test content with a clean project structure;
+- add a source-data directory for spreadsheets;
+- add project documentation.
+
+Suggested tree:
+
+```text
+/
+├── index.html
+├── css/
+├── js/
+├── data/
+├── source/
+├── tools/
+└── docs/
+```
+
+# Phase 1 — Data build pipeline
+
+## Goal
+
+Convert Excel workbook tables to validated JSON.
+
+Suggested tool: Python.
+
+Recommended libraries:
+
+- `openpyxl` or `pandas`;
+- built-in `json`;
+- optional `pydantic`.
+
+Suggested script:
+
+```text
+tools/build_data.py
+```
+
+Inputs:
+
+```text
+source/*.xlsx
+```
+
+Outputs:
+
+```text
+data/boxes.json
+data/seais.json
+data/population.json
+data/regions.json
+```
+
+Later:
+
+```text
+data/links.json
+data/box-segments.json
+```
+
+Fail the build on duplicate IDs, broken foreign keys, malformed years, invalid numeric population, inconsistent low/high bounds, and invalid relation types.
+
+Warn on TODO Wikipedia URLs, missing population, low-confidence records, and suspicious dates.
+
+# Phase 2 — Minimal static application
+
+Suggested shared state:
+
+```javascript
+{
+  selectedBoxId: null,
+  selectedSeaiId: null,
+  regionFilter: "all",
+  countryFilter: "all",
+  yearStart: -3000,
+  yearEnd: 2026,
+  widthMode: "equal",
+  showSeais: true
+}
+```
+
+Separate data loading, state management, and rendering.
+
+# Phase 3 — Plotly alluvial prototype
+
+Use a small subset first.
+
+Good candidates:
+
+### Mediterranean / Europe
+
+- Roman Empire;
+- Western Roman Empire;
+- Byzantine Empire;
+- Frankish Kingdom;
+- West Francia;
+- Kingdom of France;
+- East Francia;
+- Holy Roman Empire;
+- Ottoman Empire.
+
+### China
+
+- Zhou;
+- Qin;
+- Han;
+- Age of Division;
+- Sui;
+- Tang;
+- Five Dynasties;
+- Song;
+- Yuan;
+- Ming;
+- Qing.
+
+Create a minimal `Links` table for the chosen subset.
+
+Acceptance criteria:
+
+- nodes ordered chronologically;
+- links clickable;
+- selected node updates inspector;
+- page remains static.
+
+# Phase 4 — Timeline view
+
+Render source-poster-inspired boxes from `Boxes`.
+
+Likely renderer: SVG + D3.
+
+Initial version may use current `span` approximately and defer exact `BoxSegments`.
+
+Acceptance criteria:
+
+- boxes appear at correct dates;
+- colors match source data;
+- click selection works;
+- date zoom/filter works;
+- SEAIs can be overlaid.
+
+# Phase 5 — Shared interaction
+
+Synchronize Sankey, timeline, and inspector.
+
+Selecting one entity anywhere should update every panel.
+
+Possible future deep link:
+
+```text
+?box=BYZANTINE&year=537
+```
+
+# Phase 5.5 — Semantic zoom time scale
+
+Full spec: `docs/timescaleRequirement.md` (added 2026-09-07).
+
+Replace the timeline's plain linear year→x mapping with a nonlinear
+"semantic zoom" scale that gives recent history progressively more
+horizontal room as the visible span widens, and relaxes toward linear as
+the view narrows:
+
+```text
+p = 1 / (1 + (M / 3000) * 2^s)
+x = 1 - (a / M)^p
+```
+
+where `M` is the visible year span, `a` is an event's age relative to the
+right edge of the viewport, and `s` is a user-adjustable scale parameter.
+
+Implement as a reusable module (`semanticTimeScale({ tMin, tMax, scaler })`
+returning `yearToX`/`xToYear`/`exponent`), not baked into `timeline.js`
+directly — every time-based visual element in a view (box start/end,
+SEAIs, event markers, succession transitions, Sankey/alluvial node
+placement, population knot points, tick locations) must share the same
+transform; no mixing linear and semantic placement within one view.
+
+User control: a single slider, range `[-2, 2]`, default `0` ("Ancient
+detail ↔ Recent detail"); the raw exponent stays internal, not exposed in
+the UI.
+
+Should land before Phase 6 (population knot points must sit on the same
+scale) and revisits Phase 3's Sankey x-positioning and Phase 4's timeline
+x-positioning, both currently linear.
+
+Acceptance criteria (see `docs/timescaleRequirement.md` for full
+derivations):
+
+- `yearToX(tMin) == 0`, `yearToX(tMax) == 1`;
+- monotonic for any `t1 < t2`, any valid `M`/`s`;
+- round-trips (`xToYear(yearToX(t)) ≈ t`);
+- depends only on `[tMin, tMax, s]` — never on SEAI/box/population
+  filtering or density;
+- ticks generated in calendar time, then transformed (not evenly spaced
+  screen ticks reverse-mapped);
+- updates interactively (slider drag, zoom) without a full page reload.
+
+# Phase 6 — Population experiment
+
+Populate only enough data to test width encodings.
+
+Target roughly 10–20 important boxes with a few knot points each.
+
+Support:
+
+- equal;
+- raw population;
+- `log10(population)`;
+- square root.
+
+Questions:
+
+- Is raw population usable?
+- Does `log10` compress too much?
+- Is square root a better compromise?
+- Is a minimum visual width needed?
+
+# Phase 7 — BoxSegments
+
+Normalize complex multi-country boxes.
+
+Start with:
+
+- Roman Empire;
+- Persian Empire;
+- Byzantine Empire;
+- Arab Caliphate;
+- Ottoman Empire;
+- First French Empire.
+
+# Phase 8 — Expand omitted regions
+
+Current intermediate groups:
+
+- Northern Europe / Scandinavia;
+- Eastern Europe / Slavic world;
+- Southeast Asia;
+- Arabia and the Levant;
+- Sub-Saharan Africa.
+
+Recommended development order:
+
+1. Northern Europe / Scandinavia
+2. Eastern Europe / Slavic world
+3. Arabia and Levant
+4. Southeast Asia
+5. Sub-Saharan Africa
+
+This is only a development sequence, not a statement of historical importance.
+
+# Phase 9 — Static deployment
+
+Production should require only:
+
+```text
+HTML
+CSS
+JavaScript
+JSON
+```
+
+No Python executes in production.
+
+Python is build/preprocessing only.
+
+# Development principles
+
+1. Build visualization before perfecting the ontology.
+2. Stable IDs matter.
+3. Preserve uncertainty.
+4. Separate source data from generated data.
+5. Keep browser stateless initially.
+6. Prefer inspectable code over framework complexity.
+
+# Suggested first coding session
+
+1. Reset repo into clean project structure.
+2. Copy spreadsheet(s) into `source/`.
+3. Implement `build_data.py`.
+4. Generate JSON.
+5. Render a simple list/count sanity-check page.
+6. Add a small hand-authored `links.json`.
+7. Render first Plotly Sankey.
+8. Add click-to-inspector behavior.
+9. Commit.
+
+At that point the project will have crossed the important boundary from “dataset” to “interactive application.”
diff --git a/projects/world-history/docs/STATUS.md b/projects/world-history/docs/STATUS.md
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--- /dev/null
+++ b/projects/world-history/docs/STATUS.md
@@ -0,0 +1,192 @@
+# Project Status
+
+## Status summary
+
+**Phase:** data transcription complete enough for visualization prototyping; a validated build pipeline (`tools/build_data.py`) now converts the workbook into the `data/*.json` the site actually loads. A minimal `Links` table now exists for a small Mediterranean/Europe subset, and a first Sankey/alluvial prototype renders it (Phase 3). A first D3 timeline view (Phase 4) now sits above it, and selection is now synchronized across every panel (Phase 5). A shared, nonlinear semantic-zoom time scale (`docs/timescaleRequirement.md`, Phase 5.5) now drives x-position in both the timeline and the alluvial diagram.
+
+The project currently has a usable first-pass dataset derived from the ChartOrigin *Timeline of World History* poster.
+
+`data/*.json` is generated, not authored, and must never be hand-edited — see `data/README.md`/`tools/README.md`. Re-run `python3 tools/build_data.py` after any workbook edit; it fails (writes nothing) on structural problems and warns on content-quality gaps (see `docs/DATA_MODEL.md` §8).
+
+A first interactive prototype now exists (`index.html` + `js/`): load the generated JSON, list all `Boxes` sorted chronologically with color swatches, click one to see an inspector panel, filter by `region_group`. This satisfies "Build first interactive prototype" below; a first Phase 4 timeline view now exists too (see below), though it still lacks population-based width and the poster's own lane geometry.
+
+A Phase 3 alluvial prototype (`js/sankey.js`, Plotly loaded from CDN) sits above the box list: a small hand-authored 7-row `Links` subset (Roman → Western Roman/Byzantine, Frankish → West/East Francia, West Francia → Kingdom of France, East Francia → Holy Roman Empire, Byzantine → Ottoman) renders as a Sankey diagram with nodes ordered chronologically by `start_year` (`arrangement: "fixed"`, no auto-layout reordering). Clicking a node or link updates the same inspector panel as the box list. Ribbon width is currently equal-weighted, not population-based (see ISSUE-003).
+
+A Phase 4 timeline prototype (`js/timeline.js`, D3 loaded from CDN) sits above the alluvial diagram: one horizontal bar per box currently in view (region + year-range filtered), ordered chronologically, colored by `color_hex`, with diamond markers overlaying SEAIs. "From year"/"To year" number inputs drive the year-range filter (`state.yearStart`/`yearEnd`); a checkbox toggles the SEAI overlay (`state.showSeais`). Clicking a bar selects the same shared `selectedBoxId` as the box list, which remains the sole keyboard-accessible way to make that selection — the timeline SVG itself has no independent hidden fallback list, since (unlike the Sankey links) every box it draws is already reachable through the box list. The six boxes with no legible start date on the source poster (ISSUE-005) are drawn with a dashed left edge running to the current view's left boundary, not a fabricated date. Bar width is still literal poster start/end year, not population-based (`state.widthMode` exists in `js/state.js` but has no UI control yet — deferred, since `Population` is still 0% filled, ISSUE-003).
+
+Phase 5 synchronizes selection across every panel: the box list, alluvial list, Sankey diagram, and timeline all stay consistent no matter where a box or link is selected. The Sankey diagram and timeline don't have a `selectedLinkId`/`selectedBoxId` field of their own — a selected box gets an outline (Sankey node border, timeline bar stroke), and a selected link's two endpoint boxes get an outline (Sankey `link.color`, timeline `.link-endpoint`), all applied via `js/app.js` re-deriving the highlight on every store change, not by the Sankey/timeline modules knowing about each other.
+
+Phase 5.5 (`docs/timescaleRequirement.md`) replaces the timeline's plain linear x-axis with a shared, pure, Node-testable "semantic zoom" scale (`js/timescale.js`'s `semanticTimeScale`/`timeTicks`): `x = 1 - (a/M)^p`, where `p` is driven by both the visible span (`state.yearStart`/`yearEnd`) and a new "Time compression" slider (`state.timeScale`, range [-2, 2], default 0). The same scale instance/domain now positions timeline bars, SEAI markers, axis ticks, *and* the Sankey diagram's node x-position (`js/sankey.js`'s `computeSankeyNodeX`) — dragging the slider or the year-range inputs updates both views together, continuously (bound to the slider's `input` event, not `change`). The Sankey diagram's node *set* is still driven only by `data/links.json`, unfiltered by year range — only where each node lands on the x-axis changed. Axis labels are now explicit "N BCE"/"N CE" instead of a raw signed number. Smoothly animating the transition while dragging (optional per the spec) was not implemented — see `ISSUES.md`.
+
+Canonical poster/source page:
+
+- https://chartorigin.com/product/timeline-of-world-history/
+
+## Completed
+
+### Historical boxes
+
+The poster has been transcribed into a `Boxes` table.
+
+Current count: **198 boxes**
+
+Current fields include:
+
+- `box_id`
+- `box_name`
+- `url`
+- `start_year`
+- `end_year`
+- `start_label`
+- `end_label`
+- `color_name`
+- `color_hex`
+- `span`
+- `span_count`
+- `span_start`
+- `span_end`
+- `region_group`
+- `notes`
+- `confidence`
+
+### SEAIs
+
+Significant events / architectural items are stored separately.
+
+Current count: **83 SEAIs**
+
+- 30 numbered civilization milestones;
+- 53 labeled historical landmarks / architectural items.
+
+### Wikipedia URL placeholders
+
+Both `Boxes` and `SEAIs` include a URL field.
+
+The intentionally bogus/TODO placeholder is:
+
+```text
+https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals
+```
+
+Do not interpret that URL as meaningful data.
+
+### Population scaffold
+
+A separate `Population` table exists.
+
+Current count: **390 seeded rows**
+
+Rows were seeded at known box start/end boundaries.
+
+Population values were deliberately **not invented**.
+
+The table is designed to hold historical knot points with estimate, low/high range, basis, method, source, confidence, and status.
+
+### Added missing regional groupings
+
+A `Regions` table currently includes five intermediate regional groupings not covered well by the source poster:
+
+1. Northern Europe / Scandinavia
+2. Eastern Europe / Slavic world
+3. Southeast Asia
+4. Arabia and the Levant
+5. Sub-Saharan Africa
+
+These currently function as modern-country grouping metadata, not yet as full historical timelines.
+
+Current region-country rows: **89**
+
+## Important known limitations
+
+### 1. The original poster is selective
+
+It is not a complete world history.
+
+Major omissions include, among others:
+
+- Scandinavia / Nordics;
+- Eastern Europe / Slavic histories;
+- Korea;
+- Southeast Asia;
+- Arabia and the Levant;
+- Central Asia;
+- most of Sub-Saharan Africa;
+- much of North Africa west of Egypt;
+- Brazil;
+- Andes;
+- Central America / Caribbean;
+- Oceania beyond Australia;
+- Low Countries;
+- Switzerland.
+
+The five requested regions above are the first extension step.
+
+### 2. Some dates are approximate
+
+The poster itself contains approximate dates, very thin transition boxes, step-shaped multi-country boxes, and some labels that are difficult to read at image resolution.
+
+The dataset preserves uncertainty in `notes` and `confidence`.
+
+### 3. `span` is not a proper geometry model yet
+
+Current `span` is a semicolon-delimited list of modern countries.
+
+That is useful for filtering, but insufficient for historical geography.
+
+A large entity such as the Roman Empire or Ottoman Empire occupies different modern-country lanes over different time intervals.
+
+A proposed `BoxSegments` table should normalize this.
+
+### 4. Population is not filled
+
+The `Population` table is a scaffold only.
+
+The next population work should prioritize historically significant entities and major breakpoints rather than attempting annual estimates.
+
+### 5. Historical succession is modeled only for a small subset
+
+A `Links` table now exists (`docs/DATA_MODEL.md` §5: source box, target box, transition year, relationship type, confidence, source URL, notes), but it covers only 7 hand-authored rows in the Mediterranean/Europe cluster — the China cluster and the rest of the dataset still have no succession data. Most of the tables still know **what existed and when**, but not **what became what**.
+
+### 6. Architectural item dates may differ from the poster
+
+Some SEAIs did not have explicit years printed on the poster.
+
+Representative historical years were supplied for plotting and documented in notes.
+
+These should be reviewed before treating them as authoritative.
+
+## Recommended next data work
+
+Priority order:
+
+1. ~~Add `Links`.~~ Done for a small Mediterranean/Europe subset — see Milestone 4 (Phase 3 alluvial prototype) above. The China cluster from `docs/IMPLEMENTATION_PLAN.md` Phase 3 and the rest of the dataset remain unlinked.
+2. Add `BoxSegments`.
+3. Populate a small, representative subset of `Population`.
+4. Add real Wikipedia URLs gradually.
+5. ~~Build first interactive prototype.~~ Done — see Milestone 2 above.
+6. Let visualization needs drive further data refinement.
+
+## Recommended first population subset
+
+Do not fill everything at once.
+
+Start with:
+
+- Roman Empire;
+- Byzantine Empire;
+- Western Roman Empire;
+- Persian Empire;
+- Ottoman Empire;
+- major Chinese dynasties;
+- Maurya / Gupta / Mughal;
+- major Egyptian periods;
+- Frankish / French sequence;
+- Holy Roman Empire / German sequence.
+
+This is enough to test equal-width vs. population vs. logarithmic-width rendering.
+
+## Source discipline
+
+Treat the source poster as authoritative for box labels, poster colors, visual alignment, poster dates, and which SEAIs appear.
