fix(nelson): increase content width to accommodate 728px ads

[faisalahammad]

Summary

Newspack Nelson's #primary has extra horizontal padding (3rem per side at desktop) that narrows the content area to ~702px, preventing 728px wide ads from fitting. Reducing desktop padding to 2rem per side brings the content width to >= 728px.

Fixes #1527

Changes

newspack-nelson/sass/style.scss

Before:

@include utilities.media( desktop ) {
    padding-left: #{3 * structure.$size__spacing-unit};
    padding-right: #{3 * structure.$size__spacing-unit};
}

After:

@include utilities.media( desktop ) {
    padding-left: #{2 * structure.$size__spacing-unit};
    padding-right: #{2 * structure.$size__spacing-unit};
}

Why: 3rem (48px) padding per side at desktop was Nelson-specific — no other child theme adds padding to #primary. Reducing to 2rem (32px) matches the tablet breakpoint value and gives .main-content enough width for 728px ads while keeping the visual difference minimal.

Testing

1. Activate Newspack Nelson theme
2. Open a single post with sidebar at desktop viewport (>= 1200px)
3. Inspect .main-content — computed width should be >= 728px
4. Verify tablet/mobile padding unchanged (2rem at tablet, 0 at mobile)

Build

newspack-nelson-fix-1527.zip available for manual testing. Install via WP Admin -> Appearance -> Themes -> Upload Theme.