name: css-development
description: This skill should be used when working with CSS, creating components, styling elements, refactoring styles, or reviewing CSS code. Triggers on "CSS", "styles", "Tailwind", "dark mode", "component styling", "semantic class", "@apply", "stylesheet". Routes to specialized sub-skills for creation, validation, or refactoring.

CSS Development Skill

Overview

Comprehensive workflow for CSS development using Tailwind + semantic component patterns. This skill automatically routes you to the appropriate specialized workflow based on context.

This skill will invoke one of three sub-skills:

• css-development:create-component - Creating new CSS components
• css-development:validate - Reviewing existing CSS
• css-development:refactor - Transforming CSS to semantic patterns

When This Skill Applies

Claude Code will automatically load this skill when you:

• Create new CSS components or styles
• Review or validate existing CSS code
• Refactor inline styles or utility classes
• Work with component styling in any framework
• Need to add dark mode support
• Write CSS tests

CSS Development Patterns

All sub-skills follow these core patterns. Reference this section when working with CSS.

Core Principles

1. Semantic Naming - Use descriptive class names (.button-primary, .card-header) not utility names (.btn-blue, .card-hdr)
2. Tailwind Composition - Leverage Tailwind utilities via @apply directive
3. Dark Mode by Default - Include dark: variants for all colored/interactive elements
4. Composition Over Creation - Reuse existing classes before creating new ones
5. Test Coverage - Static CSS tests + component rendering tests
6. Documentation - Usage comments above each component class

Component Class Pattern

/* Button component - Primary action button with hover states
   Usage: <button className="button-primary">Click me</button> */
.button-primary {
  @apply bg-indigo-500 hover:bg-indigo-700 dark:bg-indigo-600 dark:hover:bg-indigo-800;
  @apply px-6 py-3 rounded-lg font-medium text-white;
  @apply transition-all duration-200 hover:-translate-y-0.5;
}

Key characteristics:

• Group related utilities logically (background, spacing, typography, transitions)
• Include hover/focus/active states
• Include dark mode variants using dark: prefix
• Use Tailwind's built-in scales (indigo-500, gray-800, etc.)

File Structure Convention

styles/
├── components.css      # All semantic component classes
└── __tests__/
    └── components.test.ts  # CSS and component tests

Markup Integration (Framework-Agnostic)

Works with React, Vue, Svelte, or vanilla HTML:

React:

const classes = `button-primary ${className}`.trim();
<button className={classes}>...</button>

Vanilla HTML:

<button class="button-primary custom-class">...</button>

Vue:

<button :class="['button-primary', customClass]">...</button>

Key principle: Apply semantic class + allow additional classes for customization.

Atomic Design Levels

• Atoms: Basic building blocks (.button, .input, .badge, .spinner)
• Molecules: Composed components (.card, .form-field, .empty-state)
• Organisms: Complex components (.page-layout, .session-card, .conversation-timeline)

Testing Pattern

Static CSS Tests:

it('should have button component classes', () => {
  const content = readFileSync('styles/components.css', 'utf-8');
  expect(content).toContain('.button-primary');
});

Component Rendering Tests:

it('applies semantic class and custom className', () => {
  render(<Button variant="primary" className="custom" />);
  expect(screen.getByRole('button')).toHaveClass('button-primary', 'custom');
});

Workflow: Context Detection and Routing

When this skill is invoked, follow these steps to route to the appropriate sub-skill:

Step 1: Analyze Context

Look at the user's request and recent conversation to determine intent:

Creating new components?

• Keywords: "create", "add", "new component", "build a", "make a"
• Files: Mention of components.css or new component names
• Intent: User wants to add new CSS

Validating existing CSS?

• Keywords: "review", "validate", "check", "audit", "look at"
• Files: Reference to existing CSS files or components
• Intent: User wants feedback on existing CSS

Refactoring CSS?

• Keywords: "refactor", "clean up", "extract", "improve", "convert"
• Code: Inline styles or utility classes in markup visible
• Intent: User wants to transform existing CSS patterns

Step 2: Choose Sub-Skill

Based on context analysis:

If creating: Use the Skill tool to invoke css-development:create-component

If validating: Use the Skill tool to invoke css-development:validate

If refactoring: Use the Skill tool to invoke css-development:refactor

If ambiguous: Ask the user using AskUserQuestion tool:

Question: "What would you like to do with CSS?"
Options:
  - "Create new component" (Guide creating new semantic CSS component classes)
  - "Validate existing CSS" (Review CSS against established patterns)
  - "Refactor CSS" (Transform inline/utility styles to semantic components)

Step 3: Invoke Sub-Skill

Use the Skill tool to invoke the chosen sub-skill:

Example:

I'm routing you to the create-component workflow.
[Invoke Skill tool with skill: "css-development:create-component"]

Step 4: Hand Off Control

Once the sub-skill is invoked, it takes over. The main skill's job is complete.

Important Notes

• Don't skip routing: Always analyze context and choose the right sub-skill
• Don't duplicate sub-skill logic: Let sub-skills handle their workflows
• Reference pattern documentation: Sub-skills will reference the patterns documented above
• User can invoke directly: User can call sub-skills directly (e.g., "use css-development:validate")