+
+External research should be clearly distinguished when used for population, exact historical dates, territorial interpretation, succession links, Wikipedia URLs, or expansion beyond the original poster.
diff --git a/projects/world-history/docs/VISUALIZATION.md b/projects/world-history/docs/VISUALIZATION.md
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+# Visualization Concepts
+
+## Overall direction
+
+The project should not simply redraw the original poster.
+
+The poster is the source dataset and visual inspiration. The site should expose relationships that are hard to see on paper.
+
+The strongest direction is a synchronized set of views built from one shared data model.
+
+# View 1: Timeline
+
+## Goal
+
+Provide a recognizable, interactive descendant of the source poster.
+
+Possible orientation:
+
+- time horizontally for stronger compatibility with Sankey/alluvial views;
+- region / modern-country lanes vertically.
+
+The original poster's vertical-time orientation can still be tested.
+
+## Box width modes
+
+Allow:
+
+- equal width;
+- population;
+- `log10(population)`;
+- `sqrt(population)`.
+
+Raw population may make smaller ancient polities disappear visually. `log10` or square root may be better compromises.
+
+## Interaction
+
+Clicking a box should:
+
+- select it persistently;
+- highlight corresponding SEAIs;
+- update the inspector;
+- highlight predecessor/successor links;
+- dim unrelated boxes.
+
+Hover can enhance but must not be the only interaction.
+
+# View 2: Alluvial / Sankey
+
+## Goal
+
+Show succession, fragmentation, unification, conquest, and institutional continuity.
+
+This is conceptually an **alluvial history view**, even if implemented with a Sankey library.
+
+Recommended explanatory text:
+
+> Ribbon width represents the estimated scale of the historical entity, not a literal transfer of people.
+
+Chronology should constrain horizontal placement.
+
+Do not allow generic auto-layout to place a 500 BCE node to the right of a 500 CE node.
+
+# View 3: Population river / streamgraph
+
+## Goal
+
+Show demographic scale through time.
+
+Potential hierarchy:
+
+```text
+World
+  → Region
+    → Civilization / polity
+```
+
+This becomes especially useful once population estimates are filled.
+
+The browser or build script can interpolate between sparse knot points.
+
+Candidate interpolation:
+
+- linear population;
+- log-linear population.
+
+# View 4: Genealogy / relationship graph
+
+This emphasizes relationship type rather than width.
+
+Potential use:
+
+- inspect one polity’s predecessors;
+- inspect successors;
+- distinguish conquest from dynastic transition;
+- explore cross-regional relationships.
+
+This can wait until `Links` matures.
+
+# Proposed first page
+
+```text
+┌─────────────────────────────────────────────────────────────┐
+│ WORLD HISTORY EXPLORER                                     │
+│ Date range     Region       Width basis       SEAIs         │
+├─────────────────────────────────────────────────────────────┤
+│                                                             │
+│                 ALLUVIAL / SANKEY                           │
+│                                                             │
+├──────────────────────────────────────┬──────────────────────┤
+│ Timeline                             │ Inspector             │
+│                                      │                       │
+│                                      │ Selected box          │
+│                                      │ Dates                 │
+│                                      │ Population            │
+│                                      │ SEAIs                 │
+│                                      │ Wikipedia             │
+└──────────────────────────────────────┴──────────────────────┘
+```
+
+On narrow screens, stack vertically.
+
+# Technology comparison
+
+## Plotly
+
+Best for rapid prototype and initial Sankey.
+
+Advantages:
+
+- fast;
+- mature;
+- good tooltips;
+- easy static output.
+
+Limitations:
+
+- custom timeline/Sankey hybrid geometry may become awkward;
+- exact node placement can be restrictive;
+- advanced cross-view interaction may feel like fighting the library.
+
+Recommendation: **use Plotly for the first functional experiment.**
+
+## Apache ECharts
+
+Good for a polished interactive dashboard with strong built-in interaction.
+
+Recommendation: consider it if Plotly works conceptually but feels too scientific or generic.
+
+## D3
+
+Best for the likely final bespoke visualization.
+
+Advantages:
+
+- maximum control;
+- direct SVG geometry;
+- exact chronology;
+- variable-width ribbons;
+- synchronized custom views.
+
+Cost:
+
+- more code;
+- more layout responsibility.
+
+Recommendation: **likely final renderer if the project becomes a custom temporal Sankey.**
+
+# Temporal Sankey concept
+
+Instead of constant-width links, let ribbon width vary with time.
+
+This produces a hybrid of:
+
+- Sankey;
+- alluvial;
+- streamgraph;
+- timeline.
+
+That is a strong reason to keep population as a time series.
+
+# Filtering
+
+Recommended controls:
+
+### Geography
+
+- all;
+- region;
+- modern country.
+
+### Time
+
+- brush/slider;
+- optional typed year range.
+
+### Width
+
+- equal;
+- population;
+- log population;
+- square root population.
+
+### Layers
+
+- SEAIs;
+- population uncertainty;
+- modern-country lanes;
+- succession links;
+- selected ancestry/descendency only.
+
+# Inspector behavior
+
+Selecting a Box should show:
+
+- name;
+- dates;
+- region/span;
+- source color;
+- population at selected date;
+- low/high estimate;
+- population method;
+- confidence;
+- SEAIs;
+- notes;
+- Wikipedia link.
+
+Selecting a SEAI should show name, year, parent box, icon type, notes, and Wikipedia link.
+
+# Visual uncertainty
+
+Possible future encodings:
+
+- dotted outline for uncertain boundaries;
+- translucent population bands for low/high;
+- warning glyph for low-confidence transcription;
+- approximate-date prefix preserved in labels.
+
+# Accessibility
+
+- selection should not depend on hover;
+- interactive marks should be keyboard reachable where practical;
+- inspector should mirror tooltip information;
+- color should not be the sole encoding.
+
+# First prototype success criteria
+
+The first prototype is successful if it can:
+
+1. load generated static JSON;
+2. render a chronological Sankey/alluvial subset;
+3. render a simple timeline;
+4. select a box in either view;
+5. update a shared inspector;
+6. filter by region;
+7. switch width basis between equal and placeholder population mode;
+8. deploy with no server-side component.
diff --git a/projects/world-history/docs/timescaleRequirement.md b/projects/world-history/docs/timescaleRequirement.md
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+# Requirement: Semantic Zoom Time Scaling
+## Purpose
+The timeline must support a nonlinear **semantic zoom** time scale so that very long historical spans allocate more horizontal space to recent history, while shorter visible spans progressively approach ordinary linear time.
+The goal is to reduce crowding of recent events in multi-millennial views without making close-up historical views feel geometrically distorted.
+## Core Mapping
+Let:
+- `t` = historical year
+- `tMax` = most recent year visible in the current viewport
+- `tMin` = earliest year visible in the current viewport
+- `M = tMax - tMin` = visible time span in years
+- `a = tMax - t` = age of an event relative to the right edge of the viewport
+- `s` = user-adjustable scale parameter in the range `[-2, +2]`
+Define the semantic zoom exponent as:
+```text
+p = 1 / (1 + (M / 3000) * 2^s)
+
+Map time into normalized horizontal screen position with:
+
+x = 1 - (a / M)^p
+
+where:
+
+0 <= x <= 1
+
+Interpretation:
+
+* x = 0 corresponds to tMin
+* x = 1 corresponds to tMax
+
+Default Behavior
+
+The default slider value shall be:
+
+s = 0
+
+At the default setting:
+
+p = 1 / (1 + M/3000)
+
+This gives approximately:
+
+Visible span	Exponent p	Behavior
+50 years	0.984	essentially linear
+100 years	0.968	essentially linear
+300 years	0.909	mildly nonlinear
+1,000 years	0.750	moderate recent-history expansion
+3,000 years	0.500	square-root scaling
+6,000 years	0.333	strong recent-history expansion
+
+Thus, a 3,000-year visible span naturally uses approximately square-root scaling, while short historical windows relax smoothly toward linear time.
+
+User Control
+
+Provide an interactive slider:
+
+range: -2 to +2
+default: 0
+
+The slider modifies the amount of nonlinear compression through the 2^s term.
+
+Expected interpretation:
+
+* negative values → more linear / less recent-history emphasis
+* zero → recommended default semantic scaling
+* positive values → stronger expansion of recent history
+
+Suggested UI label:
+
+Time compression
+Ancient detail  ←  0  →  Recent detail
+
+Alternative labels are acceptable if they communicate the same effect clearly.
+
+Do not expose the raw mathematical parameter unless useful in an advanced/debug mode.
+
+Important Constraint
+
+Do not use this earlier additive formulation:
+
+p = 1 / (1 + M/3000 + s)
+
+because the denominator can reach zero or become negative for valid slider values.
+
+Use the multiplicative form:
+
+p = 1 / (1 + (M/3000) * 2^s)
+
+which remains finite and positive across the required slider range.
+
+Zoom Interaction
+
+The semantic scaling must update dynamically whenever the visible time range changes.
+
+For example:
+
+3000 BCE–2026
+
+should be strongly nonlinear, while zooming into:
+
+1800–2026
+
+should automatically become close to linear.
+
+The transition should be continuous.
+
+If technically practical, animate the layout smoothly while zooming so that historical objects visibly relax toward linear spacing as the viewport narrows.
+
+Avoid abrupt remapping after zoom completion.
+
+Coordinate Stability
+
+The mapping must depend only on:
+
+* current visible time span;
+* current slider value.
+
+It must not depend on:
+
+* number of visible SEAIs;
+* event density;
+* filtering choices;
+* population;
+* number of boxes shown.
+
+This is intentional.
+
+A historical date should remain at the same screen position for a given:
+
+[tMin, tMax, s]
+
+regardless of which event layers are enabled.
+
+Shared Scale
+
+All time-based visual elements in a view must use the same semantic transform, including:
+
+* historical box start/end coordinates;
+* SEAIs;
+* architecture/event markers;
+* succession transitions;
+* Sankey/alluvial node placement where chronology determines x-position;
+* population knot points;
+* time grid/tick locations.
+
+Do not mix linear placement for some elements with semantic placement for others within the same timeline view.
+
+Axis Labels and Interpretation
+
+Because the timeline is nonlinear, pixel distance must not be presented as proportional elapsed time.
+
+The UI must preserve clear historical-date labeling.
+
+Recommended approaches:
+
+* transform year ticks using the same scale;
+* provide sufficiently frequent labeled year ticks;
+* optionally show a small linear overview ruler;
+* retain BCE/CE labels clearly;
+* show exact year/date in hover/selection inspectors.
+
+The interface should make it difficult for a reader to mistake equal screen distance for equal elapsed time.
+
+Tick Generation
+
+Generate tick years in calendar time first, then transform their positions.
+
+Do not generate evenly spaced screen ticks and infer calendar years afterward.
+
+Tick density may adapt to zoom level.
+
+Example candidate intervals:
+
+5000-year view: 500- or 1000-year ticks
+2000-year view: 250- or 500-year ticks
+500-year view: 50- or 100-year ticks
+100-year view: 10- or 20-year ticks
+
+Exact tick-selection logic may be tuned for readability.
+
+Implementation Guidance
+
+Implement the scale as a reusable function/module.
+
+Suggested API shape:
+
+semanticTimeScale({
+  tMin,
+  tMax,
+  scaler
+})
+
+which returns functions equivalent to:
+
+yearToX(year)
+xToYear(x)
+exponent()
+
+An inverse transform should be implemented so that pointer interactions can convert screen position back into historical time.
+
+Given:
+
+x = 1 - (a/M)^p
+
+the inverse is:
+
+a = M * (1 - x)^(1/p)
+t = tMax - a
+
+Validation
+
+At minimum, test the following:
+
+Boundary conditions
+
+yearToX(tMin) == 0
+yearToX(tMax) == 1
+
+Monotonicity
+
+For:
+
+t1 < t2
+
+require:
+
+yearToX(t1) < yearToX(t2)
+
+for all valid:
+
+M > 0
+s in [-2, +2]
+
+Round trip
+
+For representative years:
+
+xToYear(yearToX(t)) ≈ t
+
+within floating-point tolerance.
+
+Zoom behavior
+
+Confirm that, at s = 0:
+
+M = 3000 → p = 0.5
+
+and that:
+
+M → 0 → p → 1
+
+so close-up views become linear.
+
+Slider behavior
+
+Confirm that:
+
+s decreases → p increases → mapping becomes more linear
+s increases → p decreases → recent history receives more screen space
+
+Performance
+
+Changing either:
+
+* zoom extent;
+* slider value
+
+should update the visualization interactively without reloading the page.
+
+For SVG/D3 rendering, updating only x-related geometry is preferred where possible.
+
+The transform should be inexpensive enough to recompute continuously during slider movement.
+
+Design Intent
+
+This semantic scale is preferred over event-density scaling for the primary timeline because it gives stable geometry.
+
+Event-density scaling may still be explored later as an optional visualization mode, but it must not be the default timeline coordinate system.
+
+The default timeline should prioritize:
+
+1. chronological stability;
+2. smooth semantic zoom;
+3. readability of recent history;
+4. predictable interaction;
+5. simple user control.
+
diff --git a/projects/world-history/index.html b/projects/world-history/index.html
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+++ b/projects/world-history/index.html
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+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>World History Explorer</title>
+<meta name="description" content="An interactive, static visualization of world history, built from the ChartOrigin Timeline of World History poster.">
+<link rel="stylesheet" href="css/history.css">
+<script src="https://cdn.plot.ly/plotly-2.35.2.min.js"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/7.9.0/d3.min.js"></script>
+</head>
+<body>
+  <header>
+    <h1>World History Explorer</h1>
+    <p class="status" id="status">Loading data&hellip;</p>
+    <p class="summary" id="summary"></p>
+  </header>
+
+  <div class="controls">
+    <label for="region-filter">Region</label>
+    <select id="region-filter" aria-describedby="summary"></select>
+  </div>
+
+  <section aria-labelledby="timeline-heading" class="timeline-section">
+    <h2 id="timeline-heading">Timeline (prototype)</h2>
+    <p class="timeline-note">
+      One row per box in view, ordered chronologically; bar width shows the
+      poster's own start/end dates, not yet population-weighted &mdash; see
+      <code>docs/VISUALIZATION.md</code>. Six boxes have no legible start
+      date on the source poster (<code>ISSUES.md</code> ISSUE-005); their
+      bar runs to the left edge of the visible range with a dashed edge to
+      mark that as approximate, not a real date. Diamond markers are SEAIs.
+      Click a bar, or a box in the list below, to select it &mdash; the box
+      list already gives full keyboard access to every box shown here, so
+      this chart doesn't duplicate it with a hidden list of its own the way
+      the alluvial diagram below does. Selecting a box or a succession link
+      anywhere on the page (here, the list, or the alluvial diagram) is
+      reflected everywhere else: the selected box's bar and the alluvial
+      diagram's matching node both get an outline, and a selected link's two
+      endpoint boxes are outlined here too. The year range and time
+      compression slider below are shared with the alluvial diagram too
+      (see <code>docs/timescaleRequirement.md</code>): both views place
+      dates along the same nonlinear axis, so a year always lands at the
+      same relative position in both.
+    </p>
+    <div class="timeline-controls">
+      <label for="year-start">From year</label>
+      <input type="number" id="year-start" step="1">
+      <label for="year-end">To year</label>
+      <input type="number" id="year-end" step="1">
+      <label><input type="checkbox" id="show-seais"> Show SEAIs</label>
+      <label for="time-scale">Time compression (ancient detail &harr; recent detail)</label>
+      <input type="range" id="time-scale" min="-2" max="2" step="0.1" value="0">
+    </div>
+    <div
+      id="timeline"
+      role="img"
+      aria-label="Timeline of boxes in the current filter, ordered chronologically, with SEAI markers"
+    ></div>
+  </section>
+
+  <section aria-labelledby="alluvial-heading" class="alluvial-section">
+    <h2 id="alluvial-heading">Succession (alluvial view, prototype subset)</h2>
+    <p class="alluvial-note">
+      Ribbon width represents equal weighting for now, not literal population
+      transfer or estimated historical scale &mdash; see
+      <code>docs/VISUALIZATION.md</code>. Covers 7 hand-authored links, not
+      the full dataset: Roman Empire &rarr; Western Roman Empire and
+      &rarr; Byzantine Empire; Frankish Kingdom &rarr; West Francia and
+      &rarr; East Francia; West Francia &rarr; Kingdom of France; East
+      Francia &rarr; Holy Roman Empire; and Byzantine Empire &rarr; Ottoman
+      Empire. Selecting a node or link here is reflected in the timeline and
+      box list too, and vice versa &mdash; see the timeline's own note above.
+      Node position (left-to-right) is chronological, placed on the same
+      shared, nonlinear time scale as the timeline above &mdash; the year
+      range and time compression slider up there apply here too.
