The CSS Selection

Analysis of real-world CSS usage across 100,000+ websites in 2026, examining stylesheet composition, at-rules (@media, @font-face, @keyframes, @supports, @container, @layer, @property), selectors (pseudo-classes like :where, :has, :is), specificity patterns, declarations, custom properties, color formats, and vendor prefixes. Key findings include 93% adoption of @media queries, 90% adoption of :where pseudo-class, 41% adoption of :has selector, and widespread use of hex color formats. The report establishes baseline metrics for tracking CSS evolution in future years.