Roadmap › HTML5 & CSS3 — Semantic Markup to Responsive Layouts › Module: Modern CSS and Frameworks
Lessons in this course (11)

11. Performance and SEO for HTML/CSS

AdvancedMediumLesson 11 of 11
  • Critical CSS inline / small CSS bundles; remove unused CSS (Tailwind does this automatically).
  • <script defer> or type="module"; avoid render-blocking third-party scripts.
  • Images: modern formats (WebP/AVIF), correct sizes, width/height attributes to prevent layout shift, loading="lazy" below the fold.
  • Fonts: font-display: swap, preload the main font, limit weights.
  • Core Web Vitals: LCP (largest content paint ≤ 2.5 s), INP (interaction to next paint ≤ 200 ms), CLS (layout shift ≤ 0.1).
  • SEO basics: unique <title> and meta description, one h1, semantic structure, descriptive link text, alt text, canonical URLs, Open Graph tags for sharing.