v148 · css · feature detection · covered on mdn
at-rule: CSS Feature Detection
Chrome 148 adds an at-rule() function to CSS @supports, enabling authors to test whether a browser supports a given CSS at-rule — such as @container, @layer, or @starting-style — without JavaScript or heuristic workarounds.
this feature is documented on MDN
MDN: @supports — at-rule()
MDN's @supports reference documents the at-rule() function — “This function checks if a browser supports the specified at-rule” — with its syntax and examples. gendn doesn't duplicate that here.
quick reference
| Chrome 148+ (desktop, Android, WebView) | Enabled by default |
|---|---|
| Firefox | No position |
| Safari | No position |
| Spec | CSS Conditional Rules Level 5 |
| ChromeStatus | 5110744177836032 — at-rule: CSS Feature Detection |