If your coding assistant struggles with CSS, this is exactly why we created this skill.

CSS Pro-Tips gives your agent the CSS superpowers it needs: a clear policy for tokens, cascade control, static CSS, component-first layouts, accessibility, performance, and fallbacks that actually work.

Install | What your agent gets | Use it | Maintain it

Install

The fastest path works for 75+ coding agents. skills detects the agents you have installed and copies the skill into each one:

npx skills add PyModel/css-pro-tips            # this project
npx skills add PyModel/css-pro-tips -g         # every project (global)
npx skills add PyModel/css-pro-tips -g -a claude-code -a codex   # specific agents

Or install from npm and copy it yourself:

npm install css-pro-tips
SKILL_DIR=~/.claude/skills/css-protips          # pick your agent's path below
mkdir -p "$SKILL_DIR"
cp -R node_modules/css-pro-tips/SKILL.md node_modules/css-pro-tips/references "$SKILL_DIR"/

Always copy both SKILL.md and references/. SKILL.md is a small router that is loaded on every activation; it links to references/*.md, which the agent reads only when a task needs them. To pick up updates automatically, symlink the package instead of copying it. Remove any copied directory first, or the link is created inside it:

rm -rf "$SKILL_DIR" && ln -s "$(pwd)/node_modules/css-pro-tips" "$SKILL_DIR"

Where each agent looks

Install into a css-protips/ folder under one of these directories. Project paths can be committed so your team shares the skill.

Agent	npx skills -a	Project	Global
Claude Code	claude-code	.claude/skills/	~/.claude/skills/
OpenAI Codex	codex	.agents/skills/	~/.codex/skills/
Cursor	cursor	.agents/skills/	~/.cursor/skills/
GitHub Copilot	github-copilot	.agents/skills/	~/.copilot/skills/
Gemini CLI	gemini-cli	.agents/skills/	~/.gemini/skills/
Google Antigravity	antigravity	.agents/skills/	~/.gemini/antigravity/skills/
OpenCode	opencode	.agents/skills/	~/.config/opencode/skills/
Pi	pi	.pi/skills/	~/.pi/agent/skills/
Pythinker Code	—	.pythinker-code/skills/ or .agents/skills/	~/.pythinker-code/skills/ or ~/.agents/skills/
Kiro CLI	kiro-cli	.kiro/skills/	~/.kiro/skills/
Windsurf	windsurf	.windsurf/skills/	~/.codeium/windsurf/skills/
Cline, Warp, Zed, Kimi Code CLI	cline, warp, zed, kimi-code-cli	.agents/skills/	~/.agents/skills/
Amp, Replit	amp, replit	.agents/skills/	~/.config/agents/skills/
Roo Code	roo	.roo/skills/	~/.roo/skills/
Kilo Code	kilo	.agents/skills/	~/.kilo/skills/
Continue	continue	.continue/skills/	~/.continue/skills/
Goose	goose	.goose/skills/	~/.config/goose/skills/
Factory Droid	droid	.agents/skills/	~/.factory/skills/
Qwen Code	qwen-code	.qwen/skills/	~/.qwen/skills/
Grok Build	grok	.grok/skills/	~/.grok/skills/
Devin for Terminal	devin	.devin/skills/	~/.config/devin/skills/
JetBrains Junie	junie	.junie/skills/	~/.junie/skills/
Augment	augment	.augment/skills/	~/.augment/skills/
OpenHands	openhands	.openhands/skills/	~/.openhands/skills/
Trae	trae	.trae/skills/	~/.trae/skills/
Crush	crush	.crush/skills/	~/.config/crush/skills/
AiderDesk	aider-desk	.aider-desk/skills/	~/.aider-desk/skills/

Paths come from the skills supported-agents table, which lists the rest of the 75+ agents. Pythinker Code's paths come from its skill loader. Kiro custom agents also need "resources": ["skill://.kiro/skills/**/SKILL.md"] in .kiro/agents/<agent>.json.

