Plan step 36 review of 76abdd62. The old view put the filled variant's
16px padding on its own summary and body; the stylesheet matched them as
descendants of any filled collapse, so a plain collapse nested inside
one took the padding too (and an open one turned every nested chevron).
Child combinators now tie each rule to its own <details>. The 12px gap is
a literal like alert.css's, not an average of two spacing tokens.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
Plan step 36 (containment group): <x-collapse>'s Tailwind-era
resources/css/components/collapse.css (the height animation, C-24)
becomes the plain stylesheet, keyed on data-md-collapse and
data-md-variant; the summary renders the shared md-state-layer and
md-focus-ring classes instead of copying their rules. Leaves
tailwind.css for the Containment block of components.css.
Icon-to-title and title-to-chevron gaps stay 12px (not an M3 number;
collapse isn't an M3 component), written as the average of the two
adjacent spacing steps since the scale has no exact token for it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
Plan step 19, containment.md C-24. `interpolate-size: allow-keywords`
was set and nothing transitioned, so the content snapped open. A new
resources/css/components/collapse.css transitions `block-size` on
`::details-content` over the fast spatial spring, with
`content-visibility` `allow-discrete` beside it so the section stays
rendered while it closes. The `<details>` carries `data-collapse` for
the rule to find.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
