Firefox 146 adds CSS @custom-media at-rule behind flag
#28438
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Co-authored-by: Claas Augner <495429+caugner@users.noreply.github.com>
Co-authored-by: Claas Augner <495429+caugner@users.noreply.github.com>
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@custom-media at-rule@custom-media at-rule behind flag
Relates to mdn#28438 This PR adds `CSSCustomMediaRule` API. Ref: * mozilla-firefox/firefox@f289eebba919#diff-5344d883f252f0d0fcde1443e722366428c6dec715f2dfa5a910d6d4fd088ce2 * https://bugzilla.mozilla.org/show_bug.cgi?id=1744292
* Firefox 146 adds `CSSCustomMediaRule` API behind flag Relates to #28438 This PR adds `CSSCustomMediaRule` API. Ref: * mozilla-firefox/firefox@f289eebba919#diff-5344d883f252f0d0fcde1443e722366428c6dec715f2dfa5a910d6d4fd088ce2 * https://bugzilla.mozilla.org/show_bug.cgi?id=1744292 --------- Co-authored-by: Claas Augner <495429+caugner@users.noreply.github.com>
| "chrome_android": "mirror", | ||
| "edge": "mirror", | ||
| "firefox": { | ||
| "version_added": "146", |
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Does this really work? I tested it and it didn't work.
data:text/html;charset=UTF-8,<!DOCTYPE html>
<style>
@custom-media --foo (width > 0px);
@media (--foo) {
div {
background: green;
width: 200px;
height: 200px;
}
}
</style>
<div>This should be a green background.</div>
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@emilio Given bug 2004653 (landed in Firefox 148), this feature actually doesn't work in Firefox 146. Will you backport it to Firefox 146?
Otherwise, all relevant MDN docs must be modified.
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@yisibl Since the feature is behind a flag, the fix probably won't be backported. If you like, you can open a PR correcting the version number, but once the feature ships in Firefox Stable, the flag entry will be removed anyhow.
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@caugner Okay, I recommend that for new features going forward, a demo must be provided for verification before merging pull requests.
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A demo doesn't prove the absence of major bugs. In general, when features are behind a flag, they are not stable, so bugs are expected.
Note that the majority of BCD features is covered by the MDN BCD Collector, which supports custom tests for cases like this, where a test case cannot be derived from the spec. However, we only run the MDN BCD Collector on Beta releases without any flags enabled.
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Summary
Firefox 146 added supports for
@custom-mediaat-rule.Feature information
Browsers support
Related issues
Last year I added this feature to BCD - #24338
But because no browsers implemented it yet, the feature was deleted - #25125
Now that Firefox implemented this, we can add it back to BCD.