Claude — decoded design system

claude.com · light · modern · custom · deep decode — measured live

Claude's design system, decoded live by Mozaika: measured color roles, type scale, buttons with real hover/focus states, motion and the brand's own tokens.

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

Decoded design system

Claude's decoded design system: background #FAF9F5, text #141413, accent #141413, link #FAF9F5, primary #C6613F; type scale h1 72px / h2 52px / body 16px; 4px spacing base; 6px base radius. The single interactive/action color is #141413 — used only on interactive or must-notice elements (buttons, links, key highlights), never on large fills.

Color roles

Using these colors

• Action color #141413 — the single interactive color; only on things you click or must notice, never large fills.
• accent, button_bg are all #141413 — one role, not several (the action color).
• accent #141413 — 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 #C6613F — a brand color — but the call-to-action uses #141413, not this.
• link #FAF9F5 — fails contrast on the background (~1.0:1) — this is a dark UI color, NOT a readable link; use the text or action color for links (verify against the reference).
• secondary #FEBC2E — 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: anthropicSerif
• Body: anthropicSans
• h1: 72px
• h2: 52px
• body: 16px

Spacing

• base unit: 4px
• scale: 2px, 4px, 6px, 8px, 12px, 16px, 20px, 24px, 28px, 32px

Radii

• base: 6px
• button: 8px

Shadow

rgb(20, 20, 19) 0px 0px 0px 0px

Shadows (elevation)

• subtle: rgb(20, 20, 19) 0px 0px 0px 0px
• card: rgba(0, 0, 0, 0.016) 0px 4px 24px 0px, rgba(0, 0, 0, 0.016) 0px 4px 32px 0px, rgba(0, 0, 0, 0.01) 0px 2px 64px 0px, rgba(0, 0, 0, 0.01) 0px 16px 32px 0px
• overlay: color(srgb 0.85098 0.466667 0.341177 / 0.1) 0px 4px 20px 0px

Motion

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

• durations: 200ms · 100ms · 300ms
• easings: ease · ease-in-out
• animated properties: color, transform, opacity, background-color

Native design tokens

…and 110 more measured on the page.

Button states (measured)

• primary hover: box-shadow rgb(20, 20, 19) 0px 0px 0px 2px
• primary focus: outline 2px solid rgb(44, 132, 219)

Layout (measured)

• container max-width: 660px
• nav: 84px fixed
• common grid: 2 columns

Motion choreography (measured)

Load order: header.NavBar-module-scss-modul → span.LoginCard-module-scss-mo → span.Tabs-module-scss-module_ → span.Tabs-module-scss-module_ → main → main

Scroll reveal: 3 elements rest at opacity 0, animate in over 1s cubic-bezier(0.25, 1, 0.5, 1).

Stagger: span ×3 — 200ms apart.

Overlay recipe (measured)

dialog panel: rgba(0, 0, 0, 0) · radius 0px

Themes

dark counterpart: background #141413, text #FAF9F5.

Responsive (measured)

• breakpoints: 566px · 600px · 768px · 833px · 900px · 991px
• mobile (390px): hero 51px · nav hamburger

Install it

Drop this measured system into any shadcn/Tailwind project in one command:

npx shadcn add mozaika.design/r/decode/claude.com

registry item · or query it over MCP: get_design_system("Claude")

Export: DESIGN.md

# Claude — Design System

> light, modern, medium, custom — deep decode (measured live)

## Colors

| Role | Value |
|------|-------|
| bg | `#FAF9F5` |
| surface | `#ECEBE7` |
| border | `#D7D6D3` |
| text | `#141413` |
| text_muted | `#6B6B68` |
| primary | `#C6613F` |
| accent | `#141413` |
| link | `#FAF9F5` |
| secondary | `#FEBC2E` |
| button_bg | `#141413` |
| button_text | `#FAF9F5` |

**Using these colors**

- **Action color** `#141413` — the single interactive color; it appears only on things you click or must notice (buttons, key highlights), never on large fills or backgrounds.
- `accent`, `button_bg` are all `#141413` — one role, not several (your action color).
- **accent** `#141413` — 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** `#C6613F` — a brand color — but the call-to-action uses #141413, not this.
- **link** `#FAF9F5` — fails contrast on the background (~1.0:1) — this is a dark UI color, NOT a readable link; use the text or action color for links (verify against the reference).
- **secondary** `#FEBC2E` — 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): `#FAF9F5` 85.9% · `#161615` 11.1% · `#898885` 2.9%

## Typography

- Heading: **anthropicSerif** _(free fallback: Newsreader)_
- Body: **anthropicSans** _(free fallback: Newsreader)_

| Role | Size / weight · line-height · tracking |
|------|------------------------------------------|
| hero | 72px / 330 · lh 79px |
| h2 | 52px / 500 · lh 62px |
| h3 | 30px / 400 · lh 36px |
| body | 16px / 400 · lh 26px |
| small | 15px / 400 · lh 24px |

- Weight ladder: 330 · 400 · 500 · 600 · 700 — use these exact measured weights, not the 400/600 defaults.

