Color Theory, Harmonic Palettes, and Web Accessibility (WCAG 2.1) Guide
Design beautiful, accessible color palettes for websites, brand identities, and mobile UI/UX layouts. Master classical color harmony schemes and contrast benchmarks to ensure readability for everyone.
The 4 Primary Color Harmony Systems
1. Complementary Harmonies
Positioned exactly 180° opposite on the 360° color wheel (such as Royal Blue and Vibrant Amber). Creates powerful visual contrast tailored for call-to-action (CTA) buttons and key metrics.
2. Analogous Harmonies
Adjacent colors spaced 30° to 60° apart (such as Forest Green, Teal, and Navy). Imparts serene, cohesive nature-inspired branding palettes.
3. Triadic Palettes
Three tones spaced 120° apart forming an equilateral triangle. Delivers vibrant, balanced color relationships popular in games, modern SaaS, and editorial designs.
4. Monochromatic Shades
Variations in saturation and lightness originating from a single base hue. Forms the foundation of modern minimalist clean UI designs.
WCAG 2.1 Contrast Ratio Standards
| WCAG Standard | Body Text (< 18pt) | Large Text (≥ 18pt or 14pt Bold) |
|---|---|---|
| Level AA (Legal Requirement) | Minimum 4.5:1 ratio | Minimum 3.0:1 ratio |
| Level AAA (Enhanced Accessibility) | Minimum 7.0:1 ratio | Minimum 4.5:1 ratio |
Color Models Explained: HEX, RGB, and HSL
- HEX (#RRGGBB): Base-16 hexadecimal alphanumeric codes used ubiquitously across HTML markup and CSS style sheets.
- RGB (rgb(R, G, B)): Standard additive color space representing red, green, and blue values from 0 to 255.
- HSL (hsl(H, S%, L%)): Hue (0–360°), Saturation (0–100%), and Lightness (0–100%). Ideal for generating programmatic dark and light UI component themes.
Frequently Asked Questions
- How do I export my palette to Figma or CSS?
- Click directly on any generated swatch to copy its HEX value to your clipboard, allowing immediate pasting into CSS custom properties or design token files.
- What is the 60-30-10 UI design rule?
- A classic design ratio: 60% dominant neutral background tone, 30% secondary structural color (cards, sidebars), and 10% high-contrast accent color for interactive CTAs.