# Embedded Or Inline CSS

> Use when reviewing stylesheets, component styles, and responsive behavior related to Avoid embedded and inline CSS. Check the rendered layout across breakpoints and interaction states before proposing a fix.

- Skill: `thedaviddias/embedded-or-inline-css` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add thedaviddias/embedded-or-inline-css`
- Raw SKILL.md: https://api.skillmd.com/api/skills/thedaviddias/embedded-or-inline-css/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: thedaviddias (https://skillmd.com/u/thedaviddias)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/thedaviddias/embedded-or-inline-css

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# Avoid embedded and inline CSS

Inline CSS cannot be cached separately, increases HTML payload, breaks separation of concerns, and is harder to maintain in large codebases.

## Quick Reference

- Move inline styles to external CSS files or CSS-in-JS
- Exception: critical CSS should be inlined for performance
- Exception: dynamic values (CSS custom properties) can be inline
- Inline CSS breaks caching and increases HTML size

## Check

Verify that inline CSS and embedded styles are avoided except for valid use cases like critical CSS, dynamic styles, or performance optimization.

## Fix

Move inline and embedded CSS to external stylesheets, keeping only critical above-the-fold CSS inline for performance optimization.

## Explain

Explain why external CSS is preferred for maintainability, caching, and separation of concerns, with exceptions for critical CSS and dynamic styles.

## Code Review

Review stylesheets, component styles, and responsive states related to Avoid embedded and inline CSS. Flag exact selectors, declarations, or breakpoints that violate the rule in the rendered UI.

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For full implementation details, code examples, and framework-specific guidance,
see `references/rule.md`.

Rule page: https://frontendchecklist.io/en/rules/css/embedded-or-inline-css