How to use the CSS Cascade Layers Reviewer agent skill

What does the cascade-layers skill make the agent do?

Specificity conflicts are a common source of CSS bugs in large codebases. Developers often reach for !important, deeply nested selectors or inline styles to win those conflicts, which makes the stylesheet hard to maintain. The skill moves control of cascade order from selector specificity to an explicit layer order declared with @layer.

When the skill is active, the agent checks whether the CSS uses cascade layers and whether the layer order is declared. It looks for !important declarations, selectors with more than two class selectors, and inline styles used to override component styles. It can then recommend or write an @layer order for reset, base, components and utilities, and help move existing styles into those layers.

• Styles in later layers win over earlier layers, regardless of selector specificity or import order.
• Third-party and reset styles belong in early layers so your own styles override them.
• Unlayered styles have the highest priority, so you can migrate gradually.
• The skill is guidance for a CSS codebase, not a standalone tool.

How do you install the cascade-layers skill?

The skill is distributed as a ZIP file from this page. Download it, then unzip it into one of two places: your personal skills folder at ~/.claude/skills/, or a project's .claude/skills/ folder if you want the skill to apply only to that project.

If you use the Claude apps instead, you can upload the skill under Settings → Capabilities → Skills.

• Personal install: unzip into ~/.claude/skills/
• Project install: unzip into the project's .claude/skills/ folder
• Claude apps: upload under Settings → Capabilities → Skills

How do you trigger the skill with a natural request?

You do not need a special command. The skill's description says it applies when you are reviewing a CSS architecture for specificity issues, setting up a design system, or migrating a large codebase from utility-first to a layered architecture. Describe your situation in those terms and the agent can pick the skill up.

Be specific about your files and goals. Mention the stylesheet, the symptom (for example, a component that keeps losing to another rule) and what you want back (a review, a layer order, or a migration plan).

• Review my CSS for specificity conflicts and tell me where !important is hiding the real problem.
• Set up an explicit @layer order for our design system with reset, base, components and utilities.
• Help me migrate this utility-first stylesheet to a layered architecture without breaking the current look.

What does a typical review look like?

A useful review lists each problem with its location and a suggested fix. For example, it might point to a selector with several nested classes, a !important that exists only to beat a component rule, or an inline style that overrides a component. It can then propose where each style should live in the layer stack.

The skill's own guidance says to declare the layer stack at the top of your main CSS file so the order holds regardless of import sequence. Treat the output as a proposal and test it in the browsers your project supports.

What does the skill need, and what should you watch for?

The skill lists no required tools, does not run scripts and does not use the network. It works on the CSS you give it.

The skill's files do not cover browser compatibility. Cascade layers may not behave as expected in browsers or build setups that do not support them, so check your targets before relying on the layered output. For small projects with little CSS, the setup cost may outweigh the benefit.

• Requirements: none listed
• Runs scripts: no
• Uses network: no
• Compatibility: not covered by the skill's files; verify your target browsers and build setup

What tips help you get better results?

Give the agent the real stylesheet or the relevant files rather than a description. Ask for changes in small batches, such as one component or one layer at a time, so you can check the visual result after each step.

Keep unlayered styles in mind. They have the highest priority, so a stray unlayered rule can override your whole layer stack. Migrate gradually and review the result before removing old overrides.

• Paste or point to the actual CSS, not a summary.
• Migrate one component or layer at a time.
• Look for unlayered rules that could override the new stack.
• Compare visual output before and after each change.