+    </p>
+    <div
+      id="alluvial"
+      role="img"
+      aria-label="Alluvial diagram of a small subset of historical successions"
+      aria-describedby="alluvial-list-heading"
+    ></div>
+    <h3 id="alluvial-list-heading" class="visually-hidden">
+      Successions in the alluvial diagram (text alternative, also usable by keyboard)
+    </h3>
+    <ul id="alluvial-list" class="visually-hidden"></ul>
+  </section>
+
+  <main class="panels">
+    <section aria-labelledby="list-heading">
+      <h2 id="list-heading" class="visually-hidden-heading">Boxes</h2>
+      <ul id="box-list"></ul>
+    </section>
+
+    <section id="inspector" aria-labelledby="inspector-heading">
+      <h2 id="inspector-heading" class="visually-hidden-heading">Inspector</h2>
+      <div id="inspector-content">
+        <p>Select a box to see details.</p>
+      </div>
+    </section>
+  </main>
+
+  <footer>
+    <p>
+      This is a Phase 2/3/4/5/5.5 slice (click a box, inspect it, filter by
+      region and year range; a small alluvial/Sankey succession prototype; a
+      first D3 timeline view; selection synchronized across all of the
+      above; a shared, nonlinear semantic-zoom time scale across both the
+      timeline and the alluvial diagram) &mdash; population-based box width,
+      BoxSegments-based geography, and full-dataset succession links are
+      still to come. See
+      <code>docs/IMPLEMENTATION_PLAN.md</code> for the build plan and
+      <code>docs/STATUS.md</code> for current data coverage.
+    </p>
+  </footer>
+
+  <script type="module" src="js/app.js"></script>
+</body>
+</html>
diff --git a/projects/world-history/js/README.md b/projects/world-history/js/README.md
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--- /dev/null
+++ b/projects/world-history/js/README.md
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+# js/
+
+Plain modular JavaScript for the static site. No framework, no bundler, no
+build step — loaded directly as ES modules from `index.html`.
+
+Current modules (Phase 2–5.5):
+
+- `data.js` — fetches `data/*.json` (including `links.json`) and builds
+  lookup indices. Knows nothing about rendering or state.
+- `state.js` — `createStore()`, a minimal pub-sub state container. Knows
+  nothing about data loading or rendering.
+- `timescale.js` — Phase 5.5 semantic-zoom time scale
+  (`docs/timescaleRequirement.md`). `semanticTimeScale({tMin, tMax, scaler})`
+  returns pure `yearToX`/`xToYear`/`exponent` functions for the nonlinear
+  mapping `x = 1 - (a/M)^p` — no D3/DOM/Plotly dependency, so it's the one
+  scale every time-based element on the page (timeline bars/SEAIs/ticks,
+  Sankey node x-position) is required to share rather than each computing
+  its own linear normalization. `timeTicks(tMin, tMax)` picks candidate tick
+  years in calendar time first, for the caller to run through that same
+  scale. Has a committed test, `timescale.test.mjs` — run with `node
+  js/timescale.test.mjs`.
+- `sankey.js` — Phase 3 alluvial prototype. `buildSankeyFigure()` is a pure
+  data transform from `Links`/`Boxes` to a Plotly Sankey figure (nodes
+  ordered chronologically, `arrangement: "fixed"`); `renderSankey()` calls
+  `Plotly.newPlot`, wires `plotly_click` to node/link selection callbacks,
+  and resolves to `{ boxIds }`. Loaded from `cdn.plot.ly` in `index.html`,
+  not bundled. `applySankeySelection()` (Phase 5) re-colors the
+  already-rendered trace via `Plotly.restyle` to reflect a selection made
+  anywhere on the page, without re-running `Plotly.newPlot` (which would
+  double-register the click handler); the actual selection→style
+  computation is split out into `computeSankeyHighlight()`, a pure function
+  with no Plotly/DOM dependency. Node x-position (Phase 5.5) comes from
+  `computeSankeyNodeX()` — the shared `timescale.js` scale over the app's
+  `state.yearStart`/`yearEnd`/`timeScale`, not a per-subset min/max — and
+  `applySankeyTimeScale()` re-applies it via `Plotly.restyle` (kept separate
+  from `applySankeySelection()`, one extra restyle call rather than merging
+  position into the selection-highlight path) whenever that state changes.
+  `buildSankeyFigure()`, `computeSankeyHighlight()`, and
+  `computeSankeyNodeX()` all have a committed test, `sankey.test.mjs` — run
+  with `node js/sankey.test.mjs`.
+- `timeline.js` — Phase 4 timeline prototype. `buildTimelineLayout()` is a
+  pure data transform from `Boxes`/SEAIs plus the shared filter state
+  (region, year range, SEAI toggle, time-scale slider) to a row list, SEAI
+  marker list, and axis tick list, one row per box in view, ordered
+  chronologically, with every x-position computed via the shared
+  `timescale.js` scale (Phase 5.5); `renderTimeline()` draws it as an SVG
+  with D3 (bars + diamond SEAI markers + a hand-built BCE/CE year axis) and
+  wires bar clicks to box selection. Loaded from `cdnjs.cloudflare.com` in
+  `index.html`, not bundled. Box width is still literal start/end year, not
+  population-based (see `ISSUES.md` ISSUE-003). `buildTimelineLayout()` has
+  a committed test, `timeline.test.mjs` — run with `node
+  js/timeline.test.mjs` (the project root's `package.json` sets `"type":
+  "module"` so Node can load these files directly). `renderTimeline()` also
+  accepts `state.linkHighlightBoxIds` (Phase 5) to outline a selected link's
+  two endpoint boxes.
+- `app.js` — wiring: loads data, creates the store, renders the box
+  list/inspector/region-filter UI, the alluvial diagram, and the timeline
+  into `index.html`; handles click-to-select for boxes and links; wires the
+  year-range inputs and the Phase 5.5 time-scale slider (`input` event, so
+  it updates continuously while dragging) into the shared store; and
+  (Phase 5) keeps every panel's selection display in sync on every store
+  change — the box list's `.selected` class, the alluvial list's
+  `.selected`/`aria-pressed`, the timeline's outline (including link
+  endpoints), and the Sankey diagram's node/link outline via
+  `applySankeySelection()` plus (Phase 5.5) node position via
+  `applySankeyTimeScale()`.
+
+Planned (later phases, see `docs/IMPLEMENTATION_PLAN.md`): a larger `Links`
+subset covering the China cluster and beyond (see `ISSUES.md` ISSUE-004);
+population-based box/ribbon width (Phase 6, ISSUE-003).
diff --git a/projects/world-history/js/app.js b/projects/world-history/js/app.js
new file mode 100644
index 0000000..6251711
--- /dev/null
+++ b/projects/world-history/js/app.js
@@ -0,0 +1,408 @@
+// Wiring: load data, hold shared state, render. This is the "small subset"
+// slice from AGENTS.md's Scope control -- a sortable/filterable list of
+// Boxes with click-to-select and an inspector panel, a small alluvial/Sankey
+// succession prototype over data/links.json (Phase 3), a first D3
+// timeline view (Phase 4), and cross-panel selection sync between the two
+// plus the box list/alluvial list (Phase 5). Box width in the timeline is
+// not yet population-based (Population is still a scaffold -- see
+// ISSUE-003).
+
+import { loadAllData, regionGroups } from "./data.js";
+import { createStore } from "./state.js";
+import { renderSankey, applySankeySelection, applySankeyTimeScale } from "./sankey.js";
+import { buildTimelineLayout, renderTimeline } from "./timeline.js";
+
+const TODO_URL = "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals";
+
+const els = {
+  status: document.getElementById("status"),
+  summary: document.getElementById("summary"),
+  regionFilter: document.getElementById("region-filter"),
+  boxList: document.getElementById("box-list"),
+  inspector: document.getElementById("inspector-content"),
+  alluvial: document.getElementById("alluvial"),
+  alluvialList: document.getElementById("alluvial-list"),
+  timeline: document.getElementById("timeline"),
+  yearStart: document.getElementById("year-start"),
+  yearEnd: document.getElementById("year-end"),
+  showSeais: document.getElementById("show-seais"),
+  timeScale: document.getElementById("time-scale"),
+};
+
+function setStatus(message, isError = false) {
+  els.status.textContent = message;
+  els.status.classList.toggle("status-error", isError);
+}
+
+function renderSummary(data) {
+  els.summary.textContent =
+    `${data.boxes.length} boxes • ${data.seais.length} SEAIs • ` +
+    `${data.population.length} population rows • ${data.regions.length} region-country rows`;
+}
+
+function populateRegionFilter(boxes) {
+  const groups = regionGroups(boxes);
+  els.regionFilter.innerHTML = "";
+  const allOption = document.createElement("option");
+  allOption.value = "all";
+  allOption.textContent = "All regions";
+  els.regionFilter.appendChild(allOption);
+  for (const group of groups) {
+    const option = document.createElement("option");
+    option.value = group;
+    option.textContent = group;
+    els.regionFilter.appendChild(option);
+  }
+}
+
+// A handful of boxes (ISSUE-005: illegible "c. [BCE]" prehistory labels on
+// the source poster) have a null start_year but a real end_year. Falling
+// back to end_year for the sort key would misfile them next to boxes whose
+// *start* date matches that number -- e.g. an Indigenous Era box ending in
+// 1607 would sort next to 16th-century boxes instead of near other
+// prehistoric-start entities. Sort those to the front instead.
+function filteredBoxes(data, state) {
+  return data.boxes
+    .filter((b) => state.regionFilter === "all" || b.region_group === state.regionFilter)
+    .slice()
+    .sort((a, b) => {
+      const ay = a.start_year ?? Number.NEGATIVE_INFINITY;
+      const by = b.start_year ?? Number.NEGATIVE_INFINITY;
+      return ay - by;
+    });
+}
+
+function renderList(data, state) {
+  const boxes = filteredBoxes(data, state);
+  els.boxList.innerHTML = "";
+
+  if (boxes.length === 0) {
+    const empty = document.createElement("li");
+    empty.className = "box-empty";
+    empty.textContent = "No boxes match this filter.";
+    els.boxList.appendChild(empty);
+    return;
+  }
+
+  for (const box of boxes) {
+    const li = document.createElement("li");
+    const button = document.createElement("button");
+    button.type = "button";
+    button.className = "box-item";
+    button.setAttribute("aria-pressed", String(box.box_id === state.selectedBoxId));
+    if (box.box_id === state.selectedBoxId) button.classList.add("selected");
+
+    const swatch = document.createElement("span");
+    swatch.className = "swatch";
+    swatch.style.backgroundColor = box.color_hex || "transparent";
+    swatch.setAttribute("aria-hidden", "true");
+
+    const label = document.createElement("span");
+    label.className = "box-label";
+    label.textContent = `${box.box_name} (${box.start_label ?? "?"}–${box.end_label ?? "?"})`;
+
+    button.append(swatch, label);
+    button.addEventListener("click", () => {
+      store.set({
+        selectedBoxId: box.box_id === store.get().selectedBoxId ? null : box.box_id,
+        selectedLinkId: null,
+      });
+    });
+
+    li.appendChild(button);
+    els.boxList.appendChild(li);
+  }
+}
+
+// Text/keyboard alternative to the Plotly Sankey diagram (visually hidden
+// by default, see css/history.css .visually-hidden's :focus-within
+// exception). Plotly's own SVG hit-targets are mouse-driven with no
+// tabindex, so this is the only way a keyboard/screen-reader user can
+// browse or select a link at all -- it's populated from data/links.json
+// directly, independent of whether Plotly itself loaded (see the
+// try/catch around renderSankey below).
+function renderAlluvialList(data) {
+  if (!els.alluvialList) return;
+  els.alluvialList.innerHTML = "";
+  for (const link of data.links) {
+    const source = data.boxesById.get(link.source_box_id);
+    const target = data.boxesById.get(link.target_box_id);
+    const li = document.createElement("li");
+    const button = document.createElement("button");
+    button.type = "button";
+    button.dataset.linkId = link.link_id;
+    button.setAttribute("aria-pressed", "false");
+    button.textContent =
+      `${source?.box_name ?? link.source_box_id} → ${target?.box_name ?? link.target_box_id} ` +
+      `(${link.year ?? "?"}, ${link.relation_type ?? "?"})`;
+    button.addEventListener("click", () => {
+      store.set({ selectedLinkId: link.link_id, selectedBoxId: null });
+    });
+    li.appendChild(button);
+    els.alluvialList.appendChild(li);
+  }
+}
+
+// Phase 5: the buttons above are built once (the link list itself never
+// changes), so selection is synced separately here on every state change,
+// the same "build once, toggle a class on change" split renderList() uses
+// for the box list's own .selected state.
+function renderAlluvialListSelection(state) {
+  if (!els.alluvialList) return;
+  for (const button of els.alluvialList.querySelectorAll("button")) {
+    const isSelected = button.dataset.linkId === state.selectedLinkId;
+    button.setAttribute("aria-pressed", String(isSelected));
+    button.classList.toggle("selected", isSelected);
+  }
+}
+
+// Re-derives the layout and re-draws the whole SVG on every state change
+// (region/year filter, SEAI toggle, box selection) -- the dataset is small
+// enough (198 boxes) that a full redraw is simpler than diffing, matching
+// renderList()'s same full-redraw approach above.
+//
+// Phase 5: a selected link (data.linksById, not part of the shared store
+// itself -- the store only knows the id) is resolved here to its two
+// endpoint box_ids and passed through as state.linkHighlightBoxIds, so
+// selecting a link anywhere still shows something on the timeline even
+// though the timeline has no link geometry of its own to select. Deriving
+// this here (not in timeline.js) keeps timeline.js ignorant of Links, the
+// same separation buildTimelineLayout already has from data.js's indices.
+function renderTimelineView(data, state) {
+  if (!els.timeline) return;
+  try {
+    const layout = buildTimelineLayout(data.boxes, data.seaisByBoxId, state);
+    const link = state.selectedLinkId ? data.linksById.get(state.selectedLinkId) : null;
+    const linkHighlightBoxIds = link ? new Set([link.source_box_id, link.target_box_id]) : null;
+    renderTimeline(
+      els.timeline,
+      layout,
+      { ...state, linkHighlightBoxIds },
+      { onSelectBox: (boxId) => store.set({ selectedBoxId: boxId, selectedLinkId: null }) }
+    );
+  } catch (err) {
+    // D3 failing to load (e.g. offline, CDN blocked) shouldn't take down
+    // the rest of the page -- same reasoning as the try/catch around
+    // renderSankey in main() below.
+    els.timeline.textContent = `Timeline unavailable: ${err.message}`;
+  }
+}
+
+// Phase 5: `sankeyInfo` is only set once renderSankey() has actually
+// resolved (see main() below) -- until then this is a no-op, since
+// Plotly.restyle needs the trace to already exist. A restyle failure is
+// swallowed rather than surfaced through els.alluvial.textContent like
+// renderSankey's own try/catch does: losing the selection *highlight* isn't
+// the same failure as losing the diagram itself, and clobbering an already-
+// rendered chart with an error message over a cosmetic sync issue would be
+// worse than just leaving the highlight stale.
+let sankeyInfo = null;
+function renderSankeySelection(data, state) {
+  if (!sankeyInfo || !els.alluvial) return;
+  try {
+    applySankeySelection(els.alluvial, { links: data.links, boxIds: sankeyInfo.boxIds }, state);
+  } catch (err) {
+    console.warn("Sankey selection sync failed:", err);
+  }
+}
+
+// Phase 5.5: kept as its own function/subscribe entry, separate from
+// renderSankeySelection above, rather than merged into it -- position
+// (this) and selection-highlight (that) are different concerns, and
+// keeping them apart avoids touching the already-reviewed Milestone 6
+// selection code for this milestone (see js/sankey.js's
+// applySankeyTimeScale comment for the fuller reasoning).
