Summary The :root CSS pseudo-class matches the root element of a tree representing the document. Applied to HTML, :root represents the <html> element and is identical to the selector html, except that its specificity is higher. Specifications Specification Status Comment Selectors Level 4 Working Draft No change. Selectors Level 3 Recommendation Browser compatibility Desktop Mobile Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari Basic support 1 1.0 (1.7 or earlier) 9 9.5 1.0 Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Basic support ? ? ? ? ?