Braintrust — decoded design system

braintrust.dev · light · modern · tailwind · deep decode — measured live

Braintrust'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/braintrust.dev.

Decoded design system

Braintrust's decoded design system: background #FFFFFF, text #000000, accent #2C1FEA, link #FFFFFF, primary #2C1FEA; type scale h1 60px / h2 48px / body 14px; 4px spacing base; 4px base radius. The single interactive/action color is #2C1FEA — used only on interactive or must-notice elements (buttons, links, key highlights), never on large fills.

Color roles

Using these colors

• Action color #2C1FEA — the single interactive color; only on things you click or must notice, never large fills.
• primary, accent, button_bg are all #2C1FEA — one role, not several (the action color).
• accent #2C1FEA — 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.
• link #FFFFFF — 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 #1E2939 — 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: Inter
• Body: btSans
• Mono: suisseMono
• h1: 60px
• h2: 48px
• body: 14px

Spacing

• base unit: 4px
• scale: 2px, 4px, 6px, 8px, 12px, 16px, 20px, 24px, 32px, 64px

Radii

• base: 4px
• button: 24px

Motion

Micro-interactions run at 150ms (dominant) with cubic-bezier(0.4, 0, 0.2, 1).

• durations: 150ms · 200ms · 300ms
• easings: cubic-bezier(0.4, 0, 0.2, 1) · cubic-bezier(0, 0, 0.2, 1)
• animated properties: color, background-color, border-color, outline-color

Native design tokens

…and 110 more measured on the page.

Button states (measured)

• primary hover: border-radius 0px · background #000000
• primary focus: outline 1px auto rgb(16, 16, 16)

Layout (measured)

• container max-width: 1440px
• nav: 56px sticky
• common grid: 2 columns

Motion choreography (measured)

Load order: div.transition-all×3 → div.-mx-48 → div.w-full×2 → div.p-0×3 → svg.lucide → div.flex

Scroll reveal: 14 elements rest at opacity 0, translateY(20px), animate in over 0.5s cubic-bezier(0, 0, 0.2, 1).

Stagger: div ×7 — 100ms apart.

Responsive (measured)

• mobile (390px): hero 48px · nav hamburger

Install it

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

npx shadcn add mozaika.design/r/decode/braintrust.dev

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

Export: DESIGN.md

# Braintrust — Design System

> light, modern, high, tailwind — deep decode (measured live)

## Colors

| Role | Value |
|------|-------|
| bg | `#FFFFFF` |
| surface | `#EFEFEF` |
| border | `#D8D8D8` |
| text | `#000000` |
| text_muted | `#606060` |
| primary | `#2C1FEA` |
| accent | `#2C1FEA` |
| link | `#FFFFFF` |
| secondary | `#1E2939` |
| button_bg | `#2C1FEA` |
| button_text | `#FFFFFF` |

**Using these colors**

- **Action color** `#2C1FEA` — the single interactive color; it appears only on things you click or must notice (buttons, key highlights), never on large fills or backgrounds.
- `primary`, `accent`, `button_bg` are all `#2C1FEA` — one role, not several (your action color).
- **accent** `#2C1FEA` — 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.
- **link** `#FFFFFF` — 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** `#1E2939` — 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): `#FFFFFF` 90% · `#D4D7E6` 2.1% · `#EBEFF3` 1.9% · `#9895C9` 1.8%

## Typography

- Heading: **Inter**
- Body: **btSans** _(free fallback: Newsreader)_
- Mono: **suisseMono**

| Role | Size / weight · line-height · tracking |
|------|------------------------------------------|
| hero | 60px / 400 · lh 60px |
| h2 | 48px / 400 · lh 48px |
| h3 | 24px / 600 · lh 32px |
| body | 14px / 400 · lh 20px |
| small | 12px / 400 · lh 16px |
| eyebrow | 12px / 400 · tracking 0.6px |

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

> **Fonts —** Inter — free, on Google. btSans 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, 32px, 64px — snap all gaps/padding to these

## Radius
- base: 4px
- button: 24px
- card: 6px
- pill: 9999px

## Buttons

| Button | Fill / text | Border | Radius | Padding | Font | Shadow |
|--------|-------------|--------|--------|---------|------|--------|
| primary | `#2C1FEA` / `#FFFFFF` | none | 24px | 0px 12px 0px 12px | 600 15px | none |
| secondary | `rgba(0, 0, 0, 0)` / `#323131` | none | 4px | 0px 12px 0px 12px | 600 15px | none |

**States (measured, not guessed)**

- primary hover: border-radius `0px` · background `#000000`
- primary focus: outline `1px auto rgb(16, 16, 16)`
- secondary hover: border-radius `24px` · color `#18181B`
- transition: `all 0.2s cubic-bezier(0.4, 0, 0.2, 1)`

## Motion
- durations: 150ms (dominant) · 200ms · 300ms
- easings: `cubic-bezier(0.4, 0, 0.2, 1)` (dominant) · `cubic-bezier(0, 0, 0.2, 1)`
- animated properties: color, background-color, border-color, outline-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-purple-200` | `lab(87.8405% 13.4282 -18.7159)` |
| `--color-purple-300` | `lab(78.3298% 26.2195 -34.9499)` |
| `--color-zinc-200` | `lab(90.6853% .399232 -1.45452)` |
| `--color-slate-200` | `lab(91.7353% -.998765 -4.76968)` |
| `--color-sky-500` | `lab(63.3038% -18.433 -51.0407)` |
| `--color-neutral-300` | `lab(84.92% 0 -.0000119209)` |
| `--color-slate-500` | `lab(48.0876% -2.03595 -16.5814)` |
| `--color-purple-800` | `lab(30.6017% 56.7637 -64.4751)` |
| `--muted` | `#f5f5f5` |
| `--color-gray-300` | `lab(85.1236% -.612259 -3.7138)` |
| `--color-yellow-400` | `lab(83.2664% 8.65132 106.895)` |
| `--color-slate-300` | `lab(84.7652% -1.94535 -7.93337)` |

_…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 1440px · common grid: 2-col
- nav: 56px sticky · bg #FFFFFF

| Section (y) | Height | Cols | Gap | Pad y | Split |
|---|---|---|---|---|---|
| 56 | 644 | — | — | 0/0 | — |
| 732 | 220 | 8 | 4 | 0/0 | — |
| 1000 | 640 | — | — | 0/0 | — |

## Motion choreography (measured)
Load order: `div.transition-all`×3 @0ms → `div.-mx-48` @1623ms → `div.w-full`×2 @1623ms → `div.p-0`×3 @1623ms → `svg.lucide` @2380ms → `div.flex` @2382ms
- `div.flex` — opacity 1→1 — 2000ms cubic-bezier(0.4, 0, 0.6, 1) · loops
- `svg.lucide` — transform rotate(0deg)→rotate(360deg) — 1500ms cubic-bezier(0.72, 0.29, 0.22, 0.65) · loops
- stagger: `div` ×7 — 100ms apart
- scroll reveal: 14 elements rest at opacity 0, translateY(20px), animate in over 0.5s cubic-bezier(0, 0, 0.2, 1) (12 revealed during the drive).

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

## Components (measured)
- link: #094135 · no underline
- disabled: bg rgba(0, 0, 0, 0) · text #000000

## Responsive (measured)
- mobile (390px): hero 48px · body 16px · 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.

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