# Duolingo — Style Reference
> Green playground with thick marker outlines
**Theme:** light
Source measurements are normalized; roles and recommendations are interpreted. Font summary lists are independent, not paired by position. HTML examples are reconstructions, not source components.
Duolingo is a playful, gamified language-learning canvas: a white background dominated by a single saturated brand green that fills primary actions, with thick, colorful borders giving every interactive element a tactile, pressable quality. The interface pairs a friendly rounded sans-serif for body, nav, and links with a heavy display face for oversized feature headlines, creating a contrast between approachable daily-use type and confident, exclamation-point section headers. Color appears sparingly but decisively — green for primary actions and headings, blue for secondary highlights, and a lighter lime green used extensively as a link/button border for an outlined, glowing treatment. The visual mood is warm, educational, and game-like, with cartoon character illustrations that humanize every product surface.