HTML & Web Guide

1. Why Semantic HTML Matters

Using header, main, article, section, and nav improves structure for both users and crawlers.

• Better screen-reader navigation.
• Clearer content hierarchy for search engines.
• Lower maintenance cost over time.

2. CSS Architecture and Scale

Large projects benefit from consistent naming, reusable components, and design tokens (color, spacing, radius, typography).

3. Core Web Vitals and Speed

• LCP: Fast rendering of primary content.
• CLS: Stable layout with minimal shifts.
• INP: Responsive interactions.

Image optimization, script discipline, and critical CSS handling strongly impact these metrics.

4. Technical SEO Basics

• Precise title and meta description.
• Canonical + hreflang consistency.
• Sitemap and clean URL strategy.
• Proper heading hierarchy (H1-H2-H3).

5. Accessibility (a11y) Checklist

• Sufficient color contrast.
• Correctly labeled form controls.
• Keyboard navigation support.
• Meaningful alt text and aria usage.

6. Responsive Design Principles

Mobile-first layout, fluid grids, practical breakpoints, and touch-friendly controls create consistent UX across devices.

7. Pre-Launch Quality Flow

Performance audit → SEO metadata check → accessibility scan → broken-link test → real-device verification.