Bug 2060755 Comment 0 Edit History

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Original comment by
on 
Ship the `at-rule()` function for `@supports` by enabling `layout.css.supports.at-rule.enabled` for release builds.

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**Release Note Request (optional, but appreciated)**
[Why is this notable]: New CSS feature, parity with Chrome
[Affects Firefox for Android]: Yes
[Suggested wording]: Firefox now supports the [`at-rule()`](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/At-rules/@supports#at-rule) function for `@supports`. This allows authors to detect for browser support of specific at-rules, such as `@supports at-rule(@scope)`.
[Links (documentation, blog post, etc)]: 
- https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/At-rules/@supports#at-rule\
- https://www.bram.us/2026/03/15/at-rule/
Revision 1 by
on 
Ship the `at-rule()` function for `@supports` by enabling `layout.css.supports.at-rule.enabled` for release builds.

---

**Release Note Request (optional, but appreciated)**
[Why is this notable]: New CSS feature, parity with Chrome
[Affects Firefox for Android]: Yes
[Suggested wording]: Firefox now supports the [`at-rule()`](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/At-rules/@supports#at-rule) function for `@supports`. This allows authors to detect for browser support of specific at-rules, such as `@supports at-rule(@scope)`.
[Links (documentation, blog post, etc)]: 
- https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/At-rules/@supports#at-rule
- https://www.bram.us/2026/03/15/at-rule/

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