HTML

Document structure (doctype, html/head/body)

Semantic tags (main/nav/section/article)

Headings hierarchy (h1–h6)

Lists, tables basics

Links and navigation patterns

Inputs types and constraints

Labels, fieldsets, accessibility basics

Native validation basics

File inputs basics

Form UX patterns overview

Images: srcset/sizes basics

Picture element overview

Audio/video basics

iframes and embeds overview

Performance considerations overview

Keyboard navigation basics

Focus management basics

ARIA overview (when needed)

Alt text and captions

Common a11y pitfalls checklist

Build 3-page semantic layout

Create a complex form

Make a11y review with Lighthouse

SEO-friendly markup checklist

Mini project: blog post template