CSS Tutorial

The language for styling web pages.

Chapter Quiz Exercises
Course Topics
CSS Introduction CSS Syntax CSS Selectors CSS Colors CSS Backgrounds CSS Borders CSS Margins CSS Padding CSS Box Model CSS Text CSS Fonts CSS Display CSS Position CSS Flexbox CSS Grid CSS Transitions CSS Animations CSS Media Queries CSS Variables CSS Gradients CSS Shadows CSS 2D Transforms CSS 3D Transforms CSS Pseudo-classes CSS Pseudo-elements CSS Float CSS Overflow CSS Z-index CSS Opacity CSS Buttons

CSS Variables

CSS Variables (Custom Properties)

CSS variables (also called custom properties) allow you to store values that can be reused throughout your stylesheet. They are defined with -- prefix and accessed with var().

Syntax:

:root { --primary: #1572B6; }
.element { color: var(--primary); }

Benefits:

  • Reusable values across the stylesheet
  • Easy to update (change one place = changes everywhere)
  • Can be changed with JavaScript
  • Supports theming (light/dark mode)

Try It Yourself

Edit the code below and click Run to see the result live.

Source Code
Result
Topics
CSS Introduction CSS Syntax CSS Selectors CSS Colors CSS Backgrounds CSS Borders CSS Margins CSS Padding CSS Box Model CSS Text CSS Fonts CSS Display CSS Position CSS Flexbox CSS Grid CSS Transitions CSS Animations CSS Media Queries CSS Variables CSS Gradients CSS Shadows CSS 2D Transforms CSS 3D Transforms CSS Pseudo-classes CSS Pseudo-elements CSS Float CSS Overflow CSS Z-index CSS Opacity CSS Buttons