Web features explorer - at-rule()

Web features explorer

The at-rule() function, when used with @supports, checks if a CSS at-rule is supported. For example @supports at-rule(@starting-style) checks if the @starting-style at-rule is supported.

Browser support

Chrome 148 Released on 2026-05-05
Chrome Android 148 Released on 2026-05-05
Edge 148 Released on 2026-05-07
Firefox Not supported Position
Firefox for Android Not supported Position
Safari Not supported Position
Safari on iOS Not supported Position

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MDN documentation

No MDN documentation found. You can search for the feature on MDN. If you believe that MDN has no documentation about this feature, you can open an issue on MDN's GitHub repository.

Specifications

CSS Conditional Rules Module Level 5 (#typedef-supports-at-rule-fn), from Cascading Style Sheets (CSS) Working Group (W3C).

Web Platform Tests (WPT)

View the latest WPT test results for this feature

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