Skip to main content
FreeToolkit .ai

CSS Variable Generator Generate CSS custom properties (variables) for colors, spacing, and typography.

CSS Variable Generator illustration
🎨

CSS Variable Generator

Generate CSS custom properties (variables) for colors, spacing, and typography.

1

Define variables

Add CSS custom properties with names and values, or use a preset theme.

2

Preview the theme

See your variables applied to a sample card with a button.

3

Copy the CSS

Copy the :root declaration with all your custom properties.

Loading tool...

What Is CSS Variable Generator?

The CSS Variable Generator creates custom properties (:root variables) for building consistent, maintainable design systems. CSS custom properties (also called CSS variables) are reusable values defined with -- prefix and accessed with the var() function. This tool lets you create, edit, and manage a set of variables for colors, spacing, typography, and any other CSS values. Color variables include integrated color pickers for easy visual selection. Preset themes (Dark Theme and Pastel) provide ready-made variable sets for common design patterns. A live preview shows your variables applied to a sample card component so you can see how the values work together. The output is a clean :root declaration block ready to paste at the top of your stylesheet.

Why Use CSS Variable Generator?

  • Visual color pickers integrated with variable editing
  • Theme presets for quick starting points
  • Live preview showing variables applied to a sample component
  • Add, edit, and remove variables with an intuitive interface

Common Use Cases

Design System Tokens

Create design tokens as CSS variables for consistent theming.

Theme Switching

Define variable sets for light and dark themes with easy switching.

Brand Customization

Set up brand colors and typography as reusable CSS variables.

Component Styling

Create component-level variables for configurable, reusable components.

Technical Guide

CSS custom properties are defined with -- prefix in a selector scope (typically :root for global availability): :root { --color-primary: #667eea; }. They are accessed with var(): color: var(--color-primary). Variables cascade and inherit like other CSS properties—defining them in :root makes them available everywhere. They can be overridden in any selector scope, enabling theming: .dark-theme { --color-primary: #90cdf4; }. Variables can reference other variables: --color-hover: var(--color-primary). For theming, define all variables in :root and override in theme classes. JavaScript can read and set variables: document.documentElement.style.setProperty('--color-primary', '#000'). Unlike preprocessor variables (Sass, Less), CSS custom properties are dynamic and can be changed at runtime. They are supported in all modern browsers.

Tips & Best Practices

  • 1
    Use semantic names (--color-primary) instead of descriptive ones (--blue-500)
  • 2
    Define all variables in :root and override in theme classes
  • 3
    Group related variables with consistent naming conventions
  • 4
    Use var() with fallback values: var(--color, #000) for robustness

Related Tools

CSS Gradient Generator - free online tool

CSS Gradient Generator

Create beautiful linear, radial, and conic CSS gradients with multiple color stops and angle control.

🎨 CSS & Design
Tailwind Config Generator - free online tool

Tailwind Config Generator

Generate Tailwind CSS configuration files with custom colors, fonts, and breakpoints.

🎨 CSS & Design
Typography Scale Generator - free online tool

Typography Scale Generator

Generate a modular typographic scale with customizable base size, ratio, and units.

🎨 CSS & Design
Spacing Scale Generator - free online tool

Spacing Scale Generator

Generate a consistent spacing scale system with customizable base unit and multipliers.

🎨 CSS & Design

Frequently Asked Questions

Q What are CSS custom properties?
CSS custom properties (variables) are reusable values defined with -- prefix, accessed with var(), that cascade and inherit like other CSS.
Q Can I use variables for any CSS value?
Yes, CSS variables can hold any valid CSS value: colors, sizes, font names, even complex values like shadows.
Q Are CSS variables supported in all browsers?
Yes, CSS custom properties are supported in all modern browsers. IE11 does not support them.
Q Can I change CSS variables with JavaScript?
Yes, use element.style.setProperty('--var-name', 'value') to change variables dynamically.
Q How are CSS variables different from Sass variables?
CSS variables are dynamic and can be changed at runtime. Sass variables are compiled at build time and cannot be changed in the browser.

About This Tool

CSS Variable Generator is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.