---
version: alpha
name: React
description: Light design system extracted from react.dev (DOM-true values, Emblematic extractor 0.2.0, 2026-11-12).
colors:
  background: "#FFFFFF"
  surface: "#EBECF0"
  on-surface-variant: "#404756"
  on-surface: "#23272F"
  primary: "#087EA4"
  outline: "#23272F1A"
  color-7: "#BCC1CD"
  color-8: "#16181D"
  color-9: "#F6F7F9"
  color-10: "#FFFFFFE6"
  color-11: "#99A1B333"
  color-12: "#5E687E"
  on-primary: "#FFFFFF"
  background-dark: "#23272F"
  on-surface-dark: "#F6F7F9"
  surface-dark: "#16181D"
  primary-dark: "#58C4DC"
  outline-dark: "#F6F7F91A"
typography:
  display-lg:
    fontFamily: Optimistic Display
    fontSize: 52px
    fontWeight: 600
    lineHeight: 1.375
  title-md:
    fontFamily: Optimistic Text
    fontSize: 15px
    fontWeight: 700
    lineHeight: 1.25
  body-md:
    fontFamily: Optimistic Text
    fontSize: 20px
    fontWeight: 400
    lineHeight: 1.5
  label-md:
    fontFamily: Optimistic Text
    fontSize: 13px
    fontWeight: 500
    lineHeight: 2.308
  mono-md:
    fontFamily: Source Code Pro
    fontSize: 13.6px
    fontWeight: 400
    lineHeight: 1.765
rounded:
  sm: 8px
  md: 16px
  full: 9999px
spacing:
  xxs: 2px
  xs: 4px
  sm: 6px
  md: 8px
  lg: 10px
  xl: 12px
  2xl: 16px
  3xl: 20px
  4xl: 24px
  5xl: 32px
  6xl: 40px
  7xl: 64px
  8xl: 80px
  9xl: 128px
  base: 4px
  container: 768px
components:
  button-primary:
    backgroundColor: "{colors.primary}"
    textColor: "{colors.background}"
    rounded: "{rounded.full}"
    padding: 12px
    height: 47.4px
    typography: "{typography.label-md}"
  card:
    backgroundColor: "{colors.background}"
    rounded: "{rounded.md}"
    padding: 0px
  input:
    backgroundColor: "{colors.surface}"
    rounded: "{rounded.full}"
    padding: 16px
    height: 40px
---

# React

> Extracted from [https://react.dev/](https://react.dev/) on 2026-11-12 by Emblematic. Every value below was read from the rendered DOM (computed styles, `document.fonts`, and the fonts Chrome actually used to paint text), not estimated from pixels. When the YAML front matter and this prose disagree, the YAML wins. Copy values from this file exactly; don't transcribe them from memory. Don't copy logos, imagery, illustrations or marketing copy.

## Overview

React uses a light canvas (#FFFFFF) with a palette led by #087EA4. Type is set in **Optimistic Text**, **Optimistic Display** (display), **Source Code Pro** (mono), with 20px body text. Layout: 768px container, top-sticky+blur navigation, 11 sections. Built with next.js, tailwind, google-tag-manager, vercel.

## Colors

Area-weighted from painted backgrounds, text and borders on the 1440px light capture. Roles are inferred from usage (largest background, most text, interactive fills). Every hex is an exact computed value; a role marked *unverified* is a best guess that has not passed review, so its canonical token (e.g. `primary`) is left out of the front matter.

| Token | Hex | OKLCH | Role | Share of paint | CSS variable |
|---|---|---|---|---|---|
| `background` | `#FFFFFF` | 1 0 0 | bg | 72.1% | `--docsearch-hit-background` |
| `surface` | `#EBECF0` | 0.943 0.005 275 | surface | 6.8% | — |
| `on-surface-variant` | `#404756` | 0.398 0.027 265.4 | muted | 5.1% | — |
| `on-surface` | `#23272F` | 0.272 0.016 264.3 | text | 4.1% | — |
| `primary` | `#087EA4` | 0.555 0.107 228.4 | accent | 0.28% | `--docsearch-highlight-color` |
| `outline` | `#23272F1A` (on bg `#E9E9EA`) | 0.272 0.016 264.3 | border | 0.06% | — |
| `color-7` | `#BCC1CD` | 0.811 0.018 267.8 | other | 6.5% | — |
| `color-8` | `#16181D` | 0.209 0.01 268.2 | other | 1.5% | — |
| `color-9` | `#F6F7F9` | 0.976 0.003 264.5 | other | 1.3% | — |
| `color-10` | `#FFFFFFE6` (on bg `#FFFFFF`) | 1 0 0 | other | 1.1% | — |
| `color-11` | `#99A1B333` (on bg `#EBECF0`) | 0.708 0.028 266.5 | other | 0.46% | — |
| `color-12` | `#5E687E` | 0.517 0.037 265.9 | other | 0.42% | — |

Sparse chromatic highlights (not accents): `#58C4DC`.

