Web Platform Design Guidelines

Framework-agnostic rules for accessible, performant, responsive web interfaces. Based on WCAG 2.2, MDN Web Docs, and modern web platform APIs.

1. Accessibility / WCAG [CRITICAL]

Accessibility is not optional. Most rules in this section map to WCAG 2.2 success criteria at Level A or AA. A small number of best-practice rules (noted inline) target Level AAA or go beyond WCAG.

1.1 Use Semantic HTML Elements

Use elements for their intended purpose. Semantic structure provides free accessibility, SEO, and reader-mode support.