anthropic.com is built on a warm, off-white canvas (rgb(250, 249, 245)).
The system uses rgb(20, 20, 19) as a near-neutral accent (low saturation).
Sharp 0px corners on CTAs — architectural restraint, engineering precision alongside editorial serif type (Anthropic Serif) — voice of authority.
Anthropic Serif is paired with Anthropic Sans for secondary roles.
A restrained elevation system (1 distinct shadow) — shadows reserved for the few elements that must lift off the page.
Motion is a first-class concern — 5 keyframe animations plus transition-driven interactions.
01
Color — roles, semantics & the full census
11 colors measured · click any swatch to copy
Canvas
#faf9f5
AAA 17.5:1
Ink
#141413
AAA 17.5:1
Accent
#141413
AAA 17.5:1
Line
#141413
AAA 17.5:1
Semantic states
No semantic state colors detected — this system signals state through weight & motion, not hue.
11 colors mined from the live renderexpand
02
Type — the ladder, in the real face
6 roles · rendered live in the real Inter (captured woff2) · lines are editable, click any spec to copy
1 box-shadows measured on the live page · click a tile to copy its raw value
shadow-1
05
Motion — easings, transitions & live keyframes
0 easing curves · 5 keyframes · hover a tile to preview
5 keyframe animations extracted
spin
marquee
fadein
menuOpen
menuClose
06
Components — the closed vocabulary
10 component families · 44 variants counted on the live DOM
Component
Variants found
buttons
×10
cta Banner
×9
nav Links
×6
links
×6
heading H3
×4
heading H2
×3
footer Links
×2
eyebrow Labels
×2
badges
×1
heading H1
×1
Component style specs (§4)expand
Buttons
Ghost
Background: transparent
Text: #141413{colors.hairline}
Padding: 22.4px 12px
Radius: 0px
Font: 20px weight 400
Use: Subtle action, toolbar, nav button
Ghost
Background: transparent
Text: #141413{colors.hairline}
Padding: 0px 0px 0px 12px
Radius: 0px
Font: 20px weight 400
Use: Subtle action, toolbar, nav button
Dark / Solid
Background: #141413{colors.hairline}
Text: #faf9f5{colors.background}
Padding: 8px 16px
Radius: 8px 0px 0px 8px
Border: 1px solid rgb(20, 20, 19)
Font: 16px weight 400
Use: Solid dark CTA
Dark / Solid
Background: #141413{colors.hairline}
Text: #faf9f5{colors.background}
Padding: 8px 16px
Radius: 8px
Border: 1px solid rgb(20, 20, 19)
Font: 16px weight 400
Use: Solid dark CTA
Pill
Background: transparent
Text: #141413{colors.hairline}
Padding: 0px
Radius: 8px
Font: 16px weight 400
Use: Status pills, tags, chips
Light / Invert
Background: #faf9f5{colors.background}
Text: #141413{colors.hairline}
Padding: 12px 31.4776px
Radius: 0px 0px 8px 8px
Font: 18px weight 600
Use: Bright CTA on dark sections
07
Layout — structure & dimensions
4 layout metrics measured
max Widthmin(89.5rem, 100vw)
header Height68px
sidebar Width0px
container Padding0px
08
Responsive — real breakpoints
5 media-query stops read from the live CSS
479px
501px
767px
768px
991px
09
Do's & Don'ts
19 enforceable rules pulled verbatim from the spec
Do
Use Off-White (`#faf9f5`) as the page background — it's intentionally not pure white
Use Near-Black (`#141413`) for text — not pure black, it's warmer and more readable
Use Anthropic Serif as the primary typeface — it defines the brand personality
Use the extracted shadow patterns for elevation — they are tuned to match the brand palette
Use full-pill radius (9999px) only for specific elements (avatars, pills, toggles)
Use Near-Black (`#141413`) as the primary accent — it's the brand's signature interactive color
Use 8px 0px 0px 8px border-radius on buttons — the standard corner rounding for interactive elements
Maintain nav height at 68px — consistent vertical space for the navigation bar
Respect the 4px–32px spacing range — the design uses a wide scale for visual breathing room
Use a 7-column grid on desktop — density matters for this content type
Don't
Don't use pure white (`#ffffff`) as a page background — the warm tone is part of the brand identity
Don't use pure black (`#000000`) for text — the near-black adds warmth
Don't substitute with generic sans-serif or serif — the custom font carries the brand
Don't invent new shadow values — use only the extracted shadow levels
Don't apply pill radius on rectangular buttons or cards — it's reserved for specific interactive elements
Don't introduce additional saturated accent colors — the palette is intentionally controlled
Don't collapse or hide the nav on scroll without an explicit scroll-triggered animation — the design uses fixed nav presence
Don't make the nav sticky — this design lets it scroll away to maximize content focus
Don't put a CTA button in the nav — this design uses links only at the top
10
Agent guide & export
Paste-ready prompt + the real files behind this page
Build a UI in the anthropic.com design system.
Canvas #faf9f5 · ink #141413 · accent #141413.
Type: Anthropic Serif — respect the size/weight ladder in §3.
Radius, spacing, shadow: use only the extracted scales (no magic numbers).
Full spec follows — paste the DESIGN.md below into your agent.