modern-css

Proactively apply when creating design systems, component libraries, or any frontend application. Triggers on CSS Grid, Subgrid, Flexbox, Container Queries, :has(), @layer, @scope, CSS nesting, @property, @function, if(), oklch, color-mix, light-dark, relative color, @starting-style, scroll-driven animations, view transitions, anchor positioning, popover, customizable select, content-visibility, logical properties, text-wrap, interpolate-size, clamp, field-sizing, modern CSS, CSS architecture, responsive design, dark mode, theming, design tokens, cascade layers. Use when writing CSS for any web project, choosing layout approaches, building responsive components, implementing dark mode or theming, creating animations or transitions, styling form elements, or modernizing legacy stylesheets. Modern CSS features and best practices for building interfaces with pure native CSS.