The list of supported CSS @-rules is growing quite large, and it's very easy to miss a typo.

This rule checks each @-rule name to make sure that it is a known CSS @-rule. All vendor-prefixed @-rules are ignored because vendors may add in their own @-rules at any point in time.

Noncompliant Code Example

@abc { /* Noncompliant: 'abc' isn't a known @-rule */
  color: red;
}

Compliant Solution

@import url("styles.css"); /* Compliant: 'import' is a known @-rule */

@-moz-vendoratrule {} /* Compliant: '-moz-vendoratrule is a vendor @-rule */

List of Known @-rules