modern-css
Skill60 starsChanged 2 months agoMITView on GitHub
Implement or debug CSS layouts, responsive styles, themes, and motion. Use when choosing native CSS features or replacing legacy styling with browser-compatible CSS; not for unrelated frontend logic.
10 other projects use a version of this.
Adopted by
Most recently taken up by
- caidanw/skillstheir own version, first seen Nov 8, 2026
- jeferson-sb/skillstheir own version, first seen Oct 13, 2026
- jeferson-sb/react-native-perf-skillstheir own version, first seen Oct 13, 2026
- gitkraken/vscode-gitlenstheir own version, first seen Oct 8, 2026
- IsaacBell/ai-marketing-toolkittheir own version, first seen Sep 12, 2026
- abdul977/muahib-skillstheir own version, first seen Aug 20, 2026
Other versions10 projects use a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 10
- gitkraken/vscode-gitlens★ 10ksame name
- pass-agent/loomkin★ 179same name
- caidanw/skills★ 11same name
- jorgegorka/master-of-puppets★ 4same name
- magarcia/skills★ 4same name
- jeferson-sb/react-native-perf-skills★ 3same name
- jeferson-sb/skills★ 3same name
- mikezupper/modern-css-skill★ 2same name
- abdul977/muahib-skills★ 0same name
- IsaacBell/ai-marketing-toolkit★ 0same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository10 other files it gives its agents.
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The file
We split this skill into the rules it gives an agent
2 rules. 0 are common, 2 are distinctive, and 0 are very specific to this project.
0
Common
Most of the 10 edited versions we read keep these.
2
Distinctive
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 12
Use the affected markup/styles, desired appearance or interaction, and browser targets as input.
- Distinctive: line 30
Use modern CSS as an option, not a mandate to remove JavaScript or rebuild working controls.
“Common” is measured: kept by at least 6 in 10 of the 10 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
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 |
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