material-theme-builder

name	material-theme-builder
description	Generate Material Design 3 color themes programmatically from a source color using @material/material-color-utilities, the same engine that powers the Material Theme Builder. Use this when the user asks to generate an M3 color palette, create a custom theme from a brand color, or export M3 tokens to CSS, JSON, or framework configs.
license	Apache-2.0

Material Theme Builder

Overview

Generate complete Material Design 3 color themes programmatically from any source color. This skill uses @material/material-color-utilities — the same color algorithm library that powers Google's Material Theme Builder — to produce accessible light/dark palettes, tonal ranges, and design tokens ready for CSS, JSON, or any framework.

Keywords: Material Theme Builder, color generation, dynamic color, theme export, @material/material-color-utilities, HCT, tonal palette, source color, brand color, CSS tokens, JSON export

When to Use

• "Generate an M3 theme from my brand color"
• "Create M3 color tokens from #FF9800"
• "Export M3 palette as CSS custom properties"
• Creating a new M3 project and need a complete color token set
• Converting a hex brand color into a full M3 palette
• Generating both light and dark theme tokens programmatically

How It Works

Material Color Utilities uses the HCT color space (Hue, Chroma, Tone) — a perceptually uniform color model built on CAM16 and L* — to generate five tonal palettes from a single source color:

1. Primary — derived from the source color's hue
2. Secondary — desaturated variant of the source hue
3. Tertiary — complementary hue for contrast
4. Neutral — very low chroma for surfaces and backgrounds
5. Neutral Variant — slightly chromatic neutral for outlines

Each palette contains tones 0–100. Specific tones are mapped to semantic color roles (e.g., primary = tone 40 in light, tone 80 in dark).

Install

npm install @material/material-color-utilities

Generate a Theme

Use the generate-theme.mjs script in this skill's directory:

node generate-theme.mjs "#FF9800"                     # CSS output (default tonal-spot)
node generate-theme.mjs "#FF9800" --json               # JSON output
node generate-theme.mjs "#FF9800" --scheme expressive   # Expressive scheme variant

Available Scheme Variants

The --scheme flag selects from 9 dynamic color strategies defined in material-color-utilities:

Scheme	Description
tonal-spot	Default — balanced, versatile (used by Android Material You)
content	Colors derived with fidelity to the source, good for photo-based themes
expressive	Intentionally detached from source for bold, playful palettes
fidelity	High fidelity to source hue, chroma-capped for accessibility
fruit-salad	Vibrant, playful secondary and tertiary from offset hues
monochrome	Achromatic — all palettes have zero chroma
neutral	Near-achromatic — very low chroma for subtle, muted themes
rainbow	Wide hue spread across primary, secondary, and tertiary
vibrant	Saturated, colorful variant of tonal-spot

Quick Start (Node.js)

import {
  argbFromHex,
  hexFromArgb,
  themeFromSourceColor,
} from "@material/material-color-utilities";

// Generate from any hex source color
const theme = themeFromSourceColor(argbFromHex("#FF9800"));

// Extract light scheme
const light = theme.schemes.light.toJSON();
for (const [role, argb] of Object.entries(light)) {
  console.log(`${role}: ${hexFromArgb(argb)}`);
}

Full Theme with Surface Containers

The base themeFromSourceColor provides core roles. Surface container tones are derived from the neutral palette at specific tones:

import {
  argbFromHex,
  hexFromArgb,
  themeFromSourceColor,
} from "@material/material-color-utilities";

const theme = themeFromSourceColor(argbFromHex("#FF9800"));
const neutral = theme.palettes.neutral;
const primary = theme.palettes.primary;
const secondary = theme.palettes.secondary;
const tertiary = theme.palettes.tertiary;

// Light surface containers (tone values per M3 spec)
const lightSurfaces = {
  surface:                 neutral.tone(98),
  surfaceDim:              neutral.tone(87),
  surfaceBright:           neutral.tone(98),
  surfaceContainerLowest:  neutral.tone(100),
  surfaceContainerLow:     neutral.tone(96),
  surfaceContainer:        neutral.tone(94),
  surfaceContainerHigh:    neutral.tone(92),
  surfaceContainerHighest: neutral.tone(90),
};

