CSS Feature Support Checker

Test CSS feature support on any browser - smart TVs, embedded devices, and non-standard environments.

Selectors & Scoping

Modern selector capabilities for precise element targeting and style isolation.

⏳ :has() Pseudo-Class
Select parent elements based on children state (parent selector).
selector(:has(> img))MDN
⏳ :is() Pseudo-Class
Match multiple selectors with forgiving syntax.
selector(:is(h1, h2, h3))MDN
⏳ :where() Pseudo-Class
Like :is() but with zero specificity for easier overrides.
selector(:where(h1, h2))MDN
⏳ :focus-visible
Style focus only when keyboard navigation is detected.
selector(:focus-visible)MDN
⏳ :focus-within
Style elements when they or descendants have focus.
selector(:focus-within)MDN
⏳ CSS Nesting
Nest selectors without preprocessors for better readability.
selector(& .nested)MDN