Specify a blacklist of disallowed at-rules.
@keyframes name {} /** ↑ * At-rules like this */
array|string
: ["array", "of", "unprefixed", "at-rules"]|"at-rule"
Given:
["extend", "keyframes"]
The following patterns are considered violations:
a { @extend placeholder; }
@keyframes name { from { top: 10px; } to { top: 20px; } }
@-moz-keyframes name { from { top: 10px; } to { top: 20px; } }
The following patterns are not considered violations:
@import "path/to/file.css";