Declared brand/accent tokens: `--docsearch-primary-color` = `#0074A6` (declared, not painted on this page).

Contrast: text on background 14.97:1, muted text 9.32:1, accent 4.64:1.

Gradients in use: `conic-gradient(from 90deg at -10% 100%, rgb(188, 193, 205) 0deg, rgb(188, 193, 205) 90deg, rgb(255, 255, 255) 360deg)`; `conic-gradient(from -90deg at 110% 100%, rgb(255, 255, 255) 0deg, rgb(235, 236, 240) 90deg, rgb(235, 236, 240) 360deg)`.

The site responds to `prefers-color-scheme: dark`; the `-dark` tokens hold the dark-mode roles.

## Typography

| Family | Role | Weights | Share of text | Source |
|---|---|---|---|---|
| **Optimistic Text** | body | 400, 500, 600, 700 | 65.0% | webfont |
| **Optimistic Display** | display | 400, 600 | 25.8% | webfont |
| **Source Code Pro** | mono | 400 | 9.3% | webfont |

Scale (px): 11, 13, 13.5, 15, 17, 20, 28, 32, 52. Effective ratio ≈ 1.375 (close to a augmented fourth). Body 20px at line-height 1.5; display 52px with tracking 0em. Headings are sentence case. On a 390px viewport the body is 17px and display 40px.

## Layout

Spacing follows a 4px base unit; the most used steps are 2, 4, 6, 8, 10, 12, 16, 20, 24, 32, 40, 64, 80, 128px. Sections open with about 113px of space before their first line of text. Content sits in a 768px container on a 5-column grid. Text density 0.146 (text area / page area).

Section order (desktop). Kinds below the review threshold are shown as *section*:

1. **nav** (64px, bg #FFFFFF)
2. **logos** (64px, bg #FFFFFF)
3. **hero** — “React” (416px, bg #FFFFFF)
4. **section** — “Create user interfaces from components” (1164px, bg #FFFFFF)
5. **section** — “3 Videos” (1132px, bg #FFFFFF)
6. **section** — “5 Videos” (1186px, bg #FFFFFF)
7. **section** — “Go full-stack with a framework” (1160px, bg #FFFFFF)
8. **section** — “Use the best from every platform” (1367px, bg #FFFFFF)
9. **section** — “Vulnerability in React Server Components” (846px, bg #FFFFFF)
10. **section** — “Welcome to the React community” (1342px, bg #FFFFFF)
11. **footer** (366px, bg #FFFFFF)

## Elevation & Depth

Style: subtle. Most used shadows:

- `rgba(0, 0, 0, 0.1) 0px 4px 6px -1px, rgba(0, 0, 0, 0.06) 0px 2px 4px -1px`
- `rgba(0, 0, 0, 0.1) 0px 16px 32px -16px`

## Shapes

Dominant corner radius 16px; radii in use: 8px, 16px, pill. Borders: regular (2px).

## Components

- **button-primary**: backgroundColor `#087EA4`, textColor `#FFFFFF`, rounded `9999px`, padding `12px 24px`, height `47.4px`, fontFamily `Optimistic Text`, fontSize `17px`, fontWeight `700` (e.g. “Learn React”)
- **card**: rounded `16px`, padding `0px`, backgroundColor `#FFFFFF`, shadow `rgba(0, 0, 0, 0) 0px 0px 0px 0px, rgba(0, 0, 0, 0) 0px 0px 0px 0px, rgba(0, 0, 0, 0.1) 0px 16px 32px -16px, rgba(0, 0, 0`
- **input**: rounded `9999px`, height `40px`, padding `16px 0px`, backgroundColor `#EBECF0`

## Do's and Don'ts

- Do reserve `#087EA4` for primary actions and highlights; it covers only 0.28% of the painted page.
- Do set body copy in Optimistic Text at 20px / 1.5.
- Do use Optimistic Display only for display sizes, not for body text.
- Don't introduce font weights beyond 400, 500, 600, 700.
- Do keep corners at 16px for most controls, and use the larger radii only for cards and media.
- Do snap spacing to multiples of 4px.
- Don't copy this site's logos, illustrations, photography or copy; use the system, not the brand assets.

## Provenance

Spec v2, extractor 0.2.0. Render quality: **ok**. Vision pass: not run. Fields below confidence 0.7 are hedged or left out above: `color.accent_strategy`, `layout.columns`, `layout.hero`, `layout.section_count`, `sections[].kind`, `space.section_padding_px`. Full per-field provenance is in `spec.json`.