+function renderSankeyTimeScale(data, state) {
+  if (!sankeyInfo || !els.alluvial) return;
+  try {
+    applySankeyTimeScale(els.alluvial, { boxIds: sankeyInfo.boxIds, boxesById: data.boxesById }, state);
+  } catch (err) {
+    console.warn("Sankey time-scale sync failed:", err);
+  }
+}
+
+function renderInspector(data, state) {
+  if (state.selectedLinkId) {
+    renderLinkInspector(data, state.selectedLinkId);
+    return;
+  }
+
+  const boxId = state.selectedBoxId;
+  if (!boxId) {
+    els.inspector.innerHTML = "<p>Select a box, or a node/link in the alluvial diagram, to see details.</p>";
+    return;
+  }
+
+  const box = data.boxesById.get(boxId);
+  if (!box) {
+    els.inspector.innerHTML = "<p>Selected box not found.</p>";
+    return;
+  }
+
+  const seais = data.seaisByBoxId.get(boxId) || [];
+  const urlLine =
+    box.url && box.url !== TODO_URL
+      ? `<p><a href="${escapeAttr(box.url)}">Wikipedia</a></p>`
+      : "<p>Wikipedia: not yet added (placeholder).</p>";
+
+  const seaiList = seais.length
+    ? `<ul>${seais.map((s) => `<li>${escapeHtml(s.name)} (${escapeHtml(String(s.year_label ?? s.year ?? "?"))})</li>`).join("")}</ul>`
+    : "<p>None recorded.</p>";
+
+  els.inspector.innerHTML = `
+    <h2>${escapeHtml(box.box_name)}</h2>
+    <p>${escapeHtml(box.start_label ?? "?")}–${escapeHtml(box.end_label ?? "?")}</p>
+    <p>Region: ${escapeHtml(box.region_group ?? "?")} — Span: ${escapeHtml(box.span ?? "?")}</p>
+    <p>Confidence: ${escapeHtml(box.confidence ?? "?")}</p>
+    ${box.notes ? `<p>Notes: ${escapeHtml(box.notes)}</p>` : ""}
+    ${urlLine}
+    <h3>SEAIs (${seais.length})</h3>
+    ${seaiList}
+  `;
+}
+
+function renderLinkInspector(data, linkId) {
+  const link = data.linksById.get(linkId);
+  if (!link) {
+    els.inspector.innerHTML = "<p>Selected link not found.</p>";
+    return;
+  }
+
+  const source = data.boxesById.get(link.source_box_id);
+  const target = data.boxesById.get(link.target_box_id);
+  const urlLine = link.source_url
+    ? `<p><a href="${escapeAttr(link.source_url)}">Source</a></p>`
+    : "<p>No source recorded.</p>";
+
+  els.inspector.innerHTML = `
+    <h2>${escapeHtml(source?.box_name ?? link.source_box_id)} &rarr; ${escapeHtml(target?.box_name ?? link.target_box_id)}</h2>
+    <p>${escapeHtml(link.year != null ? String(link.year) : "?")} &mdash; ${escapeHtml(link.relation_type ?? "?")}</p>
+    <p>Confidence: ${escapeHtml(link.confidence ?? "?")}</p>
+    ${link.notes ? `<p>Notes: ${escapeHtml(link.notes)}</p>` : ""}
+    ${urlLine}
+  `;
+}
+
+function escapeHtml(str) {
+  return String(str).replace(/[&<>"']/g, (c) => ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" }[c]));
+}
+function escapeAttr(str) {
+  return escapeHtml(str);
+}
+
+let store;
+
+async function main() {
+  setStatus("Loading data…");
+  let data;
+  try {
+    data = await loadAllData("data/");
+  } catch (err) {
+    setStatus(`Failed to load data: ${err.message}`, true);
+    return;
+  }
+
+  setStatus("");
+  renderSummary(data);
+  populateRegionFilter(data.boxes);
+
+  store = createStore();
+  store.subscribe((state) => {
+    renderList(data, state);
+    renderInspector(data, state);
+    renderTimelineView(data, state);
+    renderAlluvialListSelection(state);
+    renderSankeySelection(data, state);
+    renderSankeyTimeScale(data, state);
+  });
+
+  els.regionFilter.addEventListener("change", () => {
+    store.set({ regionFilter: els.regionFilter.value, selectedBoxId: null, selectedLinkId: null });
+  });
+
+  // Year-range/SEAI controls only affect the timeline view; they intentionally
+  // leave selectedBoxId/selectedLinkId alone (unlike the region filter above,
+  // which clears selection because it can remove the selected box from the
+  // list entirely).
+  const initial = store.get();
+  els.yearStart.value = initial.yearStart;
+  els.yearEnd.value = initial.yearEnd;
+  els.showSeais.checked = initial.showSeais;
+  if (els.timeScale) els.timeScale.value = initial.timeScale;
+  // A reversed range (yearStart > yearEnd) doesn't crash js/timescale.js's
+  // semanticTimeScale (M just floors to a near-zero epsilon, per that
+  // module's own degenerate-domain guard), but it would draw chronology
+  // flowing right-to-left with no warning, which would violate AGENTS.md's
+  // "chronology must remain semantically correct" -- so reject it here
+  // instead of ever letting it reach the store. Revert the input's own
+  // displayed value too, or it would visually disagree with the state it
+  // failed to change.
+  els.yearStart.addEventListener("change", () => {
+    const value = Number(els.yearStart.value);
+    const current = store.get();
+    if (!Number.isFinite(value) || value > current.yearEnd) {
+      els.yearStart.value = current.yearStart;
+      return;
+    }
+    store.set({ yearStart: value });
+  });
+  els.yearEnd.addEventListener("change", () => {
+    const value = Number(els.yearEnd.value);
+    const current = store.get();
+    if (!Number.isFinite(value) || value < current.yearStart) {
+      els.yearEnd.value = current.yearEnd;
+      return;
+    }
+    store.set({ yearEnd: value });
+  });
+  els.showSeais.addEventListener("change", () => {
+    store.set({ showSeais: els.showSeais.checked });
+  });
+  // Phase 5.5 (docs/timescaleRequirement.md "Zoom Interaction"): recompute
+  // continuously while dragging, so this listens on `input` (fires on every
+  // drag tick) rather than `change` (fires only on release) like the
+  // controls above.
+  if (els.timeScale) {
+    els.timeScale.addEventListener("input", () => {
+      store.set({ timeScale: Number(els.timeScale.value) });
+    });
+  }
+
+  // Populated from the fetched data directly, independent of whether Plotly
+  // itself loads -- this is the accessible fallback, not just a mirror of
+  // the chart.
+  renderAlluvialList(data);
+
+  try {
+    sankeyInfo = await renderSankey(
+      els.alluvial,
+      { links: data.links, boxesById: data.boxesById },
+      store.get(),
+      {
+        onSelectBox: (boxId) => store.set({ selectedBoxId: boxId, selectedLinkId: null }),
+        onSelectLink: (link) => store.set({ selectedLinkId: link.link_id, selectedBoxId: null }),
+      }
+    );
+    // The diagram just rendered with no selection styling applied; if a
+    // selection was already made elsewhere while Plotly was still loading
+    // (a race the try/catch structure allows, since data-load/render is
+    // async), catch it up immediately rather than leaving it unhighlighted
+    // until the next unrelated state change. Same reasoning applies to the
+    // time scale (Phase 5.5) -- the slider could have moved during load too.
+    renderSankeySelection(data, store.get());
+    renderSankeyTimeScale(data, store.get());
+  } catch (err) {
+    // Plotly failing to load (e.g. offline, CDN blocked) shouldn't take
+    // down the rest of the page -- the box list/inspector/filter above
+    // still work without it.
+    els.alluvial.textContent = `Alluvial diagram unavailable: ${err.message}`;
+  }
+}
+
+main().catch((err) => {
+  // Belt-and-suspenders: the data-load try/catch inside main() already
+  // handles fetch failures, but a thrown error from rendering itself
+  // (e.g. an unexpected data shape) would otherwise surface only as an
+  // unhandled-rejection console warning with no user-visible message.
+  setStatus(`Unexpected error: ${err.message}`, true);
+});
diff --git a/projects/world-history/js/data.js b/projects/world-history/js/data.js
new file mode 100644
index 0000000..6d306ce
--- /dev/null
+++ b/projects/world-history/js/data.js
@@ -0,0 +1,93 @@
+// Data loading. Fetches the generated JSON in data/ and builds a few
+// convenience indices. This module knows nothing about rendering or state --
+// see docs/IMPLEMENTATION_PLAN.md Phase 2 ("separate data loading, state
+// management, and rendering").
+
+// Boxes/SEAIs/population/regions are load-bearing for the whole page (box
+// list, inspector, region filter) -- a missing/broken file among these is a
+// real failure and should reject loadAllData(). links.json only feeds the
+// Phase 3 alluvial prototype (js/sankey.js), which already degrades
+// gracefully on its own (see js/app.js's try/catch around renderSankey), so
+// it's fetched separately below and defaults to [] on failure instead of
+// taking the whole page down with it.
+const FILES = {
+  boxes: "boxes.json",
+  seais: "seais.json",
+  population: "population.json",
+  regions: "regions.json",
+};
+const OPTIONAL_FILES = {
+  links: "links.json",
+};
+
+/**
+ * Load boxes/seais/population/regions (required) and links (optional) from
+ * `baseUrl` (default "data/") and return { boxes, seais, population,
+ * regions, links, boxesById, seaisByBoxId, populationByBoxId, linksById,
+ * linksByBoxId }.
+ */
+export async function loadAllData(baseUrl = "data/") {
+  const entries = Object.entries(FILES);
+  const responses = await Promise.all(
+    entries.map(([, filename]) => fetch(baseUrl + filename))
+  );
+
+  const tables = {};
+  for (let i = 0; i < entries.length; i++) {
+    const [key, filename] = entries[i];
+    const res = responses[i];
+    if (!res.ok) {
+      throw new Error(`failed to load ${baseUrl}${filename}: ${res.status} ${res.statusText}`);
+    }
+    tables[key] = await res.json();
+  }
+
+  tables.links = [];
+  try {
+    const res = await fetch(baseUrl + OPTIONAL_FILES.links);
+    if (res.ok) {
+      tables.links = await res.json();
+    } else {
+      console.warn(`optional ${baseUrl}${OPTIONAL_FILES.links} failed to load: ${res.status} ${res.statusText}`);
+    }
+  } catch (err) {
+    console.warn(`optional ${baseUrl}${OPTIONAL_FILES.links} failed to load: ${err.message}`);
+  }
+
+  return { ...tables, ...buildIndices(tables) };
+}
+
+function buildIndices({ boxes, seais, population, links }) {
+  const boxesById = new Map(boxes.map((b) => [b.box_id, b]));
+
+  const seaisByBoxId = new Map();
+  for (const s of seais) {
+    if (!seaisByBoxId.has(s.box_id)) seaisByBoxId.set(s.box_id, []);
+    seaisByBoxId.get(s.box_id).push(s);
+  }
+
+  const populationByBoxId = new Map();
+  for (const p of population) {
+    if (!populationByBoxId.has(p.box_id)) populationByBoxId.set(p.box_id, []);
+    populationByBoxId.get(p.box_id).push(p);
+  }
+
+  const linksById = new Map(links.map((l) => [l.link_id, l]));
+
+  // Every box_id that appears as either end of a link, so the alluvial view
+  // knows which boxes have link data at all (see js/sankey.js).
+  const linksByBoxId = new Map();
+  for (const l of links) {
+    for (const boxId of [l.source_box_id, l.target_box_id]) {
+      if (!linksByBoxId.has(boxId)) linksByBoxId.set(boxId, []);
+      linksByBoxId.get(boxId).push(l);
+    }
+  }
+
+  return { boxesById, seaisByBoxId, populationByBoxId, linksById, linksByBoxId };
+}
+
+/** Distinct `region_group` values from Boxes, sorted, for a filter control. */
+export function regionGroups(boxes) {
+  return [...new Set(boxes.map((b) => b.region_group).filter(Boolean))].sort();
+}
diff --git a/projects/world-history/js/sankey.js b/projects/world-history/js/sankey.js
new file mode 100644
index 0000000..20714e0
--- /dev/null
+++ b/projects/world-history/js/sankey.js
@@ -0,0 +1,226 @@
+// Alluvial / Sankey prototype (docs/IMPLEMENTATION_PLAN.md Phase 3). Builds a
+// Plotly Sankey diagram from the boxes referenced by data/links.json -- a
+// small hand-authored subset (the "Mediterranean / Europe" candidate list),
+// not the full 198-box dataset. See docs/DATA_MODEL.md #5: "Not every
+// chronological adjacency should automatically become a link."
+//
+// Split into a pure data transform (buildSankeyFigure -- no Plotly/DOM
+// dependency, Node-testable) and a rendering function (renderSankey --
+// needs a real browser and the Plotly UMD build loaded as window.Plotly).
+
+import { semanticTimeScale } from "./timescale.js";
+
+// Plotly's fixed arrangement wants x strictly inside (0, 1); clamp away from
+// the edges so the first/last node aren't drawn clipped.
+const clamp = (v) => Math.min(0.98, Math.max(0.02, v));
+
+/**
+ * Phase 5.5 (docs/timescaleRequirement.md "Shared Scale"): Sankey node
+ * x-position is one of the elements explicitly called out as needing the
+ * *same* scale instance as the timeline -- so this uses the app's shared
+ * view domain (`state.yearStart`/`state.yearEnd`/`state.timeScale`), not a
+ * per-subset min/max the way the pre-5.5 version of buildSankeyFigure did.
+ * The node *set* itself is still whatever links.json references, unfiltered
+ * by yearStart/yearEnd (unchanged from before Phase 5.5) -- only where each
+ * node's x lands changes.
+ *
+ * Split out from buildSankeyFigure (same reasoning as
+ * computeSankeyHighlight below) so applySankeyTimeScale can recompute just
+ * the x array on a slider `input` event without rebuilding the whole
+ * figure.
+ */
+export function computeSankeyNodeX(boxIds, boxesById, state) {
+  const scale = semanticTimeScale({ tMin: state.yearStart, tMax: state.yearEnd, scaler: state.timeScale ?? 0 });
+  return boxIds.map((id) => {
+    const box = boxesById.get(id);
+    const y = box && typeof box.start_year === "number" ? box.start_year : state.yearStart;
+    return clamp(scale.yearToX(y));
+  });
+}
+
+/**
+ * Build a Plotly Sankey `data`/`layout` pair plus the `boxIds` array used to
+ * map a clicked node index back to a box_id.
+ *
+ * Node x-positions come from computeSankeyNodeX -- the shared semantic-zoom
+ * scale (Phase 5.5) -- so the diagram reads left-to-right in chronological
+ * order regardless of link/node insertion order, using the same
+ * [yearStart, yearEnd, timeScale] the timeline view uses. This is
+ * `arrangement: "fixed"` deliberately: AGENTS.md's "Visualization semantics"
+ * says chronology must remain semantically correct and auto-layout must not
+ * reorder nodes in a historically misleading way.
+ */
+export function buildSankeyFigure(links, boxesById, state) {
+  const boxIds = [...new Set(links.flatMap((l) => [l.source_box_id, l.target_box_id]))];
+
+  const nodeIndex = new Map(boxIds.map((id, i) => [id, i]));
+  const nodeLabel = boxIds.map((id) => boxesById.get(id)?.box_name ?? id);
+  const nodeColor = boxIds.map((id) => boxesById.get(id)?.color_hex || "#888888");
+  const nodeX = computeSankeyNodeX(boxIds, boxesById, state);
+  // x is meaningful (chronology); y only needs to keep nodes from
+  // overlapping, so spread evenly in insertion order.
+  const nodeY = boxIds.map((_, i) => 0.05 + (0.9 * i) / Math.max(1, boxIds.length - 1));
+
+  const linkSource = links.map((l) => nodeIndex.get(l.source_box_id));
+  const linkTarget = links.map((l) => nodeIndex.get(l.target_box_id));
+  // No population estimates are filled in yet (ISSUE-003), so every link in
+  // data/links.json uses "weight_basis": "equal" -- ribbon width here is not
+  // yet "estimated historical scale" per docs/VISUALIZATION.md View 2, just
+  // a placeholder equal weight until Phase 6 fills in population knots.
+  const linkValue = links.map(() => 1);
+  const linkLabel = links.map((l) => `${l.relation_type} (${l.year})`);
+
+  return {
+    boxIds,
+    data: [
+      {
+        type: "sankey",
+        orientation: "h",
+        arrangement: "fixed",
+        node: {
+          pad: 24,
+          thickness: 18,
+          label: nodeLabel,
+          color: nodeColor,
+          x: nodeX,
+          y: nodeY,
+        },
+        link: {
+          source: linkSource,
+          target: linkTarget,
+          value: linkValue,
+          label: linkLabel,
+        },
+      },
+    ],
+    layout: {
+      font: { size: 12 },
+      margin: { l: 8, r: 8, t: 8, b: 8 },
+    },
+  };
+}
+
+/**
+ * Render the Sankey figure into `container` (a DOM element) using the
+ * Plotly UMD build already loaded as `window.Plotly` (see index.html).
+ * Clicking a node calls `onSelectBox(boxId)`; clicking a link calls
+ * `onSelectLink(link)` with the matching row from data/links.json.
+ *
+ * Resolves to `{ boxIds }` (the same array buildSankeyFigure computed,
+ * needed by applySankeySelection below to map a selected box_id back to a
+ * node index) once `Plotly.newPlot` resolves -- so an asynchronous Plotly
+ * failure -- not just a synchronous throw -- is still caught by
+ * js/app.js's try/catch around this call, instead of becoming an
+ * unhandled promise rejection that bypasses the intended fallback message.
