## Summary
Fixes#20689
Previously, `@layer` blocks were not being processed through the CSS
minifier, which meant that `color-scheme` properties inside `@layer`
blocks would not get the required `--buncss-light`/`--buncss-dark`
variable injections needed for browsers that don't support the
`light-dark()` function.
## Changes
- Implemented proper minification for `LayerBlockRule` in
`src/css/rules/rules.zig:218-221`
- Added recursive call to `minify()` on nested rules, matching the
behavior of other at-rules like `@media` and `@supports`
- Added comprehensive tests for `color-scheme` inside `@layer` blocks
## Test Plan
Added three new test cases in `test/js/bun/css/css.test.ts`:
1. Simple `@layer` with `color-scheme: dark`
2. Named layers (`@layer shm.colors`) with multiple rules
3. Anonymous `@layer` with `color-scheme: light dark` (generates media
query)
All tests pass:
```bash
bun bd test test/js/bun/css/css.test.ts -t "color-scheme"
```
## Before
```css
/* Input */
@layer shm.colors {
body.theme-dark {
color-scheme: dark;
}
}
/* Output (broken - no variables) */
@layer shm.colors {
body.theme-dark {
color-scheme: dark;
}
}
```
## After
```css
/* Input */
@layer shm.colors {
body.theme-dark {
color-scheme: dark;
}
}
/* Output (fixed - variables injected) */
@layer shm.colors {
body.theme-dark {
--buncss-light: ;
--buncss-dark: initial;
color-scheme: dark;
}
}
```
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
