CSS · Lesson 1 · 8 min

What is CSS?

Change colors, fonts, and spacing on your HTML.

You will learn

Link CSS to HTML with selectors
Change color and font-size
See live preview updates

CSS (Cascading Style Sheets) controls how HTML looks. You pick an element (like h1) and set rules (like color: blue).

Selector + property

h1 { color: navy; } means "make every h1 navy." Properties end with a semicolon.

Edit CSS — live preview below

HTML context (read-only)

<header>
  <h1>Starter Page</h1>
  <p>Edit the CSS to style this page.</p>
</header>
<main>
  <p class="highlight">This box can change color.</p>
  <button>Click me</button>
</main>

CSS

Live preview

Tip: Try background: #eef2ff on body.