+ */
+export async function renderSankey(container, { links, boxesById }, state, { onSelectBox, onSelectLink }) {
+  if (typeof window === "undefined" || !window.Plotly) {
+    throw new Error("Plotly is not loaded (expected window.Plotly on the page)");
+  }
+  const { data, layout, boxIds } = buildSankeyFigure(links, boxesById, state);
+
+  // Match the page's light/dark theme (css/history.css defines --bg/--fg on
+  // :root) instead of Plotly's opaque-white default, which would otherwise
+  // render as a stark white rectangle inside an otherwise dark-themed page.
+  const rootStyle = getComputedStyle(document.documentElement);
+  const bg = rootStyle.getPropertyValue("--bg").trim() || "#ffffff";
+  const fg = rootStyle.getPropertyValue("--fg").trim() || "#1a1a1a";
+  layout.paper_bgcolor = bg;
+  layout.plot_bgcolor = bg;
+  layout.font = { ...layout.font, color: fg };
+
+  await window.Plotly.newPlot(container, data, layout, { displayModeBar: false, responsive: true });
+
+  container.on("plotly_click", (event) => {
+    const point = event.points && event.points[0];
+    if (!point) return;
+    if (point.source && point.target) {
+      // Link trace click: Plotly gives {source, target} node objects, plus
+      // pointNumber indexing into the link arrays we supplied.
+      const link = links[point.pointNumber];
+      if (link) onSelectLink(link);
+    } else if (point.pointNumber !== undefined) {
+      // Node trace click: pointNumber indexes into node.label/x/y/color.
+      const boxId = boxIds[point.pointNumber];
+      if (boxId) onSelectBox(boxId);
+    }
+  });
+
+  return { boxIds };
+}
+
+/**
+ * Phase 5 (docs/IMPLEMENTATION_PLAN.md): pure computation of the
+ * `Plotly.restyle` arrays for `applySankeySelection` below -- split out
+ * (same reasoning as buildSankeyFigure/renderSankey and
+ * js/timeline.js's buildTimelineLayout/renderTimeline) so the actual
+ * selection→style logic is Node-testable without a browser/Plotly, even
+ * though applying it still needs both.
+ *
+ * Node fill stays the box's own color_hex (that's meaningful data, not a
+ * selection cue) -- selection instead adds a `node.line` outline, the same
+ * "don't just recolor" reasoning as .box-item.selected's checkmark and
+ * .timeline-bar.selected's stroke. Link color is set explicitly for every
+ * link (`muted` normally, `accent` for the selected one) since Plotly's own
+ * default link coloring isn't otherwise selection-aware.
+ *
+ * A selected *link* also outlines its two endpoint nodes (not just the
+ * link's own ribbon color) -- a Sankey trace has no non-color channel on
+ * the link itself (no line/pattern property, unlike node.line), so without
+ * this a selected link would be encoded by color alone, violating
+ * AGENTS.md's "color isn't the sole encoding" (council review finding).
+ */
+export function computeSankeyHighlight(links, boxIds, state, { accent, muted }) {
+  const selectedLink = state.selectedLinkId ? links.find((l) => l.link_id === state.selectedLinkId) : null;
+  const linkEndpointIds = selectedLink ? new Set([selectedLink.source_box_id, selectedLink.target_box_id]) : null;
+  return {
+    nodeLineWidth: boxIds.map((id) => (id === state.selectedBoxId || linkEndpointIds?.has(id) ? 3 : 0)),
+    nodeLineColor: boxIds.map(() => accent),
+    linkColor: links.map((l) => (l.link_id === state.selectedLinkId ? accent : muted)),
+  };
+}
+
+/**
+ * Re-color the already-rendered Sankey trace to reflect a selection made
+ * anywhere (box list, timeline, or the diagram itself) -- via
+ * `Plotly.restyle`, not a full `Plotly.newPlot` re-render, so the
+ * `plotly_click` handler bound once in renderSankey above never gets
+ * double-registered.
+ *
+ * Not awaited/queued: two rapid selections could in principle resolve their
+ * restyle promises out of order, transiently showing a stale highlight
+ * (council review finding). Self-corrects on the very next state change --
+ * the store re-renders full current state on every `set()`, so a stale
+ * frame can't persist -- not worth a request-cancellation mechanism for a
+ * cosmetic, self-healing gap.
+ */
+export function applySankeySelection(container, { links, boxIds }, state) {
+  if (typeof window === "undefined" || !window.Plotly) return;
+  const rootStyle = getComputedStyle(document.documentElement);
+  const accent = rootStyle.getPropertyValue("--accent").trim() || "#2456a8";
+  const muted = rootStyle.getPropertyValue("--muted").trim() || "#666666";
+
+  const { nodeLineWidth, nodeLineColor, linkColor } = computeSankeyHighlight(links, boxIds, state, { accent, muted });
+
+  window.Plotly.restyle(
+    container,
+    { "node.line.width": [nodeLineWidth], "node.line.color": [nodeLineColor], "link.color": [linkColor] },
+    [0]
+  );
+}
+
+/**
+ * Phase 5.5: re-position the already-rendered Sankey trace's nodes to
+ * reflect a change to the shared view domain/time-scale slider (`state`'s
+ * yearStart/yearEnd/timeScale) -- via `Plotly.restyle`, kept as its own
+ * function/call rather than folded into applySankeySelection above, per
+ * this milestone's design decision to keep position-syncing and
+ * selection-highlighting separate (minimizes churn on the already-reviewed
+ * Milestone 6 selection code; costs one extra `Plotly.restyle` call per
+ * state change, which is cheap relative to a full re-render).
+ */
+export function applySankeyTimeScale(container, { boxIds, boxesById }, state) {
+  if (typeof window === "undefined" || !window.Plotly) return;
+  const nodeX = computeSankeyNodeX(boxIds, boxesById, state);
+  window.Plotly.restyle(container, { "node.x": [nodeX] }, [0]);
+}
diff --git a/projects/world-history/js/sankey.test.mjs b/projects/world-history/js/sankey.test.mjs
new file mode 100644
index 0000000..e1921c0
--- /dev/null
+++ b/projects/world-history/js/sankey.test.mjs
@@ -0,0 +1,127 @@
+// Committed, repeatable test for sankey.js's two pure functions --
+// buildSankeyFigure (Phase 3) and computeSankeyHighlight (Phase 5). No
+// D3/Plotly/DOM dependency, see those functions' own comments.
+// Run with: node js/sankey.test.mjs
+//
+// Closes another instance of the same ISSUE-009 gap js/timeline.test.mjs
+// closed for timeline.js -- this is the first committed test for
+// sankey.js. renderSankey()/applySankeySelection() themselves still aren't
+// covered here -- that needs a real browser/DOM and Plotly, which this
+// environment doesn't have -- so this is a partial, not complete,
+// resolution of ISSUE-009 (see ISSUES.md).
+
+import { buildSankeyFigure, computeSankeyHighlight, computeSankeyNodeX } from "./sankey.js";
+import fs from "node:fs";
+import { fileURLToPath } from "node:url";
+
+const dataDir = fileURLToPath(new URL("../data/", import.meta.url));
+const boxes = JSON.parse(fs.readFileSync(dataDir + "boxes.json"));
+const links = JSON.parse(fs.readFileSync(dataDir + "links.json"));
+const boxesById = new Map(boxes.map((b) => [b.box_id, b]));
+
+let failures = 0;
+function assert(cond, msg) {
+  if (!cond) {
+    failures++;
+    console.error("FAIL:", msg);
+  } else {
+    console.log("ok:", msg);
+  }
+}
+
+// -- buildSankeyFigure (Phase 5.5: node x now comes from the shared,
+// app-wide semantic-zoom scale -- state, matching js/state.js's
+// initialState() defaults -- not a per-subset min/max) --
+const defaultState = { yearStart: -3000, yearEnd: 2026, timeScale: 0 };
+const figure = buildSankeyFigure(links, boxesById, defaultState);
+assert(figure.boxIds.length > 0, "buildSankeyFigure finds some boxIds from the links subset");
+assert(
+  new Set(figure.boxIds).size === figure.boxIds.length,
+  "boxIds has no duplicates (each box appears once regardless of how many links touch it)"
+);
+assert(figure.data[0].link.source.length === links.length, "one link entry per row in links.json");
+assert(figure.data[0].node.x.every((x) => x >= 0 && x <= 1), "every node x is normalized into [0,1]");
+// AGENTS.md "chronology must remain semantically correct": node x-order
+// should match start_year order among boxes that have one.
+const xByBox = figure.boxIds.map((id, i) => ({ id, x: figure.data[0].node.x[i], start: boxesById.get(id)?.start_year }));
+const dated = xByBox.filter((b) => typeof b.start === "number").sort((a, b) => a.start - b.start);
+for (let i = 1; i < dated.length; i++) {
+  assert(dated[i - 1].x <= dated[i].x, `node x-order matches start_year order (${dated[i - 1].id} before ${dated[i].id})`);
+}
+
+// -- computeSankeyNodeX: shares its result with what buildSankeyFigure put
+// into node.x above (same function, called with the same args) --
+{
+  const nodeX = computeSankeyNodeX(figure.boxIds, boxesById, defaultState);
+  assert(
+    nodeX.every((x, i) => x === figure.data[0].node.x[i]),
+    "computeSankeyNodeX matches buildSankeyFigure's node.x for the same state"
+  );
+  // Changing timeScale changes the exponent, so at least one node (a box not
+  // at yearStart or yearEnd exactly) should move.
+  const zoomedX = computeSankeyNodeX(figure.boxIds, boxesById, { ...defaultState, timeScale: 2 });
+  assert(zoomedX.some((x, i) => x !== nodeX[i]), "computeSankeyNodeX responds to a timeScale change");
+
+  // ISSUE-005: a box with no start_year (none of data/links.json's current
+  // subset has one, so this exercises the fallback with a synthetic box
+  // rather than real data) falls back to state.yearStart, same "don't
+  // fabricate a date" reasoning as js/timeline.js's approxStart -- not
+  // some other placeholder that could land it off-screen or at a
+  // misleadingly specific position (council review minor finding: this
+  // branch was previously untested).
+  const syntheticBoxesById = new Map(boxesById);
+  syntheticBoxesById.set("NO_START_YEAR", { box_id: "NO_START_YEAR", start_year: null });
+  const withUndated = computeSankeyNodeX([...figure.boxIds, "NO_START_YEAR"], syntheticBoxesById, defaultState);
+  assert(Number.isFinite(withUndated.at(-1)), "a box with no start_year still gets a finite node x");
+  assert(
+    Math.abs(withUndated.at(-1) - Math.min(0.98, Math.max(0.02, 0))) < 1e-9,
+    "a box with no start_year lands at the clamped left edge (state.yearStart)"
+  );
+}
+
+// -- computeSankeyHighlight --
+const colors = { accent: "#accent", muted: "#muted" };
+const none = computeSankeyHighlight(links, figure.boxIds, { selectedBoxId: null, selectedLinkId: null }, colors);
+assert(none.nodeLineWidth.every((w) => w === 0), "no selection -> every node line width is 0");
+assert(none.linkColor.every((c) => c === colors.muted), "no selection -> every link is muted");
+
+const someBoxId = figure.boxIds[0];
+const boxSel = computeSankeyHighlight(links, figure.boxIds, { selectedBoxId: someBoxId, selectedLinkId: null }, colors);
+assert(
+  boxSel.nodeLineWidth[figure.boxIds.indexOf(someBoxId)] === 3,
+  "selected box's node line width is 3"
+);
+assert(
+  boxSel.nodeLineWidth.filter((w) => w === 3).length === 1,
+  "exactly one node is highlighted for a single selected box"
+);
+assert(boxSel.linkColor.every((c) => c === colors.muted), "selecting a box (not a link) leaves every link muted");
+
+// A selected link also outlines its two endpoint nodes (not just the link's
+// own color) -- a Sankey link has no non-color channel of its own, so
+// without this a selected link would be encoded by color alone (council
+// review gatekeeper finding, AGENTS.md "color isn't the sole encoding").
+const someLink = links[0];
+const linkSel = computeSankeyHighlight(links, figure.boxIds, { selectedBoxId: null, selectedLinkId: someLink.link_id }, colors);
+assert(linkSel.linkColor[0] === colors.accent, "selected link is accent-colored");
+assert(linkSel.linkColor.slice(1).every((c) => c === colors.muted), "every other link stays muted");
+const endpointIndices = [someLink.source_box_id, someLink.target_box_id].map((id) => figure.boxIds.indexOf(id));
+assert(
+  endpointIndices.every((i) => linkSel.nodeLineWidth[i] === 3),
+  "a selected link's two endpoint nodes are outlined"
+);
+assert(
+  linkSel.nodeLineWidth.filter((w) => w === 3).length === endpointIndices.length,
+  "only the selected link's own endpoints are outlined, nothing else"
+);
+
+// -- A box_id/link_id that isn't in this subset at all highlights nothing --
+const nothingSel = computeSankeyHighlight(links, figure.boxIds, { selectedBoxId: "NOT_A_REAL_BOX", selectedLinkId: "NOT_A_REAL_LINK" }, colors);
+assert(nothingSel.nodeLineWidth.every((w) => w === 0), "unknown selectedBoxId highlights nothing");
+assert(nothingSel.linkColor.every((c) => c === colors.muted), "unknown selectedLinkId highlights nothing");
+
+if (failures > 0) {
+  console.error(`\n${failures} assertion(s) failed.`);
+  process.exit(1);
+}
+console.log("\nAll assertions passed.");
diff --git a/projects/world-history/js/state.js b/projects/world-history/js/state.js
new file mode 100644
index 0000000..b550726
--- /dev/null
+++ b/projects/world-history/js/state.js
@@ -0,0 +1,42 @@
+// Shared application state. Deliberately tiny: a plain object, a set()
+// that merges a patch and notifies subscribers, and nothing else. See
+// docs/IMPLEMENTATION_PLAN.md Phase 2 for the field shapes this follows.
+
+const initialState = () => ({
+  selectedBoxId: null,
+  selectedSeaiId: null,
+  // Not in IMPLEMENTATION_PLAN.md Phase 2's suggested shape (that predates
+  // Links existing) -- added in Phase 3 so a clicked alluvial-diagram link
+  // can drive the same shared inspector as a clicked box.
+  selectedLinkId: null,
+  regionFilter: "all",
+  countryFilter: "all",
+  yearStart: -3000,
+  yearEnd: 2026,
+  widthMode: "equal",
+  showSeais: true,
+  // Phase 5.5 (docs/timescaleRequirement.md): the semantic-zoom slider's
+  // `s`, range [-2, 2], default 0. Shared by the timeline and the Sankey
+  // diagram -- see js/timescale.js's semanticTimeScale().
+  timeScale: 0,
+});
+
+export function createStore() {
+  let state = initialState();
+  const subscribers = new Set();
+
+  return {
+    get: () => state,
+    /** Shallow-merge `patch` into state, then notify every subscriber. */
+    set(patch) {
+      state = { ...state, ...patch };
+      for (const fn of subscribers) fn(state);
+    },
+    /** Call `fn(state)` on every change (and once immediately). Returns an unsubscribe function. */
+    subscribe(fn) {
+      subscribers.add(fn);
+      fn(state);
+      return () => subscribers.delete(fn);
+    },
+  };
+}
diff --git a/projects/world-history/js/timeline.js b/projects/world-history/js/timeline.js
new file mode 100644
index 0000000..41a331b
--- /dev/null
+++ b/projects/world-history/js/timeline.js
@@ -0,0 +1,227 @@
+// Timeline view (docs/IMPLEMENTATION_PLAN.md Phase 4). One horizontal bar per
+// box, in view, ordered chronologically -- a Gantt-style "descendant of the
+// source poster" per docs/VISUALIZATION.md View 1, not yet the poster's own
+// vertical-time/lane geometry (BoxSegments doesn't exist yet -- see
+// docs/STATUS.md limitation #3 -- so there's no real per-region lane to draw
+// beyond box_id order).
+//
+// Split the same way as js/sankey.js: a pure data transform
+// (buildTimelineLayout -- no D3/DOM dependency, Node-testable) and a
+// rendering function (renderTimeline -- needs a real browser and the D3 UMD
+// build loaded as window.d3).
+
+import { semanticTimeScale, timeTicks } from "./timescale.js";
+
+/**
+ * Compute which boxes are in view (region + year-range filtered), their bar
+ * extents, and which SEAIs to overlay. `state` is the shared store state
+ * (regionFilter, yearStart, yearEnd, showSeais, timeScale); `seaisByBoxId`
+ * is js/data.js's index.
+ *
+ * ISSUE-005: six boxes have no start_year (illegible "c. [BCE]" labels on
+ * the source poster). Rather than inventing a coordinate for them the way
+ * js/app.js's filteredBoxes() uses Number.NEGATIVE_INFINITY for *sort order*
+ * only, this places their bar's start at the left edge of whatever range is
+ * currently in view (`approxStart: true`; renderTimeline draws a dashed
+ * edge) -- an honest "starts sometime before this," not a fabricated date.