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

## Spacing
- base unit: 4px (inferred from the measured scale)
- measured scale: 2px, 4px, 6px, 8px, 12px, 16px, 20px, 24px, 28px, 32px — snap all gaps/padding to these
- section rhythm: 128px top/bottom padding per section (measured)

## Radius
- base: 6px
- button: 8px
- card: 4px

## Buttons

| Button | Fill / text | Border | Radius | Padding | Font | Shadow |
|--------|-------------|--------|--------|---------|------|--------|
| primary | `#141413` / `#FAF9F5` | none | 8px | 8px 12px 8px 12px | 400 15px | rgb(20, 20, 19) 0px 0px 0px 0px |
| secondary | `#FAF9F5` / `#141413` | 1px solid rgb(209, 207, 197) | 9.6px | 0px 20px 0px 20px | 600 17px | none |

**States (measured, not guessed)**

- primary hover: box-shadow `rgb(20, 20, 19) 0px 0px 0px 2px`
- primary focus: outline `2px solid rgb(44, 132, 219)`
- secondary hover: background `#F5F4ED`
- transition: `color 0.1s ease-in-out`

## Shadows (elevation)
- subtle: `rgb(20, 20, 19) 0px 0px 0px 0px`
- card: `rgba(0, 0, 0, 0.016) 0px 4px 24px 0px, rgba(0, 0, 0, 0.016) 0px 4px 32px 0px, rgba(0, 0, 0, 0.01) 0px 2px 64px 0px, rgba(0, 0, 0, 0.01) 0px 16px 32px 0px`
- button: `rgb(20, 20, 19) 0px 0px 0px 0px`
- overlay: `color(srgb 0.85098 0.466667 0.341177 / 0.1) 0px 4px 20px 0px`

## Motion
- durations: 200ms (dominant) · 100ms · 300ms
- easings: `ease` (dominant) · `ease-in-out`
- animated properties: color, transform, opacity, background-color

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 |
|-------|-------|
| `--color-gray-000` | `#fff` |
| `--color-gray-050` | `#faf9f5` |
| `--color-gray-100` | `#f5f4ed` |
| `--color-gray-150` | `#f0eee6` |
| `--color-gray-200` | `#e8e6dc` |
| `--color-gray-250` | `#dedcd1` |
| `--color-gray-300` | `#d1cfc5` |
| `--color-gray-350` | `#c2c0b6` |
| `--color-gray-400` | `#b0aea5` |
| `--color-gray-450` | `#9c9a92` |
| `--color-gray-500` | `#87867f` |
| `--color-gray-550` | `#73726c` |

_…and 108 more measured on the page._

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

## Layout (measured)
- container max 660px · common grid: 2-col
- nav: 84px fixed · bg #FAF9F5

| Section (y) | Height | Cols | Gap | Pad y | Split |
|---|---|---|---|---|---|
| 0 | 876 | 2 | 48 | 104/0 | — |
| 876 | 1409 | 3 | 32 | 128/64 | — |
| 2285 | 681 | — | — | 128/128 | — |

## Motion choreography (measured)
Load order: `header.NavBar-module-scss-modul` @0ms → `span.LoginCard-module-scss-mo` @109ms → `span.Tabs-module-scss-module_` @109ms → `span.Tabs-module-scss-module_` @109ms → `main` @156ms → `main` @156ms
- `header.NavBar-module-scss-modul` — opacity 0→1 · transform translateY(-20px)→translateY(0px) — 1000ms cubic-bezier(0.25, 1, 0.5, 1)
- stagger: `span` ×3 — 200ms apart
- scroll reveal: 3 elements rest at opacity 0, animate in over 1s cubic-bezier(0.25, 1, 0.5, 1) (3 revealed during the drive).
- overlay dialog (auto-opened): panel rgba(0, 0, 0, 0) · r 0px

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

## Components (measured)
- link: #87867F · underline — hover #FAF9F5

## Themes (both measured)
- dark counterpart: bg `#141413` · text `#FAF9F5`
- tokens that flip between modes:
  - `--theme-background-primary`: `#faf9f5` → `#141413`
  - `--theme-background-secondary`: `#f5f4ed` → `#1a1918`
  - `--theme-background-tertiary`: `#f0eee6` → `#262624`
  - `--theme-background-overlay`: `#fff` → `#1a1918`
  - `--theme-border-primary`: `#b0aea5` → `#5e5d59`
  - `--theme-border-secondary`: `#d1cfc5` → `#3d3d3a`
  - `--theme-border-tertiary`: `#e8e6dc` → `#30302e`
  - `--theme-foreground-primary`: `#141413` → `#faf9f5`

## Responsive (measured)
- breakpoints: 566px · 600px · 768px · 833px · 900px · 991px
- mobile (390px): hero 51px · body 15px · 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.

← All decoded design systems

An automated reading of Claude's publicly-visible CSS (colors, fonts, spacing, motion) — not affiliated with claude.com. No screenshots stored. Removal requests: hello@mozaika.design.