ladybird/Userland/Libraries/LibWeb/CSS/CSS.idl

// https://www.w3.org/TR/cssom-1/#namespacedef-css
[Exposed=Window]
namespace CSS {
    CSSOMString escape(CSSOMString ident);

    boolean supports(CSSOMString property, CSSOMString value);
    boolean supports(CSSOMString conditionText);
};