+ *
+ * Phase 5.5 (docs/timescaleRequirement.md): x-positions are no longer
+ * plain linear. `scale` (built here, once, from the current
+ * [domainStart, domainEnd, timeScale]) is the single source every
+ * time-based element in this view goes through -- box bars, SEAI markers,
+ * and axis ticks alike -- per that doc's "Shared Scale" requirement ("do
+ * not mix linear placement for some elements with semantic placement for
+ * others"). `ticks` is generated in calendar time first (candidate year
+ * values), then each is run through the same `scale` -- not the other way
+ * around -- per that doc's "Tick Generation" requirement.
+ */
+export function buildTimelineLayout(boxes, seaisByBoxId, state) {
+  const { regionFilter, yearStart, yearEnd, showSeais, timeScale } = state;
+  const domainStart = yearStart;
+  const domainEnd = yearEnd;
+  const scale = semanticTimeScale({ tMin: domainStart, tMax: domainEnd, scaler: timeScale ?? 0 });
+
+  const rows = boxes
+    .filter((b) => regionFilter === "all" || b.region_group === regionFilter)
+    .map((b) => {
+      const approxStart = b.start_year == null;
+      const effectiveStart = approxStart ? domainStart : b.start_year;
+      const end = b.end_year ?? domainEnd;
+      return { box: b, effectiveStart, end, approxStart };
+    })
+    // Drop boxes entirely outside the visible year range (rather than
+    // drawing an off-canvas or zero-width bar for them).
+    .filter((r) => r.end >= domainStart && r.effectiveStart <= domainEnd)
+    .sort((a, b) => a.effectiveStart - b.effectiveStart || a.end - b.end);
+
+  const rowIndexByBoxId = new Map(rows.map((r, i) => [r.box.box_id, i]));
+
+  // SEAIs without a numeric year (one, as of this dataset -- a text-only
+  // year_label like "Natural landmark") are silently skipped here rather
+  // than mis-plotted -- same "don't fabricate a coordinate" reasoning as
+  // approxStart above.
+  const seaiMarkers = showSeais
+    ? rows.flatMap((r) => {
+        const seais = seaisByBoxId.get(r.box.box_id) || [];
+        return seais
+          .filter((s) => typeof s.year === "number" && s.year >= domainStart && s.year <= domainEnd)
+          .map((s) => ({ seai: s, box_id: r.box.box_id, year: s.year }));
+      })
+    : [];
+
+  const ticks = timeTicks(domainStart, domainEnd).map((year) => ({ year, x: scale.yearToX(year) }));
+
+  return { domainStart, domainEnd, scale, rows, rowIndexByBoxId, seaiMarkers, ticks };
+}
+
+/**
+ * Render `layout` (from buildTimelineLayout) into `container` (a DOM
+ * element) using the D3 UMD build already loaded as `window.d3` (see
+ * index.html). Clicking a bar calls `onSelectBox(boxId)`.
+ *
+ * `state.linkHighlightBoxIds` (Phase 5, docs/IMPLEMENTATION_PLAN.md): an
+ * optional Set of box_ids to mark with the `.link-endpoint` class -- js/app.js
+ * fills this in from the selected alluvial link's source/target when one is
+ * selected, so choosing a link anywhere still lights something up here even
+ * though the timeline has no link geometry of its own to select.
+ *
+ * The container carries `role="img"` like js/sankey.js's #alluvial, but
+ * deliberately has no hidden fallback list of its own: unlike the Sankey
+ * links (which had no other accessible representation at all before
+ * Milestone 4), every box drawn here is already in the box list panel,
+ * which is fully keyboard-operable and drives the same shared
+ * `selectedBoxId` -- see index.html's timeline-note paragraph.
+ *
+ * Phase 5.5: the axis is drawn by hand (a `<line class="domain">` plus one
+ * `<g class="tick">` per `layout.ticks` entry) instead of `d3.axisBottom`,
+ * which assumes an invertible D3 scale object -- `layout.scale` is a plain
+ * `{ yearToX, xToYear, exponent }` (js/timescale.js), not one. Class names
+ * match what `d3.axisBottom` would have produced so css/history.css's
+ * existing `.timeline-axis .domain`/`.tick line`/`.tick text` rules still
+ * apply unchanged.
+ */
+export function renderTimeline(container, layout, state, { onSelectBox }) {
+  if (typeof window === "undefined" || !window.d3) {
+    throw new Error("D3 is not loaded (expected window.d3 on the page)");
+  }
+  const d3 = window.d3;
+  const { rows, rowIndexByBoxId, seaiMarkers, scale, ticks } = layout;
+
+  d3.select(container).selectAll("*").remove();
+
+  if (rows.length === 0) {
+    d3.select(container).append("p").attr("class", "timeline-empty").text("No boxes in this year range/region.");
+    return;
+  }
+
+  const rowHeight = 20;
+  const margin = { top: 8, right: 16, bottom: 28, left: 8 };
+  const width = Math.max(320, container.clientWidth || 800);
+  const innerWidth = width - margin.left - margin.right;
+  const height = margin.top + margin.bottom + rows.length * rowHeight;
+
+  // A box's real start/end may fall outside the currently filtered range
+  // (e.g. the Roman Empire when zoomed into 1000-1500); clamp the drawn bar
+  // to the visible plot area instead of letting it run off-canvas. (This
+  // also absorbs the rare floating-point overshoot at exactly domainStart/
+  // domainEnd -- scale.yearToX there is exactly 0/1, but a tick generated a
+  // hair past domainEnd by timeTicks' loop bound could land at e.g. 1.0000001.)
+  const xNorm = (x) => Math.min(innerWidth, Math.max(0, x * innerWidth));
+  const xClamped = (year) => xNorm(scale.yearToX(year));
+
+  const svg = d3
+    .select(container)
+    .append("svg")
+    .attr("width", width)
+    .attr("height", height)
+    .attr("viewBox", `0 0 ${width} ${height}`);
+
+  const plot = svg.append("g").attr("transform", `translate(${margin.left},${margin.top})`);
+
+  const axisGroup = plot
+    .append("g")
+    .attr("class", "timeline-axis")
+    .attr("transform", `translate(0,${rows.length * rowHeight})`);
+
+  axisGroup.append("line").attr("class", "domain").attr("x1", 0).attr("x2", innerWidth).attr("y1", 0.5).attr("y2", 0.5);
+
+  const tickSel = axisGroup
+    .selectAll("g.tick")
+    .data(ticks, (d) => d.year)
+    .join("g")
+    .attr("class", "tick")
+    // Reuse the x layout.ticks already computed (council review minor
+    // finding: recomputing scale.yearToX(d.year) here duplicated work --
+    // same value, since it's the same pure scale, just wasted).
+    .attr("transform", (d) => `translate(${xNorm(d.x)},0)`);
+  tickSel.append("line").attr("y2", 6);
+  tickSel
+    .append("text")
+    .attr("y", 9)
+    .attr("dy", "0.71em")
+    .attr("text-anchor", "middle")
+    .text((d) => formatTickYear(d.year));
+
+  const rowSel = plot
+    .selectAll("g.timeline-row")
+    .data(rows, (d) => d.box.box_id)
+    .join("g")
+    .attr("class", "timeline-row")
+    .attr("transform", (_, i) => `translate(0,${i * rowHeight})`)
+    .style("cursor", "pointer")
+    .on("click", (_event, d) => onSelectBox(d.box.box_id));
+
+  const linkHighlightBoxIds = state.linkHighlightBoxIds || null;
+  rowSel
+    .append("rect")
+    .attr(
+      "class",
+      (d) =>
+        "timeline-bar" +
+        (d.box.box_id === state.selectedBoxId ? " selected" : "") +
+        (linkHighlightBoxIds?.has(d.box.box_id) ? " link-endpoint" : "") +
+        (d.approxStart ? " approx-start" : "")
+    )
+    .attr("x", (d) => xClamped(d.effectiveStart))
+    .attr("y", 2)
+    .attr("width", (d) => Math.max(2, xClamped(d.end) - xClamped(d.effectiveStart)))
+    .attr("height", rowHeight - 6)
+    .attr("fill", (d) => d.box.color_hex || "#888888")
+    .append("title")
+    .text((d) => `${d.box.box_name} (${d.box.start_label ?? "?"}–${d.box.end_label ?? "?"})`);
+
+  // Diamond markers so SEAIs read as a distinct kind of thing from the boxes
+  // themselves by shape, not just by sitting on top of a box's color
+  // (AGENTS.md accessibility: color isn't the sole encoding).
+  plot
+    .selectAll("path.seai-marker")
+    .data(seaiMarkers, (d) => `${d.box_id}-${d.year}-${d.seai.name}`)
+    .join("path")
+    .attr("class", "seai-marker")
+    .attr("d", d3.symbol(d3.symbolDiamond, 36))
+    .attr("transform", (d) => {
+      const i = rowIndexByBoxId.get(d.box_id);
+      return `translate(${xClamped(d.year)},${i * rowHeight + rowHeight / 2})`;
+    })
+    .append("title")
+    .text((d) => `${d.seai.name} (${d.seai.year_label ?? d.year})`);
+}
+
+// docs/timescaleRequirement.md "Axis Labels and Interpretation": "retain
+// BCE/CE labels clearly" -- plain negative numbers (the previous
+// d3.format("d") behavior) don't read as history at a glance the way a
+// labeled era does, and that matters more now that pixel spacing is
+// nonlinear and so more easily misread as proportional to elapsed time.
+//
+// docs/DATA_MODEL.md: "There is no attempt to model a historical year
+// zero" -- js/timescale.js's timeTicks() already excludes an exact-0 tick
+// for that reason, but this function is also the obvious one to reuse for
+// a future hover/inspector display of an exact (possibly fractional) year
+// per the spec's own recommendation, so it guards year 0 (and the `-0`
+// Math.round(-0.4) can produce, which `rounded < 0` alone treats as
+// non-negative) itself rather than relying on the caller never passing it.
+function formatTickYear(year) {
+  const rounded = Math.round(year);
+  if (rounded === 0) return year < 0 ? "1 BCE" : "1 CE";
+  return rounded < 0 ? `${-rounded} BCE` : `${rounded} CE`;
+}
diff --git a/projects/world-history/js/timeline.test.mjs b/projects/world-history/js/timeline.test.mjs
new file mode 100644
index 0000000..23497ab
--- /dev/null
+++ b/projects/world-history/js/timeline.test.mjs
@@ -0,0 +1,112 @@
+// Committed, repeatable test for buildTimelineLayout() -- js/timeline.js's
+// pure data transform (no D3/DOM dependency, see that file's own comment).
+// Run with: node js/timeline.test.mjs
+//
+// This exists specifically to close ISSUE-009's recurring gap (Milestones
+// 2-4 each did real Node-based verification but only wrote it up as
+// commit-message/TRACEABILITY.md prose, never a committed test file).
+// renderTimeline() itself still isn't covered here -- that needs a real
+// browser/DOM and D3, which this environment doesn't have -- so this is a
+// partial, not complete, resolution of ISSUE-009 (see ISSUES.md).
+
+import { buildTimelineLayout } from "./timeline.js";
+import fs from "node:fs";
+import { fileURLToPath } from "node:url";
+
+const dataDir = fileURLToPath(new URL("../data/", import.meta.url));
+const boxes = JSON.parse(fs.readFileSync(dataDir + "boxes.json"));
+const seais = JSON.parse(fs.readFileSync(dataDir + "seais.json"));
+
+const seaisByBoxId = new Map();
+for (const s of seais) {
+  if (!seaisByBoxId.has(s.box_id)) seaisByBoxId.set(s.box_id, []);
+  seaisByBoxId.get(s.box_id).push(s);
+}
+
+let failures = 0;
+function assert(cond, msg) {
+  if (!cond) {
+    failures++;
+    console.error("FAIL:", msg);
+  } else {
+    console.log("ok:", msg);
+  }
+}
+
+// -- Default state (matches js/state.js's initialState()) --
+const defaultState = { regionFilter: "all", yearStart: -3000, yearEnd: 2026, showSeais: true, timeScale: 0 };
+const layout = buildTimelineLayout(boxes, seaisByBoxId, defaultState);
+
+assert(layout.rows.length > 0, "default state produces some rows");
+assert(layout.rows.length <= boxes.length, "rows never exceed box count");
+
+// -- Phase 5.5: shared semantic-zoom scale (docs/timescaleRequirement.md) --
+assert(typeof layout.scale?.yearToX === "function", "layout exposes a scale with yearToX");
+assert(layout.scale.yearToX(layout.domainStart) === 0, "scale.yearToX(domainStart) === 0");
+assert(layout.scale.yearToX(layout.domainEnd) === 1, "scale.yearToX(domainEnd) === 1");
+assert(Array.isArray(layout.ticks) && layout.ticks.length > 0, "layout exposes calendar-time-first ticks");
+assert(
+  layout.ticks.every((t) => typeof t.year === "number" && t.x === layout.scale.yearToX(t.year)),
+  "every tick's x matches the shared scale applied to its year"
+);
+for (let i = 1; i < layout.ticks.length; i++) {
+  assert(layout.ticks[i].x > layout.ticks[i - 1].x, "ticks strictly increase in x");
+}
+// A different timeScale slider value changes p (exponent), so at least one
+// row's effectiveStart should map to a different x than at s=0 -- confirms
+// buildTimelineLayout actually threads state.timeScale through, not just
+// state.yearStart/yearEnd.
+{
+  const zoomedLayout = buildTimelineLayout(boxes, seaisByBoxId, { ...defaultState, timeScale: 2 });
+  assert(zoomedLayout.scale.exponent() !== layout.scale.exponent(), "timeScale changes the scale's exponent");
+}
+
+// -- ISSUE-005: exactly the 6 known null-start_year boxes get approxStart --
+const approxRows = layout.rows.filter((r) => r.approxStart);
+const approxIds = approxRows.map((r) => r.box.box_id).sort();
+assert(
+  JSON.stringify(approxIds) === JSON.stringify(["AR_INDIG", "AU_INDIG", "CA_INDIG", "JP_JOMON", "UK_CELTIC", "US_INDIG"]),
+  `exactly the 6 known ISSUE-005 boxes are approxStart, got ${approxIds}`
+);
+for (const r of approxRows) {
+  assert(r.effectiveStart === defaultState.yearStart, `${r.box.box_id} effectiveStart clamps to domainStart`);
+}
+
+// -- Sort order --
+for (let i = 1; i < layout.rows.length; i++) {
+  assert(layout.rows[i - 1].effectiveStart <= layout.rows[i].effectiveStart, "rows sorted ascending by effectiveStart");
+}
+
+// -- Year-range filter: narrowing to 1900-2000 drops every approx-start box,
+// since all 6 have a real end_year (-300..1788) before 1900. --
+const narrow = buildTimelineLayout(boxes, seaisByBoxId, { regionFilter: "all", yearStart: 1900, yearEnd: 2000, showSeais: true });
+assert(narrow.rows.every((r) => r.end >= 1900 && r.effectiveStart <= 2000), "narrow range filters correctly");
+assert(narrow.rows.filter((r) => r.approxStart).length === 0, "approx-start boxes excluded once range starts after their real end_year");
+assert(narrow.rows.length < layout.rows.length, "narrow range has fewer rows than full range");
+
+// -- Region filter never mixes regions --
+const groups = [...new Set(boxes.map((b) => b.region_group).filter(Boolean))];
+const oneRegion = groups[0];
+const regionLayout = buildTimelineLayout(boxes, seaisByBoxId, { ...defaultState, regionFilter: oneRegion });
+assert(regionLayout.rows.every((r) => r.box.region_group === oneRegion), "region filter applies");
+assert(regionLayout.rows.length < layout.rows.length, "region filter narrows the set");
+
+// -- showSeais toggle --
+const noSeais = buildTimelineLayout(boxes, seaisByBoxId, { ...defaultState, showSeais: false });
+assert(noSeais.seaiMarkers.length === 0, "showSeais:false yields zero markers");
+assert(layout.seaiMarkers.length > 0, "showSeais:true yields some markers by default");
+assert(
+  layout.seaiMarkers.every((m) => typeof m.year === "number" && m.year >= layout.domainStart && m.year <= layout.domainEnd),
+  "all markers within domain"
+);
+
+// -- rowIndexByBoxId matches rows array --
+for (const [boxId, idx] of layout.rowIndexByBoxId) {
+  assert(layout.rows[idx].box.box_id === boxId, "rowIndexByBoxId matches rows array");
+}
+
+if (failures > 0) {
+  console.error(`\n${failures} assertion(s) failed.`);
+  process.exit(1);
+}
+console.log("\nAll assertions passed.");
diff --git a/projects/world-history/js/timescale.js b/projects/world-history/js/timescale.js
new file mode 100644
index 0000000..f864d10
--- /dev/null
+++ b/projects/world-history/js/timescale.js
@@ -0,0 +1,94 @@
+// Phase 5.5 (docs/IMPLEMENTATION_PLAN.md; full spec docs/timescaleRequirement.md):
+// a reusable, pure "semantic zoom" time scale. Every time-based visual
+// element sharing one view (js/timeline.js's box bars/SEAIs/ticks,
+// js/sankey.js's node placement, and later Phase 6's population knot
+// points) must go through this same module -- no element computing its own
+// separate linear normalization -- so a given [tMin, tMax, s] always puts a
+// given year at the same normalized x everywhere it's drawn.
