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CSS Architecture

Organize CSS using BEM, SMACSS, and CSS-in-JS patterns. Use when building scalable, maintainable styling systems with proper naming conventions.

BY aj-geddesUPDATED Oct 28, 2026
INTENDED FOR✳Claude Code>_Codex↗Cursor◎ChatGPT✦GeminiInstall in a listed agent.

instructions.md

---
name: css-architecture-91fe44eb14a9
description: >
  Organize CSS using BEM, SMACSS, and CSS-in-JS patterns. Use when building
  scalable, maintainable styling systems with proper naming conventions.
---

# CSS Architecture

## Table of Contents

- [Overview](#overview)
- [When to Use](#when-to-use)
- [Quick Start](#quick-start)
- [Reference Guides](#reference-guides)
- [Best Practices](#best-practices)

## Overview

Build maintainable CSS systems using methodologies like BEM (Block Element Modifier), SMACSS, and CSS-in-JS patterns with proper organization and conventions.

## When to Use

- Large-scale stylesheets
- Component-based styling
- Design system development
- Multiple team collaboration
- CSS scalability and reusability

## Quick Start

Minimal working example:

```css
/* Block - standalone component */
.button {
  display: inline-block;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 16px;
  transition: all 0.3s ease;
}

/* Element - component part */
.button__icon {
  margin-right: 8px;
  vertical-align: middle;
}

/* Modifier - variant */
.button--primary {
  background-color: #007bff;
  color: white;
}

.button--primary:hover {
  background-color: #0056b3;
// ... (see reference guides for full implementation)
```

## Reference Guides

Detailed implementations in the `references/` directory:

| Guide | Contents |
|---|---|
| [BEM (Block Element Modifier) Pattern](references/bem-block-element-modifier-pattern.md) | BEM (Block Element Modifier) Pattern |
| [SMACSS (Scalable and Modular Architecture for CSS)](references/smacss-scalable-and-modular-architecture-for-css.md) | SMACSS (Scalable and Modular Architecture for CSS) |
| [CSS-in-JS with Styled Components](references/css-in-js-with-styled-components.md) | CSS-in-JS with Styled Components |
| [CSS Variables (Custom Properties)](references/css-variables-custom-properties.md) | CSS Variables (Custom Properties) |
| [Utility-First CSS (Tailwind Pattern)](references/utility-first-css-tailwind-pattern.md) | Utility-First CSS (Tailwind Pattern) |

## Best Practices

### ✅ DO

- Follow established patterns and conventions
- Write clean, maintainable code
- Add appropriate documentation
- Test thoroughly before deploying

### ❌ DON'T

- Skip testing or validation
- Ignore error handling
- Hard-code configuration values
COMPATIBILITY & REFERENCES

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Imported from the listed AgentSkill.sh category. Complete supplied package files and notices are retained. Required external tools and credentials are not installed. No bundled code was executed during import. Individual agent task behavior has not been tested.