Inline critical CSS for faster rendering

SkillMedia

Lets your agent check stylesheets and responsive layouts to inline critical CSS for faster page rendering.

Available today. Use it from your connected AI after setup.

Connect ahel once, and every AI you use reads what you have installed.

Then ask your AI: use the Inline critical CSS for faster rendering skill

About this capability

Use when reviewing stylesheets, component styles, and responsive behavior related to Inline critical CSS for faster rendering. Check the rendered layout across breakpoints and interaction states before proposing a fix.

What this skill tells your AI

The instructions your AI receives, as published by thedaviddias/front-end-checklist in skills/css-critical/SKILL.md and read by ahel’s review.

Critical CSS eliminates render-blocking resources, enabling browsers to paint content immediately—directly improving LCP and FCP scores.

Quick Reference

  • Inline ~14KB of critical above-the-fold CSS in
  • Use tools: critical, critters, or Lighthouse to extract
  • Load remaining CSS asynchronously after page load
  • Automate in build process—don't manually maintain

Check

Analyze this page's CSS loading strategy to identify critical above-the-fold styles that should be inlined and non-critical styles that can be loaded asynchronously.

Fix

Extract and inline critical CSS for above-the-fold content, then load remaining CSS asynchronously to improve initial page render performance.

Explain

Explain how critical CSS improves Core Web Vitals by reducing render-blocking resources and enabling faster First Contentful Paint and Largest Contentful Paint.

Code Review

Review stylesheets, component styles, and responsive states related to Inline critical CSS for faster rendering. Flag exact selectors, declarations, or breakpoints that violate the rule in the rendered UI.


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

Rule page: https://frontendchecklist.io/en/rules/css/css-critical

Signals

GitHub stars
74k
Forks
7k
Last commit
Aug 2026
Advanced
Catalog kind
skill
Gateway key
css-critical
Source
github.com/thedaviddias/front-end-checklist