Quick Start Guide
Skip the theory for now. This guide gets you writing production-quality CSS immediately using the patterns from this curriculum.
What is CSS?
CSS (Cascading Style Sheets) is the standard language for controlling the visual presentation of web pages — the colors, layout, spacing, typography, animations, and responsive behavior that make the difference between a raw HTML document and a polished website.
How to Add CSS
There are multiple ways to add CSS to an HTML document. Choosing the right method depends on your project type, team size, and whether you have a build step. This page covers all methods with their real-world tradeoffs.
Syntax and Selectors
To style any element, you need to know two things: how to target it (the selector) and how to correctly write the rule (the syntax). This page covers every selector type and combination you'll use in real production CSS.
CSS Comments and Documentation
CSS comments are more than syntax — they are your documentation system, your team communication layer, and your AI context tool. Used strategically, they transform a CSS file from a list of rules into a self-explaining codebase.
Vendor Prefixes
Vendor prefixes were the browser's way of implementing experimental CSS before the spec was finalized. Most are now obsolete — but a small critical set are still required in 2026, especially for Safari compatibility.