Reference

Color Theory

Master color theory to create visually appealing, accessible, and effective digital interfaces.

Reference·Difficulty: Intermediate·10 chapters·Updated May 10, 2026

In this collection

About

Pick colors with intention. Make them readable. Build palettes that hold up across light mode, dark mode, and accessibility audits.

Contents

FileDescription
01-fundamentals.mdHow color works: light, perception, and basic terminology
02-color-models.mdRGB, HEX, HSL, and when to use each
03-color-wheel.mdThe wheel, primary/secondary/tertiary, warm vs cool
04-color-harmony.mdComplementary, analogous, triadic, and other schemes
05-color-psychology.mdEmotional impact, cultural meanings, brand associations
06-contrast-accessibility.mdWCAG, contrast ratios, and inclusive design
07-color-in-ui.mdApplying color to UI elements, hierarchy, and states
08-building-palettes.mdCreating cohesive color systems for projects
09-dark-mode.mdDesigning effective dark themes
10-tools-reference.mdTools and quick reference

Prerequisites

  • Basic familiarity with CSS (you know what color and background-color do)
  • Access to a design tool (Figma, Sketch) or browser dev tools

Quick Start

In a hurry? Read these three:

  1. 02-color-models.md for HSL, the most intuitive model
  2. 06-contrast-accessibility.md for accessibility essentials
  3. 08-building-palettes.md to build your first palette

Key Takeaways

After working through these files you can:

  • Pick colors with reasons, not vibes
  • Hit WCAG AA contrast every time
  • Build a complete palette (neutrals, primary, semantic) for a new project
  • Ship a dark mode that does not just invert the light one
  • Defend your color decisions in a review