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Building a Design System

This guide walks through building a design-system styling layer on top of Tasty — defining tokens, state aliases, recipes, primitive components, and compound components with sub-elements.

It assumes you have already decided to adopt Tasty. The goal is not just to centralize tokens, but to define a styling language whose component states resolve deterministically across variants, responsive rules, and sub-elements. For evaluation criteria, audience fit, and incremental adoption phases, see the Adoption Guide. For the recommended component patterns and mental model, see Methodology.

Designing your token vocabulary

Tokens are the foundation of a design system. In Tasty, tokens are defined via configure({ tokens }) and referenced in styles with #name (colors) or $name (values). See Configuration — Design Tokens for the API.

Color tokens

Adopt a semantic naming convention that maps intent, not visual appearance. Define tokens via configure({ tokens }):

import { configure } from '@tenphi/tasty';

configure({
  tokens: {
    // Surfaces
    '#surface': '#fff',
    '#surface-hover': '#f5f5f5',
    '#surface-pressed': '#ebebeb',

    // Primary action
    '#primary': 'oklch(55% 0.25 265)',
    '#primary-hover': 'oklch(50% 0.25 265)',
    '#primary-pressed': 'oklch(45% 0.25 265)',
    '#on-primary': '#fff',

    // Semantic
    '#danger': 'oklch(55% 0.22 25)',
    '#danger-hover': 'oklch(50% 0.22 25)',
    '#on-danger': '#fff',

    // Text
    '#text': '#111',
    '#text-secondary': '#666',

    // Borders
    '#border': '#e0e0e0',

    // Unit values
    '$gap': '8px',
    '$radius': '4px',
    '$border-width': '1px',
    '$outline-width': '2px',
  },
});

Tokens are injected as CSS custom properties on :root when the first style is rendered. They support state maps for theme-aware values:

configure({
  tokens: {
    '#primary': {
      '': 'oklch(55% 0.25 265)',
      '@dark': 'oklch(75% 0.2 265)',
    },
  },
});

The #on-* convention names the text color that sits on top of a fill — #on-primary is the text color on a #primary background. This makes state maps self-documenting: fill: '#primary' and color: '#on-primary' clearly belong together.

For OKHSL-based palette generation with automatic WCAG contrast solving, see Glaze.

Replace tokens for value aliases

configure({ replaceTokens }) replaces tokens with literal values at parse time, baking them into the generated CSS. Use it for value aliases that should be inlined during style generation:

configure({
  replaceTokens: {
    '$card-padding': '4x',
    '$input-height': '5x',
    '$sidebar-width': '280px',
  },
});

Typography presets

Use generateTypographyTokens() to create typography tokens from your own presets, then pass them to configure({ tokens }):

import { configure, generateTypographyTokens } from '@tenphi/tasty';

const typographyTokens = generateTypographyTokens({
  h1: { fontSize: '2rem', lineHeight: '1.2', letterSpacing: '-0.02em', fontWeight: 700 },
  t2: { fontSize: '0.875rem', lineHeight: '1.5', letterSpacing: 'normal', fontWeight: 400 },
});

configure({
  tokens: {
    ...typographyTokens,
  },
});

Then use preset: 'h1' or preset: 't2' in any component's styles.

Registering brand fonts

Register your design system's custom fonts via configure({ fontFace }) so every component can reference them:

configure({
  fontFace: {
    'Brand Sans': [
      { src: 'url("/fonts/brand-regular.woff2") format("woff2")', fontWeight: 400, fontDisplay: 'swap' },
      { src: 'url("/fonts/brand-bold.woff2") format("woff2")', fontWeight: 700, fontDisplay: 'swap' },
    ],
  },
});

See Font Face for the full configuration reference.

Defining state aliases

State aliases let you write @mobile instead of @media(w < 768px) in every component. Define them once in configure():

configure({
  states: {
    '@mobile': '@media(w < 768px)',
    '@tablet': '@media(768px <= w < 1024px)',
    '@desktop': '@media(w >= 1024px)',
    '@dark': '@root(schema=dark) | (!@root(schema) & @media(prefers-color-scheme: dark))',
    '@reduced-motion': '@media(prefers-reduced-motion: reduce)',
  },
});

Every component can now use these without repeating the query logic:

const Card = tasty({
  styles: {
    padding: { '': '4x', '@mobile': '2x' },
    flow: { '': 'row', '@mobile': 'column' },
    fill: { '': '#surface', '@dark': '#surface-dark' },
  },
});

Without aliases, the same component would need the full media query expression inlined in every state map — across every property, in every component. Aliases eliminate that duplication.

Creating recipes

Recipes are named style bundles for patterns that repeat across components. Define them in configure():

configure({
  recipes: {
    card: {
      padding: '4x',
      fill: '#surface',
      radius: '1r',
      border: true,
    },
    elevated: {
      shadow: '0 2x 4x #shadow',
    },
    'input-reset': {
      border: 'none',
      outline: 'none',
      fill: 'transparent',
      font: true,
      preset: 't3',
    },
    interactive: {
      cursor: { '': 'pointer', disabled: 'not-allowed' },
      opacity: { '': '1', disabled: '.5' },
      transition: 'theme',
    },
  },
});

Components reference recipes by name. This keeps component definitions lean while ensuring consistency:

const ProfileCard = tasty({
  styles: {
    recipe: 'card elevated',
    color: '#text',
    Title: { preset: 'h3', color: '#primary' },
  },
  elements: { Title: 'h2' },
});

Use the / separator when a recipe should be applied after local styles (post-merge), so recipe states take priority:

const Input = tasty({
  styles: {
    recipe: 'input-reset / interactive',
    padding: '1.5x 2x',
    border: '1bw solid #border',
  },
});

See Configuration — Recipes for the API and Style DSL — Recipes for composition patterns.

