Disallow vendor prefixes for at-rules.
@-webkit-keyframes { 0% { top: 0; } } /** ↑ * This prefix */
true
The following patterns are considered violations:
@-webkit-keyframes { 0% { top: 0; } }
@-ms-viewport { orientation: landscape; }
The following patterns are not considered violations:
@keyframes { 0% { top: 0; } }
@viewport { orientation: landscape; }