Aider has no skill discovery. Load the router as a read-only conventions file, and add the reference files a task needs:

aider --read node_modules/css-pro-tips/SKILL.md \
      --read node_modules/css-pro-tips/references/layout-containers.md

To load it every session, add read: [node_modules/css-pro-tips/SKILL.md] to .aider.conf.yml.

What your agent gets

The skill starts with an execution contract: activation and negative triggers, validated inputs, gated execution, acceptance criteria, and failure recovery. Review mode and no dependency changes are the defaults. It then supplies CSS decisions, implementation guidance, and compatibility evidence.

Decision	Guidance
Architecture	Semantic design tokens, CSS custom properties, cascade layers, component scope, CSS Modules, Tailwind v4, and when runtime CSS-in-JS has a real reason to exist
Layout	Grid, Flexbox, intrinsic sizing, aspect-ratio, container queries, container units, style queries, and viewport fallbacks
Typography	Unitless line height, bounded clamp() type, text-wrap, text-box, font loading, subsetting, and fallback metrics
Color	Semantic themes, oklch(), color-mix(), light-dark(), relative-color fallbacks, and forced-colors behavior
State	:focus-visible, :has(), native form state, :open, popovers, customizable select, and real ARIA/data state
Motion	Native transitions, semantic disclosures, optional Animate.css presets, cancellation-safe lifecycle guidance, no-motion/print baselines, View Transitions, and scroll-driven animation limits
Accessibility	Focus, contrast, forced colors, reduced transparency, zoom, reflow, keyboard behavior, and semantic HTML
Performance	Static output, CSS delivery, critical CSS, fonts, content-visibility, and profiling instead of selector folklore
Tooling	CSS Modules, Tailwind v4, Sass/Less relevance, PostCSS, Autoprefixer, Browserslist, and Stylelint

It also includes a generated compatibility quick reference. Widely available features can be normal production CSS for evergreen targets. Newly available features need a browser-floor check. Limited availability features are optional enhancements with a viable baseline first.

Use it

1. Install the skill with npx skills add or copy SKILL.md and references/ into your agent's skill directory.
2. Ask the agent to write, review, refactor, or modernize CSS.
3. The skill directs it to choose a policy and fallback before it chooses a feature, and to load only the references the task needs.

It follows the Agent Skills specification, so any client that reads a SKILL.md directory can use it.

Animate.css reference

The animation module references Animate.css without adding it as a package dependency. It covers the v4 class prefix, timing variables, single-owner imports, reduced-motion/print handling, cancellation and missing-CSS paths, production bundle checks, and migration/rollback.

The reference was reviewed on September 4, 2026 against the v4.1.1 source tag. That tag's license is MIT; the live website states a different license. Check the exact distributed artifact and the project's dependency policy before adopting it. This is a versioned reference, not a claim that 4.1.1 is the latest release.

Compatibility and evidence

• Package version: 2.0.1
• Last validation window: September 2026 (derived from the most recent claim reviewed_at in content/evidence.yml)
• Compatibility model: MDN Baseline
• Generated compatibility summary
• Generated evidence index
• Release history: CHANGELOG.md

Baseline reports browser support, not whether a rule is accessible, keyboard-usable, readable, or fast. The skill treats those checks as separate constraints.

Maintain it

SKILL.md is generated from the canonical files in content/. The repository keeps policy, capabilities, compatibility claims, sources, and concept modules separate so a source update does not turn into a manual edit across several tables.

npm run build
npm test
npm run pack:check

npm run build regenerates the SKILL.md router, references/, and the evidence index. npm test rejects stale generated output, invalid frontmatter, broken references, source-contract drift, release metadata drift, and unexpected package contents. It also checks the five-part execution contract, optional Animate.css guidance, versioned evidence, reduced-motion safeguards, and top-level vendor imports. GitHub Actions runs these checks with read-only repository permissions. The published npm package contains the router, its generated references, and normal package metadata; a word/heading ceiling test keeps the always-loaded router small.

The September 2026 review records confirmed findings, verification scope, and remaining limitations. Browser-compatibility claims for motion references were refreshed in that review; adding animation references does not revalidate every browser claim.

CSS Pro-Tips is maintained by elkaix under the PyModel organization.

License

MIT © 2026 elkaix