Duolingo — Design System

Name: Duolingo design system
Creator: Mozaika
Keywords: design system, design tokens, Duolingo, light, custom

light · playful · high · custom · confidence 92%

Duolingo speaks in mascot: custom Feather Bold at 48-64px in the brand's own #58CC02 green — lowercase, chunky, unmistakably the owl's voice — with duolingo-sans at 17px for instructions. 12px-radius buttons wear the signature hard-shadow 3D press, characters bounce through every section, and the whole system feels like game UI because pedagogically, it is.

Open in Mozaika →

This is a static, crawlable rendering for search & AI engines. The interactive version — filters, live decode console, copy & export — is at https://mozaika.design/ds/duolingo.

Tokens

Duolingo's decoded design system: background #FFFFFF, text #777777, accent #100F3E, link #100F3E, primary #1CB0F6; type scale h1 32px / h2 48px / body 17px; 4px spacing base; 3px base radius. The single interactive/action color is #100F3E — used only on interactive or must-notice elements (buttons, links, key highlights), never on large fills.

Color roles

Role	Value
bg	`#FFFFFF`
surface	`#F6F6F6`
border	`#EAEAEA`
text	`#777777`
text_muted	`#AAAAAA`
primary	`#1CB0F6`
accent	`#100F3E`
link	`#100F3E`
secondary	`#0000EE`
button_bg	`#100F3E`
button_text	`#000437`

Using these colors

Action color #100F3E — the single interactive color; only on things you click or must notice, never large fills.
accent, link, button_bg are all #100F3E — one role, not several (the action color).
accent #100F3E — THE accent / action color — interactive & must-notice only (buttons, links, focus, one key highlight); never large fills or backgrounds. Scarcity is what makes it read as designed.
primary #1CB0F6 — a brand color — but the call-to-action uses #100F3E, not this.
secondary #0000EE — optional secondary accent — LOW decode confidence; use rarely (a status color or a single decorative moment) or omit it entirely. Prefer one accent unless the reference clearly shows two.

Typography

Heading: Duolingo Sans
Body: Duolingo Sans
h1: 32px
h2: 48px
body: 17px

Spacing

base unit: 4px
scale: 2px, 4px, 6px, 8px, 12px, 16px, 24px, 32px

Radii

base: 3px
button: 12px

Per-section tokens (12)

Export: DESIGN.md

# Duolingo — Design System

> light, playful, high, custom

Duolingo speaks in mascot: custom Feather Bold at 48-64px in the brand's own #58CC02 green — lowercase, chunky, unmistakably the owl's voice — with duolingo-sans at 17px for instructions. 12px-radius buttons wear the signature hard-shadow 3D press, characters bounce through every section, and the whole system feels like game UI because pedagogically, it is.

## Colors

| Role | Value |
|------|-------|
| bg | `#FFFFFF` |
| surface | `#F6F6F6` |
| border | `#EAEAEA` |
| text | `#777777` |
| text_muted | `#AAAAAA` |
| primary | `#1CB0F6` |
| accent | `#100F3E` |
| link | `#100F3E` |
| secondary | `#0000EE` |
| button_bg | `#100F3E` |
| button_text | `#000437` |

**Using these colors**

- **Action color** `#100F3E` — the single interactive color; it appears only on things you click or must notice (buttons, key highlights), never on large fills or backgrounds.
- `accent`, `link`, `button_bg` are all `#100F3E` — one role, not several (your action color).
- **accent** `#100F3E` — THE accent / action color — interactive & must-notice only (buttons, links, focus, one key highlight); never large fills or backgrounds. Scarcity is what makes it read as designed.
- **primary** `#1CB0F6` — a brand color — but the call-to-action uses #100F3E, not this.
- **secondary** `#0000EE` — optional secondary accent — LOW decode confidence; use rarely (a status color or a single decorative moment) or omit it entirely. Prefer one accent unless the reference clearly shows two.

## Typography

- Heading: **Duolingo Sans** _(free fallback: Newsreader)_
- Body: **Duolingo Sans** _(free fallback: Newsreader)_
- h1: 32px
- h2: 48px
- body: 17px

> **Fonts —** Duolingo Sans may be proprietary — safe free fallback: Newsreader (Google Fonts).

## Spacing
- base unit: 4px
- scale: 2px, 4px, 6px, 8px, 12px, 16px, 24px, 32px

## Radius
- base: 3px
- button: 12px

## Primary button
- bg `#100F3E` · text `#000437` · radius 12px

## How to apply
Paste the Tailwind `@theme` (or CSS variables) as your base, then build each
section to its spec — verify every color, radius, and font against these tokens.

Export: Tailwind v4 (@theme)

@theme {
  /* action color #100F3E — the one interactive color; buttons/links/emphasis only, never large fills. */
  --color-bg: #FFFFFF;
  --color-surface: #F6F6F6;
  --color-border: #EAEAEA;
  --color-text: #777777;
  --color-text-muted: #AAAAAA;
  --color-primary: #1CB0F6;  /* a brand color — but the call-to-action uses #100F3E, not this. */
  --color-accent: #100F3E;  /* THE accent / action color — interactive & must-notice only (buttons, links, focus, one key highlight); never large fills or backgrounds. Scarcity is what makes it read as designed. */
  --color-link: #100F3E;  /* inline text links — shares the action color. */
  --color-secondary: #0000EE;  /* optional secondary accent — LOW decode confidence; use rarely (a status color or a single decorative moment) or omit it entirely. Prefer one accent unless the reference clearly shows two. */
  --color-button-bg: #100F3E;  /* primary-button fill — the main call-to-action color. */
  --color-button-text: #000437;
  /* fonts: Duolingo Sans may be proprietary — safe free fallback: Newsreader (Google Fonts). */
  --font-heading: "Duolingo Sans", "Newsreader", system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-body: "Duolingo Sans", "Newsreader", system-ui, -apple-system, 'Segoe UI', sans-serif;
  --text-h1: 32px;
  --text-h2: 48px;
  --text-body: 17px;
  --radius-base: 3px;
  --radius-button: 12px;
  --spacing-1: 2px;
  --spacing-2: 4px;
  --spacing-3: 6px;
  --spacing-4: 8px;
  --spacing-5: 12px;
  --spacing-6: 16px;
  --spacing-7: 24px;
  --spacing-8: 32px;
}

Export: CSS variables

:root {
  /* action color #100F3E — the one interactive color; buttons/links/emphasis only, never large fills. */
  --bg: #FFFFFF;
  --surface: #F6F6F6;
  --border: #EAEAEA;
  --text: #777777;
  --text-muted: #AAAAAA;
  --primary: #1CB0F6;  /* a brand color — but the call-to-action uses #100F3E, not this. */
  --accent: #100F3E;  /* THE accent / action color — interactive & must-notice only (buttons, links, focus, one key highlight); never large fills or backgrounds. Scarcity is what makes it read as designed. */
  --link: #100F3E;  /* inline text links — shares the action color. */
  --secondary: #0000EE;  /* optional secondary accent — LOW decode confidence; use rarely (a status color or a single decorative moment) or omit it entirely. Prefer one accent unless the reference clearly shows two. */
  --button-bg: #100F3E;  /* primary-button fill — the main call-to-action color. */
  --button-text: #000437;
  --font-heading: "Duolingo Sans", "Newsreader", system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-body: "Duolingo Sans", "Newsreader", system-ui, -apple-system, 'Segoe UI', sans-serif;
  --radius: 3px;
  --radius-button: 12px;
}
/* fonts: Duolingo Sans may be proprietary — safe free fallback: Newsreader (Google Fonts). */