UI and design system glossary

The glossary provides clear, concise definitions for UI, UX, and design system terminology.

Each term is explained in plain language, with context and practical relevance — helping designers and developers align on meaning and intent.

This section is designed to grow into a comprehensive reference over time.

Terms
27 entries
Design tokens
Named design decisions (colors, typography, spacing, radius, shadows) exported into code-friendly formats like CSS variables, Tailwind config, or JSON.
What are design tokens?
Semantic color tokens
Tokens named by role (surface, text-muted, border, accent, danger) instead of raw hue, so the same names work across light and dark themes.
How semantic color tokens work
WCAG contrast ratio
A measurement of readability between foreground and background colors, expressed as a ratio from 1:1 to 21:1. Higher ratios mean better readability.
WCAG contrast guarantee
WCAG AA / AAA
Accessibility conformance targets. AA is the practical baseline for most product UIs (4.5:1 for normal text); AAA is stricter (7:1) and often constrains color choices significantly.
WCAG AA vs AAA for UI design
Semantic colors
State/meaning colors like success, warning, danger, and info. They are used consistently across components regardless of brand palette.
Color tokens vs CSS variables
Color tokens are the abstract, named design decisions; CSS variables are one way to implement them in code. A token can also export to Tailwind config or JSON without ever becoming a CSS variable.
CSS variables theme generator
HSL color model
A color model describing color as hue, saturation, and lightness. Easier for humans to reason about than RGB when generating consistent palettes or shade ramps.
OKLCH color model
A perceptually uniform color space (lightness, chroma, hue) where equal numeric steps look like equal visual steps. Useful for generating accessible shade ramps that don't shift unexpectedly in perceived brightness.
Color contrast formula
WCAG 2.x contrast is calculated from the relative luminance of two colors: (L1 + 0.05) / (L2 + 0.05), where L1 is the lighter color's luminance. The result is the contrast ratio used for AA/AAA checks.
Design system
A shared set of tokens, components, and patterns used across a product so teams build consistent, accessible UI without re-deciding the same details every time.
SaaS design system guide
Atomic design
A methodology that organizes UI into atoms (colors, type, spacing), molecules (small components), organisms (composed sections), templates, and pages.
Vibe
A high-level style preset that guides the generator’s choices (palette character, typography mood, density, and overall UI feel).
Direction
A controlled variation inside a Vibe that pushes the look in a specific art direction while staying recognizable and coherent.
Preset
A saved configuration you can reuse later (e.g. a palette + typography + settings snapshot).
Preview
A real UI layout used to validate that tokens work in context (surfaces, borders, typography hierarchy, component states), not just as swatches.
Theme templates
Export
The output you copy into a project: CSS variables, Tailwind theme extension, JSON tokens, or shadcn/ui-oriented variables. The goal is production usage without ChromUI running.
Exports hub
Design token JSON
A portable, framework-agnostic export format for tokens (often nested by category: color, typography, spacing) that other tools or build pipelines can consume.
Design tokens JSON export
Tailwind theme extension
Custom colors, spacing, or other values added to Tailwind's config under `theme.extend`, so generated tokens become usable utility classes.
Tailwind theme export
shadcn/ui theme variables
CSS variables following shadcn/ui's naming convention (background, foreground, primary, muted, border, etc.) so generated tokens drop into shadcn-based components.
shadcn/ui export
Dark mode token pairing
Generating a light and dark theme together from the same semantic roles, so surfaces, text, and accents stay consistent in meaning across both modes instead of being re-picked independently.
Surface color
A token role for backgrounds at different elevations (page, card, panel, popover), used to create visual separation between layered UI elements.
Muted text
A lower-emphasis text color token used for secondary labels, metadata, and captions. A common accessibility failure point because it's often pushed past readable contrast for visual quietness.
Accent color
The token used for primary actions and highlights (buttons, links, active states) that needs to stay visible against multiple surface colors.
Color palette generator
A tool that produces a set of colors, typically from a seed color, harmony rule, or style preset. The starting point before tokens, accessibility checks, or exports.
Accessible color palette generator
Accessible color palette
A palette where the foreground/background pairs you actually use in UI meet WCAG contrast targets, not just a visually pleasing set of swatches.
How to create an accessible color palette
Color harmony
Relationships between hues on the color wheel (complementary, analogous, triadic) used as a starting rule for generating palettes that feel cohesive.
UI color system
The full structure of how color is organized in a product: backgrounds, surfaces, text, borders, states, and dark mode, not just a brand palette.
UI color systems guide

Want a term added? Email info@chromui.app.