SuperAPI AI Directory

modern-css

Frontend & websites

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Updated 10-15 20:11

About this skill

Modern CSS

Choose native CSS features that fit the requested behavior and supported browsers. The user's explicit instructions take precedence over this skill's guidelines. Preserve the project's framework, preprocessor, tokens, and styling conventions unless changing them is part of the request.

Resolve the styling problem

Use the affected markup/styles, desired appearance or interaction, and browser targets as input. Infer targets from project configuration when available. If missing support information changes the implementation, ask for it or state a conservative fallback.

Bundled support tables are dated research snapshots, not a current compatibility guarantee. Check MDN compatibility data or Web Platform Status for the particular feature when support matters.

Need Starting point
Rows and columns, or aligned nested tracks Grid / Subgrid
One-dimensional arrangement Flexbox
Layout based on a component's available space Container queries
Cascading overrides or specificity conflict Layers, scope, selector specificity
Themes and derived colors Custom properties, color functions, color-scheme
Motion, popovers, or scroll effects Feature-specific reference and fallback

Keep the result usable

  • Preserve layout and interaction in supported browsers. Use progressive enhancement or feature detection where a feature is unavailable.
  • Match cascade changes to the existing origin, importance, and layer ordering; adding a layer can change precedence.
  • Respect reduced-motion preferences and preserve focus/keyboard behavior when changing interactive components.
  • Use modern CSS as an option, not a mandate to remove JavaScript or rebuild working controls. Support and equivalent behavior determine whether a replacement fits.
  • Scope resets and stylesheet reorganization to the task; a component edit does not require a global reset.

Deliver the requested style change or explanation and verify affected layout/states when implementing. State unverified browser limitations rather than treating an example as proof of support.

References

Load only the relevant area, using its contents to find specific features.

Task Reference
Layers, scope, nesting, specificity CASCADE.md
Grid, Flexbox, containers, intrinsic sizing LAYOUT.md
Relational selectors, focus, pseudo-elements SELECTORS.md
Color spaces, palettes, dark mode COLOR.md
Custom properties, functions, design tokens TOKENS.md
Transitions, keyframes, entry/exit, view transitions ANIMATION.md
Scroll timelines, sticky states, carousels SCROLL.md
Dialogs, popovers, anchors, selects, field sizing COMPONENTS.md
Rendering performance, typography, writing modes PERFORMANCE.md
Compact syntax or feature-detection lookup CHEATSHEET.md