MozaikaDesign system

Duolingo — Design System

light · playful · high · custom · confidence 92% · deep decode

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

RoleValue
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

Typography

Spacing

Radii

Motion

Micro-interactions run at 200ms (dominant) with ease.

Native design tokens

TokenValue
--web-ui_button-border-radius16px
--text-heading-weight-medium700
--text-label-weight-large700
--text-heading-weight-xsmall700
--text-heading-weight-small700
--text-body-weight-bold700
--text-caption-weight-bold700
--text-body-weight-spacious-bold700
--text-body-weight-spacious500
--text-label-weight-medium700

…and 29 more measured on the page.

Layout (measured)

Motion choreography (measured)

Scroll reveal: 3 elements rest at opacity 0, animate in over 400ms.

Responsive (measured)

Per-section tokens (12)

Export: DESIGN.md

# Duolingo — Design System

> light, playful, high, custom — deep decode (measured live)

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.
- **Page coverage** (full-page screenshot pixels): `#FFFFFF` 89.3% · `#23B3EC` 2.6% · `#5ACF1B` 2.5% · `#BEDFC2` 1.7%

## Typography

- Heading: **Duolingo Sans** _(free fallback: Newsreader)_
- Body: **Duolingo Sans** _(free fallback: Newsreader)_

| Role | Size / weight · line-height · tracking |
|------|------------------------------------------|
| hero | 64px / 700 · tracking -1.28px |
| h2 | 48px / 700 |
| h3 | 32px / 700 |
| body | 17px / 500 · lh 24px |
| small | 15px / 700 · lh 20px · tracking 0.8px |
| eyebrow | 15px / 700 · tracking 0.8px |

- Weight ladder: 400 · 500 · 600 · 700 — use these exact measured weights, not the 400/600 defaults.

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

## Spacing
- base unit: 4px (inferred from the measured scale)
- measured scale: 12px, 16px, 23px, 24px, 30px, 40px, 48px, 70px, 80px, 96px — snap all gaps/padding to these
- section rhythm: 96px top/bottom padding per section (measured)

## Radius
- base: 3px
- button: 12px
- card: 12px
- sharp: 2px

## Buttons

| Button | Fill / text | Border | Radius | Padding | Font | Shadow |
|--------|-------------|--------|--------|---------|------|--------|
| primary | `#1CB0F6` / `#FFFFFF` | none | 12px | 13px 16px 13px 16px | 700 15px / 0.8px | none |
| secondary | `rgba(0, 0, 0, 0)` / `#FFFFFF` | none | 12px | 0px 16px 0px 16px | 700 15px / 0.8px | none |

## Motion
- durations: 200ms (dominant) · 300ms · 400ms
- easings: `ease` (dominant) · `cubic-bezier(0.22, 1, 0.36, 1)`
- animated properties: transform, border-color, filter

Micro-interactions use the dominant duration + easing; nothing on the page animates slower than the longest duration above — don't invent springier motion.

## Their own tokens (verbatim from :root)

| Token | Value |
|-------|-------|
| `--web-ui_button-border-radius` | `16px` |
| `--text-heading-weight-medium` | `700` |
| `--text-label-weight-large` | `700` |
| `--text-heading-weight-xsmall` | `700` |
| `--text-heading-weight-small` | `700` |
| `--text-body-weight-bold` | `700` |
| `--text-caption-weight-bold` | `700` |
| `--text-body-weight-spacious-bold` | `700` |
| `--text-body-weight-spacious` | `500` |
| `--text-label-weight-medium` | `700` |
| `--text-pageTitle-weight-large` | `700` |
| `--text-heading-weight-large` | `700` |

_…and 27 more measured on the page._

Prefer these names when extending their system — it's the brand's actual vocabulary.

