CSS Variables for Theming
Create a token-based theme system using CSS custom properties that swap between light and dark values.
Theming Architecture Overview
CSS custom properties are the foundation of modern CSS theming. They act as a live token layer that can be swapped at runtime — enabling dark mode, white-labeling, and user-controlled personalization.
Design Token Layers
A well-structured theme system has three layers:
- Primitive tokens: raw values (
--blue-500: #3b82f6) - Semantic tokens: meaning-based (
--color-primary: var(--blue-500)) - Component tokens: component-specific (
--button-bg: var(--color-primary))
All lessons in this course
- prefers-color-scheme Media Query
- CSS Variables for Theming
- color-scheme Property
- Automatic and Manual Dark Mode Toggle