Building primitive components

Primitives are the layout and utility components that product engineers compose. They expose a controlled set of style props and have minimal opinions about appearance.

Layout primitives

import { tasty, FLOW_STYLES, POSITION_STYLES } from '@tenphi/tasty';

const Space = tasty({
  as: 'div',
  styles: {
    display: 'flex',
    flow: 'column',
    gap: '1x',
  },
  styleProps: FLOW_STYLES,
});

const Box = tasty({
  as: 'div',
  styles: {
    display: 'block',
  },
  styleProps: [...FLOW_STYLES, ...POSITION_STYLES, 'padding', 'fill', 'radius'],
});

const Grid = tasty({
  as: 'div',
  styles: {
    display: 'grid',
    gap: '1x',
  },
  styleProps: [...FLOW_STYLES, 'gridColumns', 'gridRows', 'gridAreas'],
});

Product engineers use these to compose layouts without writing CSS:

<Space flow="row" gap="2x" placeItems="center">
  <Title>Dashboard</Title>
  <Button placeSelf="end">Add Item</Button>
</Space>

<Grid gridColumns={{ '': '1fr', '@tablet': '1fr 1fr', '@desktop': '1fr 1fr 1fr' }} gap="3x">
  <Card>...</Card>
  <Card>...</Card>
  <Card>...</Card>
</Grid>

Which styleProps to expose

Match the prop set to the component's role:

Component categoryRecommended styleProps
Layout containers (Space, Box, Grid)FLOW_STYLES — flow, gap, align, justify, padding, fill
Positioned elements (Button, Badge)POSITION_STYLES — placeSelf, gridArea, order
Text elements['preset', 'color'] or a custom subset
Compound componentsTypically none — styling happens via sub-elements and wrapping

Exposing too many props weakens the design system's constraints. See Methodology — styleProps as the public API for the rationale.

Building compound components

Compound components have inner parts — a card has a title, content, and footer; a dialog has a header, body, and actions. Tasty models these as sub-elements.

const Card = tasty({
  styles: {
    recipe: 'card',
    flow: 'column',
    gap: '2x',

    Title: {
      preset: 'h3',
      color: '#primary',
    },
    Content: {
      preset: 't2',
      color: '#text',
    },
    Footer: {
      display: 'flex',
      flow: 'row',
      gap: '1x',
      justify: 'flex-end',
      padding: '2x top',
      border: '1bw solid #border top',
    },
  },
  elements: {
    Title: 'h2',
    Content: 'div',
    Footer: 'div',
  },
});

Usage:

<Card>
  <Card.Title>Monthly Revenue</Card.Title>
  <Card.Content>
    $1.2M — up 12% from last month.
  </Card.Content>
  <Card.Footer>
    <Button>Details</Button>
  </Card.Footer>
</Card>

Sub-elements share the root component's state context by default. A disabled modifier on <Card> affects Title, Content, and Footer styles automatically — no prop drilling. For the full mental model, see Methodology — Component architecture.

For sub-element syntax details (selector affix $, @own(), elements config), see Runtime API — Sub-element Styling.

Defining the override contract

A design system works best when the rules for customization are explicit. Tasty provides three levels of control:

What product engineers can do

  1. Use styleProps — adjust layout, spacing, positioning through the props the component exposes:
<Space flow="row" gap="3x" padding="2x">
  1. Use modProps — control component states through typed props instead of mods:
<Button isLoading size="large">Submit</Button>
  1. Pass tokens — inject runtime values through the tokens prop for per-instance customization:
<ProgressBar tokens={{ '$progress': `${percent}%` }} />
  1. Create styled wrappers — extend a component's styles with tasty(Base, { styles }):
const DangerButton = tasty(Button, {
  styles: {
    fill: { '': '#danger', ':hover': '#danger-hover' },
    color: '#on-danger',
  },
});

What to discourage

See Methodology — styles prop vs style prop and Methodology — Wrapping and extension for the full rationale.

Project structure

A recommended structure for a design system built on Tasty:

ds/
  config.ts              # configure() — tokens, units, states, recipes
  primitives/
    Space.tsx             # Layout: flex container with FLOW_STYLES
    Box.tsx               # Generic container
    Grid.tsx              # Grid container
    Text.tsx              # Text element with preset + color
  components/
    Button.tsx            # Interactive component with variants
    Card.tsx              # Compound component with sub-elements
    Input.tsx             # Form input with recipes
    Dialog.tsx            # Overlay compound component
  recipes/
    index.ts              # Recipe definitions (imported by config.ts)
  tokens/
    colors.ts             # Color token definitions
    typography.ts         # Typography presets via generateTypographyTokens()
    spacing.ts            # Spacing token definitions
  index.ts                # Public API: re-exports components + configure

The key principle: config.ts imports tokens and recipes, calls configure(), and is imported at the app entry point before any component renders. Components import only from @tenphi/tasty — they reference tokens and recipes by name, not by import.

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