## Layout (measured)
- container max 990px · common grid: 2-col
- nav: 900px

| Section (y) | Height | Cols | Gap | Pad y | Split |
|---|---|---|---|---|---|
| 996 | 530 | 2 | 101 | 0/0 | — |
| 1526 | 530 | 2 | 101 | 0/0 | — |
| 2056 | 530 | 2 | 101 | 0/0 | — |
| 2586 | 530 | 2 | 101 | 0/0 | — |
| 3212 | 1289 | — | — | 0/0 | — |
| 4501 | 900 | 2 | 40 | 0/0 | — |

## Motion choreography (measured)
- `div._1ATOC` ×2 — opacity 1→0 — 300ms ease
- scroll reveal: 3 elements rest at opacity 0, animate in over 400ms (0 revealed during the drive).

Rebuild the timeline, not just the durations — order, delays and staggers above are the choreography.

## Components (measured)
- link: #1CB0F6 · no underline

## Responsive (measured)
- breakpoints: 530px · 550px · 699px · 768px · 896px · 1065px
- mobile (390px): hero 32px · body 17px · nav: hamburger

## 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.
Hover/focus states, shadows and motion timings above are measured from the live page — match them exactly, don't re-guess them.

---

> **Decoded with Mozaika** — measured live, not guessed. Full decoded design system + one-command install: mozaika.design/ds/duolingo

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;
  /* measured weights: 400, 500, 600, 700 — use these, not 400/600 */
  --text-hero: 64px; --font-weight-hero: 700; --tracking-hero: -1.28px;
  --text-h2: 48px; --font-weight-h2: 700;
  --text-h3: 32px; --font-weight-h3: 700;
  --text-body: 17px; --font-weight-body: 500; --leading-body: 24px;
  --text-small: 15px; --font-weight-small: 700; --leading-small: 20px; --tracking-small: 0.8px;
  --text-eyebrow: 15px; --font-weight-eyebrow: 700; --tracking-eyebrow: 0.8px;
  --radius-base: 3px;
  --radius-button: 12px;
  --radius-card: 12px;
  --radius-sharp: 2px;
  --ease-brand: ease;
  --duration-fast: 200ms;  /* use: duration-[var(--duration-fast)] */
  --duration-base: 300ms;
  --duration-slow: 400ms;
  --section-y: 96px;  /* per-section vertical padding (measured) */
  --spacing: 4px;  /* measured base — drives the p-*/gap-* scale. steps seen on the page: 12, 16, 23, 24, 30, 40, 48, 70, 80, 96px */
}

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;
  --text-hero: 64px; --weight-hero: 700; --tracking-hero: -1.28px;
  --text-h2: 48px; --weight-h2: 700;
  --text-h3: 32px; --weight-h3: 700;
  --text-body: 17px; --weight-body: 500; --leading-body: 24px;
  --text-small: 15px; --weight-small: 700; --leading-small: 20px; --tracking-small: 0.8px;
  --text-eyebrow: 15px; --weight-eyebrow: 700; --tracking-eyebrow: 0.8px;
  --radius: 3px;
  --radius-button: 12px;
  --radius-card: 12px;
  --radius-sharp: 2px;
  --ease: ease;
  --duration-fast: 200ms;
  --duration-base: 300ms;
  --duration-slow: 400ms;
  --section-y: 96px;
}

/* their own tokens, verbatim from the site's :root */
:root {
  --web-ui_button-border-radius: 16px;
  --text-heading-weight-medium: 700;
  --text-label-weight-large: 700;
  --text-heading-weight-xsmall: 700;
  --text-heading-weight-small: 700;
  --text-body-weight-bold: 700;
  --text-caption-weight-bold: 700;
  --text-body-weight-spacious-bold: 700;
  --text-body-weight-spacious: 500;
  --text-label-weight-medium: 700;
  --text-pageTitle-weight-large: 700;
  --text-heading-weight-large: 700;
}
/* fonts: Duolingo Sans may be proprietary — safe free fallback: Newsreader (Google Fonts). */