+//
+// No D3/DOM/Plotly dependency -- Node-testable on its own, see
+// timescale.test.mjs.
+
+/**
+ * Build a scale for the visible window [tMin, tMax] at scale parameter
+ * `scaler` (the doc's `s`, range [-2, 2], default 0 -- "Ancient detail /
+ * Recent detail"). Returns `yearToX`/`xToYear`/`exponent`, matching the
+ * shape docs/timescaleRequirement.md's "Implementation Guidance" suggests.
+ *
+ * p = 1 / (1 + (M/3000) * 2^s)   -- the multiplicative form the spec
+ *                                   requires (never the additive
+ *                                   `1/(1+M/3000+s)`, which can hit a
+ *                                   zero/negative denominator for valid s)
+ * x = 1 - (a/M)^p                -- a = tMax - t, M = tMax - tMin
+ *
+ * `M` is clamped to a small positive epsilon internally so a degenerate
+ * zero-width view (yearStart === yearEnd, which js/app.js's own guard
+ * allows) can't divide by zero -- every date still maps to a finite,
+ * monotonic (if extreme) x instead of NaN.
+ *
+ * The `a >= 0` (t <= tMax) branch already covers t < tMin too (a > M just
+ * makes the ratio > 1, still a well-defined positive base for a fractional
+ * exponent), which is why boxes that start before the current viewport
+ * don't need special-casing. t > tMax needs its own branch purely to avoid
+ * raising a *negative* base to a fractional power (NaN) -- it mirrors the
+ * same shape on the other side of x = 1 so the whole function stays
+ * monotonic and continuous across the boundary.
+ */
+export function semanticTimeScale({ tMin, tMax, scaler = 0 }) {
+  const M = Math.max(0, tMax - tMin);
+  const s = Math.min(2, Math.max(-2, scaler));
+  const p = 1 / (1 + (M / 3000) * Math.pow(2, s));
+  const safeM = M > 0 ? M : 1e-9;
+
+  function yearToX(t) {
+    const a = tMax - t;
+    if (a >= 0) return 1 - Math.pow(a / safeM, p);
+    return 1 + Math.pow(-a / safeM, p);
+  }
+
+  function xToYear(x) {
+    if (x <= 1) return tMax - safeM * Math.pow(Math.max(0, 1 - x), 1 / p);
+    return tMax + safeM * Math.pow(x - 1, 1 / p);
+  }
+
+  return { yearToX, xToYear, exponent: () => p };
+}
+
+// Candidate tick intervals (years), covering everything from decade-scale
+// zoom-ins to the app's full -3000..2026 default span. Roughly matches
+// docs/timescaleRequirement.md's "Tick Generation" example table (a
+// 5000-year view landing on 500/1000-year ticks, etc.) without hardcoding
+// its exact numbers -- "exact tick-selection logic may be tuned for
+// readability" per that section.
+const TICK_INTERVALS = [1, 2, 5, 10, 20, 25, 50, 100, 200, 250, 500, 1000, 2000, 2500, 5000, 10000, 20000, 25000, 50000];
+
+/**
+ * Candidate tick years for the visible span [tMin, tMax], targeting ~10
+ * ticks. Generated in calendar time first (docs/timescaleRequirement.md
+ * "Tick Generation": "do not generate evenly spaced screen ticks and infer
+ * calendar years afterward") -- the caller runs each year through the same
+ * `semanticTimeScale` the rest of the view uses to get its screen position.
+ */
+export function timeTicks(tMin, tMax) {
+  const span = tMax - tMin;
+  if (!(span > 0)) return [tMin];
+  const target = span / 10;
+  const interval = TICK_INTERVALS.find((c) => c >= target) ?? TICK_INTERVALS[TICK_INTERVALS.length - 1];
+  const first = Math.ceil(tMin / interval) * interval;
+  const ticks = [];
+  for (let t = first; t <= tMax + 1e-9; t += interval) {
+    // docs/DATA_MODEL.md: "There is no attempt to model a historical year
+    // zero" -- every real box/SEAI year in this dataset is a nonzero
+    // integer (negative BCE, positive CE), so a tick landing on the
+    // interval arithmetic's year 0 (any span whose bounds straddle it, at
+    // an interval that divides evenly into it -- true for every interval
+    // in TICK_INTERVALS, so this hits the app's own default -3000..2026
+    // view) doesn't correspond to any calendar year this app's BCE/CE
+    // convention can label (council review gatekeeper finding: it was
+    // rendering as "0 CE", which isn't a real year under that convention).
+    // Simplest correct fix is to just not draw a tick there; the
+    // neighboring ticks on either side still anchor the axis.
+    if (t !== 0) ticks.push(t);
+  }
+  return ticks;
+}
diff --git a/projects/world-history/js/timescale.test.mjs b/projects/world-history/js/timescale.test.mjs
new file mode 100644
index 0000000..460b465
--- /dev/null
+++ b/projects/world-history/js/timescale.test.mjs
@@ -0,0 +1,117 @@
+// Committed, repeatable test for js/timescale.js -- the pure semantic-zoom
+// time scale (Phase 5.5, docs/timescaleRequirement.md). Covers exactly the
+// checks that doc's own "Validation" section calls out: boundary
+// conditions, monotonicity, round-trip, zoom behavior, and slider behavior.
+// Run with: node js/timescale.test.mjs
+
+import { semanticTimeScale, timeTicks } from "./timescale.js";
+
+let failures = 0;
+function assert(cond, msg) {
+  if (!cond) {
+    failures++;
+    console.error("FAIL:", msg);
+  } else {
+    console.log("ok:", msg);
+  }
+}
+function approx(a, b, eps = 1e-9) {
+  return Math.abs(a - b) <= eps;
+}
+
+// -- Boundary conditions --
+for (const scaler of [-2, -1, 0, 1, 2]) {
+  const scale = semanticTimeScale({ tMin: -3000, tMax: 2026, scaler });
+  assert(approx(scale.yearToX(-3000), 0), `yearToX(tMin) == 0 at s=${scaler}`);
+  assert(approx(scale.yearToX(2026), 1), `yearToX(tMax) == 1 at s=${scaler}`);
+}
+
+// -- Monotonicity, across viewport sizes and the full slider range, and
+// including years outside [tMin, tMax] (a box's real dates can run past
+// either edge of the currently visible window -- see js/timeline.js's
+// xClamped) --
+const windows = [
+  [-3000, 2026],
+  [0, 2026],
+  [1800, 2026],
+  [1990, 2000],
+  [500, 500 + 1e-6], // near-degenerate: still must not throw/NaN
+];
+for (const [tMin, tMax] of windows) {
+  for (const scaler of [-2, -1, 0, 0.5, 1, 2]) {
+    const scale = semanticTimeScale({ tMin, tMax, scaler });
+    const years = [tMin - 500, tMin, tMin + (tMax - tMin) / 3, (tMin + tMax) / 2, tMax - 1, tMax, tMax + 500];
+    for (let i = 1; i < years.length; i++) {
+      const t1 = years[i - 1];
+      const t2 = years[i];
+      if (t1 >= t2) continue; // near-degenerate window can collapse two sample points
+      const x1 = scale.yearToX(t1);
+      const x2 = scale.yearToX(t2);
+      assert(
+        Number.isFinite(x1) && Number.isFinite(x2) && x1 < x2,
+        `yearToX monotonic: t1=${t1} < t2=${t2} => x1=${x1} < x2=${x2} (window [${tMin},${tMax}], s=${scaler})`
+      );
+    }
+  }
+}
+
+// -- Round trip (representative years, including outside [tMin, tMax]) --
+{
+  const scale = semanticTimeScale({ tMin: -3000, tMax: 2026, scaler: 0 });
+  for (const t of [-3000, -2500, -1000, 0, 537, 1000, 1800, 1990, 2026, -4000, 2100]) {
+    const roundTripped = scale.xToYear(scale.yearToX(t));
+    assert(approx(roundTripped, t, 1e-6), `xToYear(yearToX(${t})) ≈ ${t}, got ${roundTripped}`);
+  }
+}
+
+// -- Zoom behavior: at s=0, M=3000 -> p=0.5; M -> 0 -> p -> 1 --
+assert(approx(semanticTimeScale({ tMin: 0, tMax: 3000, scaler: 0 }).exponent(), 0.5), "M=3000, s=0 => p=0.5");
+assert(semanticTimeScale({ tMin: 0, tMax: 1, scaler: 0 }).exponent() > 0.99, "M near 0 => p near 1 (linear)");
+
+// -- Slider behavior: s decreases -> p increases (more linear); s increases
+// -> p decreases (recent history gets more room) --
+{
+  const M = 6000;
+  const pByScaler = [-2, -1, 0, 1, 2].map((s) => semanticTimeScale({ tMin: 0, tMax: M, scaler: s }).exponent());
+  for (let i = 1; i < pByScaler.length; i++) {
+    assert(pByScaler[i] < pByScaler[i - 1], `p strictly decreases as s increases (index ${i}: ${pByScaler[i]} < ${pByScaler[i - 1]})`);
+  }
+}
+
+// -- Coordinate stability: exponent depends only on [tMin, tMax, s], not on
+// anything else -- trivially true here since the function signature has no
+// other inputs, but assert the two scale instances agree exactly. --
+{
+  const a = semanticTimeScale({ tMin: -500, tMax: 1500, scaler: 1 });
+  const b = semanticTimeScale({ tMin: -500, tMax: 1500, scaler: 1 });
+  assert(a.exponent() === b.exponent(), "same [tMin,tMax,s] => same exponent");
+  assert(a.yearToX(537) === b.yearToX(537), "same [tMin,tMax,s] => same yearToX for a given year");
+}
+
+// -- timeTicks: calendar-time-first tick generation --
+{
+  const ticks = timeTicks(-3000, 2026);
+  assert(ticks.length > 0, "timeTicks produces at least one tick for a real span");
+  assert(ticks.every((t) => t >= -3000 && t <= 2026), "every tick falls within [tMin, tMax]");
+  for (let i = 1; i < ticks.length; i++) {
+    assert(ticks[i] > ticks[i - 1], "ticks are strictly increasing");
+  }
+  const narrowTicks = timeTicks(1990, 2000);
+  assert(narrowTicks.length > 0, "timeTicks handles a narrow span without throwing");
+  assert(timeTicks(500, 500).length === 1, "zero-width span falls back to a single tick, not a crash/empty array");
+
+  // docs/DATA_MODEL.md: "There is no attempt to model a historical year
+  // zero" -- a span whose calendar-arithmetic ticks would otherwise land
+  // exactly on 0 (the app's own default -3000..2026 view is exactly this
+  // case) must not produce one; there's no real calendar year to label it
+  // with (council review gatekeeper finding -- js/timeline.js's
+  // formatTickYear was rendering it as "0 CE").
+  assert(!ticks.includes(0), "timeTicks never includes year 0 (no historical year zero)");
+  assert(!timeTicks(-500, 500).includes(0), "a span straddling 0 at a smaller interval still excludes it");
+}
+
+if (failures > 0) {
+  console.error(`\n${failures} assertion(s) failed.`);
+  process.exit(1);
+}
+console.log("\nAll assertions passed.");
diff --git a/projects/world-history/package.json b/projects/world-history/package.json
new file mode 100644
index 0000000..88394b2
--- /dev/null
+++ b/projects/world-history/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "world-history",
+  "private": true,
+  "type": "module",
+  "description": "No build step for the site itself -- index.html loads js/*.js directly as browser <script type=\"module\">, and this file changes nothing about that. It exists solely so `node js/timeline.test.mjs` can import ./timeline.js as an ES module (Node otherwise defaults a bare .js file to CommonJS, which can't parse `export`)."
+}
diff --git a/projects/world-history/source/world_history_chart_dataset_v2.xlsx b/projects/world-history/source/world_history_chart_dataset_v2.xlsx
new file mode 100644
index 0000000..c0c2f89
Binary files /dev/null and b/projects/world-history/source/world_history_chart_dataset_v2.xlsx differ
diff --git a/projects/world-history/tools/README.md b/projects/world-history/tools/README.md
new file mode 100644
index 0000000..ec41140
--- /dev/null
+++ b/projects/world-history/tools/README.md
@@ -0,0 +1,38 @@
+# tools/
+
+Build-time scripts only. Nothing here runs in production — the deployed site
+only ever reads the generated JSON in `data/`.
+
+- `wh_data.py` — shared loading/validation library (workbook -> row dicts,
+  the validation rules, and the ERROR/WARNING severity policy). Imported by
+  both scripts below; not a CLI itself.
+- `build_data.py` — reads `source/*.xlsx`, validates it, and writes
+  `data/*.json`. Fails (exit 1, writes nothing) if validation finds any
+  ERROR-level problem; warnings are printed but don't block the build.
+  ```
+  python3 tools/build_data.py
+  ```
+- `validate_data.py` — same validation as `build_data.py`, but only reports;
+  writes nothing. Useful as a quick check on the workbook alone.
+  ```
+  python3 tools/validate_data.py
+  ```
+
+Both accept `--source <path>`; `build_data.py` also accepts `--out <dir>`.
+Their default paths are relative to this project directory
+(`projects/world-history/`), so run them with that as the working directory:
+
+```
+cd projects/world-history
+python3 tools/build_data.py
+```
+
+Requires `openpyxl` (`pip install -r tools/requirements.txt`).
+
+Run `validate_data.py` (or `build_data.py`, which validates first) after any
+edit to the workbook, and regenerate `data/*.json` before committing a
+workbook change. `data/*.json` should always be reproducible from
+`source/*.xlsx` — if it isn't, that's a bug in these scripts, not something
+to hand-patch in `data/`.
+
+See `docs/IMPLEMENTATION_PLAN.md` Phase 1.
diff --git a/projects/world-history/tools/build_data.py b/projects/world-history/tools/build_data.py
new file mode 100644
index 0000000..ef5f7ea
--- /dev/null
+++ b/projects/world-history/tools/build_data.py
@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+"""Build data/*.json from source/*.xlsx.
+
+Build-time only -- nothing in this script or its output requires a server.
+See docs/IMPLEMENTATION_PLAN.md Phase 1.
+
+Usage:
+    python3 tools/build_data.py
+    python3 tools/build_data.py --source source/world_history_chart_dataset_v2.xlsx --out data
+
+Exits non-zero and writes nothing if validation finds any ERROR-level problem
+(see tools/wh_data.py for the severity policy). Warnings are printed but do
+not block the build.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+import wh_data  # noqa: E402
+
+# Maps sheet name -> output filename. BoxSegments isn't in the workbook yet
+# (see docs/DATA_MODEL.md #6) so it isn't produced here.
+OUTPUTS = {
+    "Boxes": "boxes.json",
+    "SEAIs": "seais.json",
+    "Population": "population.json",
+    "Regions": "regions.json",
+    "Links": "links.json",
+}
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--source", default="source/world_history_chart_dataset_v2.xlsx")
+    parser.add_argument("--out", default="data")
+    args = parser.parse_args()
+
+    source_path = Path(args.source)
+    if not source_path.exists():
+        print(f"error: source workbook not found: {source_path}", file=sys.stderr)
+        return 1
+
+    tables = wh_data.load_workbook(str(source_path))
+    report = wh_data.validate_all(tables)
+
+    for w in report.warnings:
+        print(f"warning: {w}", file=sys.stderr)
+    for e in report.errors:
+        print(f"error: {e}", file=sys.stderr)
+
+    counts = {name: len(rows) for name, rows in tables.items()}
+    print(f"loaded: {counts}", file=sys.stderr)
+    print(f"{len(report.warnings)} warning(s), {len(report.errors)} error(s)", file=sys.stderr)
+
+    if not report.ok:
+        print("build FAILED: fix the error(s) above before data/*.json is regenerated", file=sys.stderr)
+        return 1
+
+    out_dir = Path(args.out)
+    out_dir.mkdir(parents=True, exist_ok=True)
+    for sheet_name, filename in OUTPUTS.items():
+        out_path = out_dir / filename
+        with out_path.open("w", encoding="utf-8") as f:
+            json.dump(tables[sheet_name], f, indent=2, ensure_ascii=False, sort_keys=False)
+            f.write("\n")
+        print(f"wrote {out_path} ({len(tables[sheet_name])} rows)", file=sys.stderr)
+
+    print("build OK", file=sys.stderr)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/projects/world-history/tools/requirements.txt b/projects/world-history/tools/requirements.txt
new file mode 100644
index 0000000..4a16a09
--- /dev/null
+++ b/projects/world-history/tools/requirements.txt
@@ -0,0 +1 @@
+openpyxl>=3.1,<4
diff --git a/projects/world-history/tools/validate_data.py b/projects/world-history/tools/validate_data.py
new file mode 100644
index 0000000..843b2c1
--- /dev/null
+++ b/projects/world-history/tools/validate_data.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+"""Validate source/*.xlsx without writing anything to data/.
