demo · v143

@supports for at-rules

Pick an at-rule. The page asks CSS.supports("at-rule(@x)") in your browser right now and shows the answer. A grid of common at-rules probes them all at once.

try an at-rule

Pick one and click Check.

battery: every common at-rule, live

the call

// New in v143: the at-rule() function inside @supports
@supports at-rule(@scope) {
  .scoped-thing { color: rebeccapurple; }
}

// And in JS
const ok = CSS.supports("at-rule(@scope)");

see also