Reverse-engineered design system

Design System
Analysis of Duolingo

A bright, candy-colored, game-like system: a snow-white canvas, soft "eel" grey ink, and one electric Feather Green that owns every call to action — pressed into chunky 3D buttons with a darker-green bottom lip.

01 — Foundations

Colour Palette

02 — Foundations

Typography

Two proprietary faces — duolingo-sans (body / UI) and feather (display) — shown here with their nearest free substitutes, Nunito and Fredoka. Hierarchy is built from size and weight; note the unusually confident 500-weight body text.

03 — Components

Button Variants

button-primary
Feather Green fill, white uppercase label, 12px radius and a solid 4px Mask-Green lip — the signature pressable 3D button.
button-dark
Deep-indigo fill used in the app-download band and the inverted footer.
button-secondary
White fill, Macaw-blue label, 2px Swan border with a matching grey lip.
button-pill
Fully-rounded chip used for language pickers and filters.
04 — Components

Cards & Surfaces

Cards are flat white with a 1px Swan hairline and a 16px radius; they lift with a soft grey glow on hover rather than a heavy drop shadow.

05 — Components

Form Elements

text-input
textarea
06 — Foundations

Spacing Scale

A 4px base unit scaling to a 48px section rhythm.

07 — Foundations

Border Radius

Everything is rounded — 12px dominates buttons, inputs and cards; pills and avatars go fully round.

08 — Foundations

Elevation & Depth

Level 0 — flat surface separated by a 1px Swan hairline. The default.
Level 1 — the chunky solid offset (no blur) that forms the button lip and the brand's tactile, pressable feel.
Level 2 — a soft grey glow reserved for raised popovers and elevated cards.
09 — Responsive

Responsive Behavior

NameWidthKey changes
Mobile< 768pxSingle column; headlines drop toward ~40px; CTAs stretch to full width, keeping radius + green lip.
Tablet768–1023pxTwo-column course / feature grids; colour bands stay full-bleed.
Laptop1024–1279pxUp to four-column grids; content capped to a centered max width.
Desktop≥ 1280pxGenerous whitespace; oversized 64px hero; alternating white / pale-blue / indigo bands.

The personality lives in colour, roundness and weight — so the brand survives every breakpoint even as the layout simplifies to a single column.

Pricing Tiers

Duolingo's plan structure, rendered in-system — a free tier, the popular Super, and Max.

Free
$0/mo
Learn with ads and a limited number of hearts.
  • All language courses
  • Streaks & leaderboards
  • Ad-supported lessons
Super● Most popular
$12.99/mo
No ads, unlimited hearts, and personalized practice.
  • Everything in Free
  • No ads, unlimited hearts
  • Unlimited Legendary & review
Max
$29.99/mo
Everything in Super plus AI-powered features.
  • Everything in Super
  • Explain My Answer
  • Roleplay with AI

Data Table

A weekly league leaderboard, in-system: Swan hairlines, pill status chips, rounded pager.

RankLearnerLeagueStatusXP
#1maria_esDiamondPromoted4,820
#2kenji_jpDiamondPromoted4,510
#3lena_deDiamondHolding3,990
#4amir_frDiamondHolding3,740
#5sofia_itDiamondHolding3,605
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Auth Forms

Sign-in patterns in Duolingo's system — rounded inputs, a green primary action, and social sign-on.

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