Add Tailwind HTML embed build

CHANGELOG.md

@@ -8,6 +8,7 @@ Format loosely follows [Keep a Changelog](https://keepachangelog.com).
 ## [Unreleased]
 
 ### Added
+- HTML iframe embeds can now be built into `.dist.html` files with pruned Tailwind v4 CSS.
 
 ### Changed
 

README.md

@@ -81,6 +81,22 @@ pnpm check            # run Biome
 pnpm typecheck        # typecheck all packages
 ```
 
+## HTML App Tailwind builds
+
+For local HTML Apps or iframe Embeds that use Tailwind utilities, build a static artifact instead of loading Tailwind at runtime:
+
+```sh
+pnpm --filter @hubble.md/desktop build:html-embed path/to/file-index.html
+```
+
+The default output is `path/to/file-index.dist.html`. Point Markdown embeds at the built file:
+
+```html
+<iframe src="./file-index.dist.html"></iframe>
+```
+
+The builder scans the source HTML class attributes, compiles Tailwind v4 CSS for those candidates only, and inlines the result into the output HTML.
+
 ## Documentation
 
 - [`CONTRIBUTING.md`](./CONTRIBUTING.md) covers the contribution flow, local setup, and pre-PR checks.
@@ -95,4 +111,4 @@ This project follows our [Code of Conduct](./CODE_OF_CONDUCT.md). To report a se
 
 ## License
 
-Hubble.md is licensed under the [MIT License](./LICENSE).
+Hubble.md is licensed under the [MIT License](./LICENSE).

apps/desktop/fixtures/playground/README.md

@@ -3,3 +3,9 @@
 This workspace is copied into `.dev-electron/playground` for local Electron dev runs.
 
 Open `file-index.html` or `todo-demo.html` in Hubble to test full-screen HTML Apps.
+
+`tailwind-card.html` is the source file for a Tailwind-built iframe Embed. Rebuild it with:
+
+```sh
+pnpm --filter @hubble.md/desktop build:html-embed apps/desktop/fixtures/playground/tailwind-card.html
+```

apps/desktop/fixtures/playground/project-ideas.md

@@ -12,4 +12,6 @@ Use this note to test **bold text**, *italic text*, `inline code`, [[effective-l
 
 Open `file-index.html` or `todo-demo.html` from the sidebar to try full-screen HTML Apps. See [[samples/interview-prep]] for prompts.
 
+<iframe src="./tailwind-card.dist.html"></iframe>
+
 ![Project sketch](project-ideas.assets/project-sketch.jpg)