+
+Useful as a fast pre-commit check on the workbook alone. build_data.py runs
+the same validation before it writes JSON; this script exists for the case
+where you just want the report. See docs/IMPLEMENTATION_PLAN.md Phase 1.
+
+Usage:
+    python3 tools/validate_data.py
+    python3 tools/validate_data.py --source source/world_history_chart_dataset_v2.xlsx
+"""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+import wh_data  # noqa: E402
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--source", default="source/world_history_chart_dataset_v2.xlsx")
+    args = parser.parse_args()
+
+    source_path = Path(args.source)
+    if not source_path.exists():
+        print(f"error: source workbook not found: {source_path}", file=sys.stderr)
+        return 1
+
+    tables = wh_data.load_workbook(str(source_path))
+    report = wh_data.validate_all(tables)
+
+    counts = {name: len(rows) for name, rows in tables.items()}
+    print(f"loaded: {counts}")
+    for w in report.warnings:
+        print(f"warning: {w}")
+    for e in report.errors:
+        print(f"error: {e}")
+    print(f"{len(report.warnings)} warning(s), {len(report.errors)} error(s)")
+
+    if not report.ok:
+        print("VALIDATION FAILED")
+        return 1
+
+    print("VALIDATION OK")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/projects/world-history/tools/wh_data.py b/projects/world-history/tools/wh_data.py
new file mode 100644
index 0000000..a28de6e
--- /dev/null
+++ b/projects/world-history/tools/wh_data.py
@@ -0,0 +1,344 @@
+"""Shared loading/validation for the World History Explorer data pipeline.
+
+Used by build_data.py (loads -> validates -> writes data/*.json) and
+validate_data.py (loads -> validates -> reports, writes nothing). Keeping the
+logic here means both scripts see exactly the same rules.
+
+This module is build-time only. Nothing here ships to the browser.
+
+Severity policy (see docs/DATA_MODEL.md #8 and docs/IMPLEMENTATION_PLAN.md
+Phase 1):
+
+- ERROR  = structural problem (duplicate/missing ID, broken foreign key,
+  malformed year, invalid numeric population, inconsistent low/high bounds).
+  The build must fail rather than emit generated JSON that can't be trusted.
+- WARNING = content-quality flag (TODO URLs, missing population, low/unknown
+  confidence, off-vocabulary values not yet reconciled with docs/DATA_MODEL.md's
+  recommended lists, suspicious dates). These are expected at this stage of
+  the project and are not blockers.
+"""
+
+from __future__ import annotations
+
+import math
+import re
+from dataclasses import dataclass, field
+
+import openpyxl
+
+TODO_URL = "https://en.wikipedia.org/wiki/Time_management#Implementation_of_goals"
+
+HEX_RE = re.compile(r"^#[0-9A-Fa-f]{6}$")
+
+# Recommended/expected controlled vocabularies. Values outside these are
+# WARNed on, not rejected -- the workbook is allowed to be ahead of the docs.
+CONFIDENCE_LEVELS = {"High", "Medium", "Low", "Unknown"}
+POPULATION_STATUS = {"TODO", "Estimated", "Verified"}
+POPULATION_BASIS_RECOMMENDED = {
+    "polity_total",
+    "territorial_segment",
+    "modern_country_total",
+    "other",
+}
+# "TBD" is the workbook's own placeholder for basis/method, distinct from the
+# recommended vocabulary above -- treated like the TODO URL: expected for now.
+PLACEHOLDER_BASIS_METHOD = "TBD"
+
+# docs/DATA_MODEL.md #5 "Recommended relation types". Unlike the vocabularies
+# above, docs/IMPLEMENTATION_PLAN.md Phase 1 explicitly lists "invalid
+# relation types" among the build-failing checks, so this one is ERROR, not
+# WARNING -- see validate_links.
+RELATION_TYPES = {
+    "successor",
+    "partition",
+    "unification",
+    "conquest",
+    "colonization",
+    "decolonization",
+    "dynastic_transition",
+    "institutional_successor",
+    "cultural_continuity",
+    "migration",
+    "other",
+}
+
+SHEETS = {
+    "Boxes": {"header_row": 1},
+    "SEAIs": {"header_row": 1},
+    "Population": {"header_row": 3},
+    "Regions": {"header_row": 3},
+    "Links": {"header_row": 1},
+}
+
+
+@dataclass
+class Report:
+    errors: list[str] = field(default_factory=list)
+    warnings: list[str] = field(default_factory=list)
+
+    def error(self, msg: str) -> None:
+        self.errors.append(msg)
+
+    def warn(self, msg: str) -> None:
+        self.warnings.append(msg)
+
+    @property
+    def ok(self) -> bool:
+        return not self.errors
+
+
+def _clean(value):
+    """Normalize a raw cell value: strip strings, blank string -> None."""
+    if isinstance(value, str):
+        value = value.strip()
+        return value or None
+    return value
+
+
+def load_sheet(wb, name: str) -> list[dict]:
+    header_row = SHEETS[name]["header_row"]
+    ws = wb[name]
+    header = list(next(ws.iter_rows(min_row=header_row, max_row=header_row, values_only=True)))
+    rows = []
+    for raw in ws.iter_rows(min_row=header_row + 1, values_only=True):
+        if all(c is None for c in raw):
+            continue  # skip fully blank rows
+        rows.append({col: _clean(v) for col, v in zip(header, raw) if col is not None})
+    return rows
+
+
+def load_workbook(path: str) -> dict[str, list[dict]]:
+    wb = openpyxl.load_workbook(path, data_only=True)
+    missing = [name for name in SHEETS if name not in wb.sheetnames]
+    if missing:
+        raise ValueError(f"workbook is missing expected sheet(s): {missing}")
+    return {name: load_sheet(wb, name) for name in SHEETS}
+
+
+def _is_number(value) -> bool:
+    return isinstance(value, (int, float)) and not isinstance(value, bool)
+
+
+def validate_boxes(boxes: list[dict], report: Report) -> dict[str, dict]:
+    by_id: dict[str, dict] = {}
+    seen_ids: set[str] = set()
+    for row in boxes:
+        box_id = row.get("box_id")
+        if not box_id:
+            report.error(f"Boxes: row missing box_id: {row!r}")
+            continue
+        if box_id in seen_ids:
+            report.error(f"Boxes: duplicate box_id '{box_id}'")
+        seen_ids.add(box_id)
+        by_id[box_id] = row
+
+        for field_name in ("start_year", "end_year"):
+            v = row.get(field_name)
+            if v is not None and not _is_number(v):
+                report.error(f"Boxes[{box_id}]: malformed {field_name} = {v!r}")
+
+        sy, ey = row.get("start_year"), row.get("end_year")
+        if _is_number(sy) and _is_number(ey) and sy > ey:
+            report.error(f"Boxes[{box_id}]: start_year ({sy}) > end_year ({ey})")
+
+        color_hex = row.get("color_hex")
+        if not color_hex or not HEX_RE.match(str(color_hex)):
+            report.error(f"Boxes[{box_id}]: invalid color_hex {color_hex!r}")
+
+        confidence = row.get("confidence")
+        if confidence not in CONFIDENCE_LEVELS:
+            report.warn(f"Boxes[{box_id}]: confidence {confidence!r} outside {sorted(CONFIDENCE_LEVELS)}")
+
+        url = row.get("url")
+        if not url:
+            report.error(f"Boxes[{box_id}]: missing url (should at least hold the TODO placeholder)")
+        elif url == TODO_URL:
+            report.warn(f"Boxes[{box_id}]: url is still the TODO placeholder")
+
+    return by_id
+
+
+def validate_seais(seais: list[dict], box_ids: set[str], report: Report) -> None:
+    seen_ids: set[str] = set()
+    for row in seais:
+        seai_id = row.get("seai_id")
+        if not seai_id:
+            report.error(f"SEAIs: row missing seai_id: {row!r}")
+            continue
+        if seai_id in seen_ids:
+            report.error(f"SEAIs: duplicate seai_id '{seai_id}'")
+        seen_ids.add(seai_id)
+
+        box_id = row.get("box_id")
+        if not box_id:
+            report.error(f"SEAIs[{seai_id}]: missing box_id")
+        elif box_id not in box_ids:
+            report.error(f"SEAIs[{seai_id}]: box_id '{box_id}' does not exist in Boxes")
+
+        for field_name in ("year", "historical_year"):
+            v = row.get(field_name)
+            if v is not None and not _is_number(v):
+                report.error(f"SEAIs[{seai_id}]: malformed {field_name} = {v!r}")
+
+        confidence = row.get("confidence")
+        if confidence not in CONFIDENCE_LEVELS:
+            report.warn(f"SEAIs[{seai_id}]: confidence {confidence!r} outside {sorted(CONFIDENCE_LEVELS)}")
+
+        url = row.get("url")
+        if not url:
+            report.error(f"SEAIs[{seai_id}]: missing url (should at least hold the TODO placeholder)")
+        elif url == TODO_URL:
+            report.warn(f"SEAIs[{seai_id}]: url is still the TODO placeholder")
+
+
+def validate_population(pop: list[dict], box_ids: set[str], report: Report) -> None:
+    seen_ids: set[str] = set()
+    seen_knots: dict[tuple, int] = {}
+    for row in pop:
+        pid = row.get("population_id")
+        if not pid:
+            report.error(f"Population: row missing population_id: {row!r}")
+            continue
+        if pid in seen_ids:
+            report.error(f"Population: duplicate population_id '{pid}'")
+        seen_ids.add(pid)
+
+        box_id = row.get("box_id")
+        if not box_id:
+            report.error(f"Population[{pid}]: missing box_id")
+        elif box_id not in box_ids:
+            report.error(f"Population[{pid}]: box_id '{box_id}' does not exist in Boxes")
+
+        year = row.get("year")
+        if year is not None and not _is_number(year):
+            report.error(f"Population[{pid}]: malformed year = {year!r}")
+
+        knot = (box_id, year, row.get("sample_type"))
+        if knot in seen_knots:
+            report.warn(f"Population[{pid}]: duplicate knot point {knot} (also row {seen_knots[knot]!r})")
+        else:
+            seen_knots[knot] = pid
+
+        population = row.get("population")
+        low, high = row.get("population_low"), row.get("population_high")
+        if population is None:
+            report.warn(f"Population[{pid}]: population not yet filled")
+        else:
+            if not _is_number(population):
+                report.error(f"Population[{pid}]: malformed population = {population!r}")
+            elif population <= 0:
+                report.error(f"Population[{pid}]: population must be > 0, got {population}")
+            if _is_number(low) and _is_number(population) and low > population:
+                report.error(f"Population[{pid}]: population_low ({low}) > population ({population})")
+            if _is_number(high) and _is_number(population) and population > high:
+                report.error(f"Population[{pid}]: population ({population}) > population_high ({high})")
+
+        status = row.get("status")
+        if status not in POPULATION_STATUS:
+            report.warn(f"Population[{pid}]: status {status!r} outside {sorted(POPULATION_STATUS)}")
+
+        for field_name in ("population_basis", "estimate_method"):
+            v = row.get(field_name)
+            if v is not None and v != PLACEHOLDER_BASIS_METHOD and field_name == "population_basis" and v not in POPULATION_BASIS_RECOMMENDED:
+                report.warn(f"Population[{pid}]: {field_name} {v!r} outside recommended vocabulary {sorted(POPULATION_BASIS_RECOMMENDED)}")
+
+
+def validate_regions(regions: list[dict], report: Report) -> None:
+    seen_pairs: set[tuple] = set()
+    for row in regions:
+        region_id, country = row.get("region_id"), row.get("country")
+        if not region_id or not row.get("region_name") or not country:
+            report.error(f"Regions: row missing region_id/region_name/country: {row!r}")
+            continue
+        pair = (region_id, country)
+        if pair in seen_pairs:
+            report.error(f"Regions: duplicate (region_id, country) pair {pair}")
+        seen_pairs.add(pair)
+
+
+def validate_links(links: list[dict], boxes_by_id: dict[str, dict], report: Report) -> None:
+    seen_ids: set[str] = set()
+    for row in links:
+        link_id = row.get("link_id")
+        if not link_id:
+            report.error(f"Links: row missing link_id: {row!r}")
+            continue
+        if link_id in seen_ids:
+            report.error(f"Links: duplicate link_id '{link_id}'")
+        seen_ids.add(link_id)
+
+        source_id, target_id = row.get("source_box_id"), row.get("target_box_id")
+        source_box = boxes_by_id.get(source_id) if source_id else None
+        target_box = boxes_by_id.get(target_id) if target_id else None
+        if not source_id:
+            report.error(f"Links[{link_id}]: missing source_box_id")
+        elif source_box is None:
+            report.error(f"Links[{link_id}]: source_box_id '{source_id}' does not exist in Boxes")
+        if not target_id:
+            report.error(f"Links[{link_id}]: missing target_box_id")
+        elif target_box is None:
+            report.error(f"Links[{link_id}]: target_box_id '{target_id}' does not exist in Boxes")
+
+        year = row.get("year")
+        if year is not None and not _is_number(year):
+            report.error(f"Links[{link_id}]: malformed year = {year!r}")
+
+        # docs/IMPLEMENTATION_PLAN.md Phase 1 explicitly fails the build on
+        # "invalid relation types" -- ERROR, unlike the WARN-level vocabulary
+        # checks elsewhere in this file (see RELATION_TYPES comment above).
+        relation_type = row.get("relation_type")
+        if not relation_type:
+            report.error(f"Links[{link_id}]: missing relation_type")
+        elif relation_type not in RELATION_TYPES:
+            report.error(f"Links[{link_id}]: relation_type {relation_type!r} not in {sorted(RELATION_TYPES)}")
+
+        # "Transition year sensible" (docs/DATA_MODEL.md #8) is a content-
+        # quality check, not structural -- WARN rather than ERROR.
+        if _is_number(year) and source_box is not None and target_box is not None:
+            lo = min(v for v in (source_box.get("start_year"), target_box.get("start_year")) if _is_number(v))
+            hi = max(v for v in (source_box.get("end_year"), target_box.get("end_year")) if _is_number(v))
+            if not (lo <= year <= hi):
+                report.warn(
+                    f"Links[{link_id}]: year {year} falls outside the source/target boxes' "
+                    f"combined span [{lo}, {hi}]"
+                )
+
+        confidence = row.get("confidence")
+        if confidence not in CONFIDENCE_LEVELS:
+            report.warn(f"Links[{link_id}]: confidence {confidence!r} outside {sorted(CONFIDENCE_LEVELS)}")
+
+        url = row.get("source_url")
+        if not url:
+            report.warn(f"Links[{link_id}]: missing source_url")
+        elif url == TODO_URL:
+            report.warn(f"Links[{link_id}]: source_url is still the TODO placeholder")
+
+
+def compute_log10_population(pop: list[dict], report: Report) -> None:
+    """Recompute log10_population from population at build time -- it's a
+    derived field per docs/DATA_MODEL.md, not hand-authored."""
+    for row in pop:
+        population = row.get("population")
+        if _is_number(population) and population > 0:
+            computed = round(math.log10(population), 4)
+            existing = row.get("log10_population")
+            if _is_number(existing) and abs(existing - computed) > 1e-3:
+                report.warn(
+                    f"Population[{row.get('population_id')}]: workbook log10_population "
+                    f"{existing} does not match computed {computed}; overwriting with computed value"
+                )
+            row["log10_population"] = computed
+        else:
+            row["log10_population"] = None
+
+
+def validate_all(tables: dict[str, list[dict]]) -> Report:
+    report = Report()
+    boxes_by_id = validate_boxes(tables["Boxes"], report)
+    box_ids = set(boxes_by_id)
+    validate_seais(tables["SEAIs"], box_ids, report)
+    validate_population(tables["Population"], box_ids, report)
+    validate_regions(tables["Regions"], report)
+    validate_links(tables["Links"], boxes_by_id, report)
+    compute_log10_population(tables["Population"], report)
+    return report