Definition
CSS Parser API defines CSSParserAtRule
[Exposed=Window]
interface CSSParserAtRule : CSSParserRule {
constructor(DOMString name, sequence<CSSToken> prelude, optional sequence<CSSParserRule>? body);
readonly attribute DOMString name;
readonly attribute FrozenArray<CSSParserValue> prelude;
readonly attribute FrozenArray<CSSParserRule>? body;
/* nullable to handle at-statements */
stringifier;
};