// Dark surface containers
const darkSurfaces = {
  surface:                 neutral.tone(6),
  surfaceDim:              neutral.tone(6),
  surfaceBright:           neutral.tone(24),
  surfaceContainerLowest:  neutral.tone(4),
  surfaceContainerLow:     neutral.tone(10),
  surfaceContainer:        neutral.tone(12),
  surfaceContainerHigh:    neutral.tone(17),
  surfaceContainerHighest: neutral.tone(22),
};

// Fixed colors (consistent across light and dark)
const fixed = {
  primaryFixed:              primary.tone(90),
  onPrimaryFixed:            primary.tone(10),
  primaryFixedDim:           primary.tone(80),
  onPrimaryFixedVariant:     primary.tone(30),
  secondaryFixed:            secondary.tone(90),
  onSecondaryFixed:          secondary.tone(10),
  secondaryFixedDim:         secondary.tone(80),
  onSecondaryFixedVariant:   secondary.tone(30),
  tertiaryFixed:             tertiary.tone(90),
  onTertiaryFixed:           tertiary.tone(10),
  tertiaryFixedDim:          tertiary.tone(80),
  onTertiaryFixedVariant:    tertiary.tone(30),
};

Export Formats

CSS Custom Properties

function schemeToCss(scheme, selector = ":root") {
  const entries = Object.entries(scheme.toJSON());
  const props = entries
    .map(([key, argb]) => {
      const token = key.replace(/([A-Z])/g, "-$1").toLowerCase();
      return `  --md-sys-color-${token}: ${hexFromArgb(argb)};`;
    })
    .join("\n");
  return `${selector} {\n${props}\n}`;
}

console.log(schemeToCss(theme.schemes.light));
console.log(schemeToCss(theme.schemes.dark, '[data-theme="dark"]'));

JSON

function schemeToJson(scheme) {
  const result = {};
  for (const [key, argb] of Object.entries(scheme.toJSON())) {
    result[key] = hexFromArgb(argb);
  }
  return result;
}

const output = {
  source: "#FF9800",
  light: schemeToJson(theme.schemes.light),
  dark: schemeToJson(theme.schemes.dark),
};
console.log(JSON.stringify(output, null, 2));

Apply to DOM

import { applyTheme } from "@material/material-color-utilities";

const systemDark = window.matchMedia("(prefers-color-scheme: dark)").matches;
applyTheme(theme, { target: document.body, dark: systemDark });

Custom Colors (Extended Palette)

Add brand-specific colors that harmonize with the generated theme:

const theme = themeFromSourceColor(argbFromHex("#FF9800"), [
  {
    name: "brand-green",
    value: argbFromHex("#4CAF50"),
    blend: true, // harmonize with the source color
  },
  {
    name: "warning",
    value: argbFromHex("#FFC107"),
    blend: false, // keep exact hue
  },
]);

// Access custom colors
for (const custom of theme.customColors) {
  console.log(`${custom.color.name}:`);
  console.log(`  light: ${hexFromArgb(custom.light.color)}`);
  console.log(`  dark:  ${hexFromArgb(custom.dark.color)}`);
}

Platform Libraries

Platform	Package
TypeScript	@material/material-color-utilities (npm)
Dart	material_color_utilities (pub.dev)
Java/Kotlin	Built into MDC-Android
Swift	Source in material-color-utilities repo
C++	Source in material-color-utilities repo

Checklist

• Source color chosen (brand primary or user-provided hex)
• @material/material-color-utilities installed
• Light and dark schemes generated via themeFromSourceColor
• Surface container tokens derived from neutral palette tones
• Fixed accent colors derived from primary/secondary/tertiary palette tones
• Tokens exported in the target format (CSS, JSON, or framework config)
• Custom/extended colors added if needed (with harmonization)
• Both light and dark themes tested for WCAG contrast compliance

Resources

• Material Theme Builder (web): https://material-foundation.github.io/material-theme-builder/
• Material Theme Builder (repo): https://github.com/material-foundation/material-theme-builder
• Material Color Utilities: https://github.com/material-foundation/material-color-utilities
• Official M3 CSS tokens (baseline): https://github.com/material-foundation/material-tokens
• npm: https://www.npmjs.com/package/@material/material-color-utilities
• M3 design tokens overview: https://m3.material.io/foundations/design-tokens/overview
• M3 color system: https://m3.material.io/styles/color/overview
• HCT color space: https://material.io/blog/science-of-color-design