Web30 min · Lesson 1 of 4

Semantic HTML5 & Modern CSS Layouts

Master the structure of the web. Semantic tags, Flexbox vs Grid, and CSS Variable architecture.

Semantic Foundations

HTML is the skeleton of your application. Using semantic tags like <main>, <article>, and <section> isn't just for SEO — it's for accessibility (A11y) and machine readability.

Modern Layout Engine

Modern CSS has moved beyond floats. We use Flexbox for 1D alignment and CSS Grid for 2D layouts. By combining these with CSS Custom Properties (variables), you create maintainable design systems.