biomejs.dev

DESIGN.md

Narrative design system document — paste directly into Claude Code, Cursor, or Bolt.

---
version: alpha
name: biomejs.dev
description: "Light product system built on #ffffff with #0065da as the primary CTA accent. Type anchored in -apple-system at 64px / weight 600. Extracted automatically from https://biomejs.dev/ — rendered styles via getComputedStyle() + CSS custom properties (token-only values may not be painted)."
narrative: |
  biomejs.dev is built on a pure-white canvas (rgb(255, 255, 255)).
  The system uses rgb(0, 101, 218) as the high-saturation accent for primary actions.
  Moderately rounded CTAs (8px) — modern SaaS standard, neither sharp nor pill alongside -apple-system as the primary typeface.
  A restrained elevation system (2 distinct shadows) — shadows reserved for the few elements that must lift off the page.
  Motion is minimal — a few targeted transitions, no decorative animation.

colors:
  background: "#ffffff"
  surface-1: "#f5f6f8"
  surface-2: "#eceef2"
  ink: "#353841"
  ink-subtle: "#17181c"
  primary: "#0065da"
  on-primary: "#ffffff"
  primary-hover: "#8844ae"
  hairline: "#353841"
  primary-focus: "#101010"
  semantic-error: "#f53d7d"
  semantic-success: "#4fdf0c"
  semantic-warning: "#f5bb3d"

typography:
  display-xl:
    fontFamily: "-apple-system, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 64px
    fontWeight: 600
    lineHeight: 1.2
    letterSpacing: 0
  display-lg:
    fontFamily: "Helvetica Neue, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 64px
    fontWeight: 600
    lineHeight: 1.2
    letterSpacing: 0
  body:
    fontFamily: "Arial, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 13.3333px
    fontWeight: 400
    lineHeight: normal
    letterSpacing: 0
  body-sm:
    fontFamily: "Helvetica Neue, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 24px
    fontWeight: 600
    lineHeight: 1.75
    letterSpacing: 0
  caption:
    fontFamily: "Helvetica Neue, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 20px
    fontWeight: 400
    lineHeight: 1.75
    letterSpacing: 0
  button:
    fontFamily: "Helvetica Neue, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 14px
    fontWeight: 400
    lineHeight: 1.75
    letterSpacing: 0
  mono:
    fontFamily: "Helvetica Neue, 'SF Pro Display', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif"
    fontSize: 16.8px
    fontWeight: 400
    lineHeight: 1.75
    letterSpacing: 0

rounded:
  none: 0px
  xs: 4px
  sm: 8px
  md: 12px
  lg: 99.2px
  xl: 800px
  pill: 15984px

spacing:
  xxs: 2px
  xs: 4px
  sm: 8px
  md: 12px
  lg: 24px
  xl: 32px
  xxl: 56px

components:
  button-light--invert:
    backgroundColor: "{colors.on-primary}"
    textColor: "{colors.hairline}"
    typography: "{typography.button}"
    rounded: "{rounded.sm}"
    padding: 1px 8px 1px 12px
  button-primary-brand:
    backgroundColor: "{colors.primary}"
    textColor: "{colors.on-primary}"
    typography: "{typography.mono}"
    rounded: "{rounded.xs}"
    padding: 15px 20px
  button-outline:
    backgroundColor: "transparent"
    textColor: "{colors.ink-subtle}"
    typography: "{typography.mono}"
    rounded: "{rounded.xs}"
    padding: 15px 20px
  input-text-input:
    backgroundColor: "{colors.on-primary}"
    textColor: "{colors.ink-subtle}"
    typography: "{typography.mono}"
    rounded: "{rounded.sm}"
    padding: 0px 56px 0px 43.2px
  navigation-main-nav:
    backgroundColor: "{colors.surface-1}"
    typography: "{typography.mono}"
    rounded: "{rounded.none}"
    padding: 12px 24px
  code-block-inline-code--pre:
    backgroundColor: "{colors.surface-1}"
    textColor: "{colors.hairline}"
    typography: "{typography.button}"
    rounded: "{rounded.none}"

extracted_at: "2026-06-11T06:02:03.509Z"
completeness: 78
scoreVersion: "v2"

---

# Design System — biomejs.dev
> Extracted automatically by Prism from https://biomejs.dev
> Date: 2026-06-11
> Viewport: Desktop 1440x900 + Mobile 390x844
> Values are extracted, not hand-written: rendered styles via getComputedStyle() + colors declared in CSS custom properties (token-only values are marked `(token)` and may not be painted).


## 0. Design DNA

**Density**: moderate  |  **Motion**: expressive  |  **Weight**: heavy  |  **Aesthetic**: product-neutral

| Dimension | Value | Signal |
|---|---|---|
| Canvas | neutral | `#ffffff` |
| Type posture | sans-led (Roboto) | "One toolchain for your web pro" |
| Color assertion | dual-accent | #0065da |
| Whitespace | moderate | section rhythm 43px |
| Interaction | expressive | 0 keyframes, 3 transitions |
| Radius language | 8px-rounded | from token scale |

**Prism fingerprint**: `neutral-canvas · sans-display · dual-accent · 8px-rounded · expressive-motion`

> **🤖 TL;DR for AI agents** (read this first — saves you scanning the full doc):
>
> - **Canvas**: `rgb(255, 255, 255)` is the page background. Every component composits against this.
> - **Accent**: `rgb(0, 101, 218)` for primary CTAs ONLY. Never decorative.
> - **Body type**: 16px (token: `typography.body`). Default for ALL text not in a heading role.
> - **Section rhythm**: 43px between major bands. Card padding: 24px.
> - **Default radius**: 8px on buttons/inputs. Pills (`9999px`) only for icon-buttons or status chips.
>
> **Before generating UI**: import this DESIGN.md, scan §2 (Color Palette) + §4 (Components) + §10 (Agent Guide). Skip §11–12 unless extending.

## 1. Visual Theme & Atmosphere

**Signature:** a radial gradient glow in the hero. This is the brand's most recognizable visual — reproduce it, don't replace it with a generic card or flat panel.

biomejs.dev uses a pure-white canvas (`#ffffff`), letting typography, color and imagery carry the visual weight. 

Headlines are set in **-apple-system**, a sans-serif display face (the dominant type signature, e.g. "One toolchain for your web project" at 64px). Body text is set in **Roboto**. Headlines use weight 600 for confident, assertive presence — the brand wants to be heard. 

Body text reads in Dark Gray (`#353841`). **M Tricolor Blue** (`#0065da`) is the single high-saturation color in the system — it earns its presence only on interactive elements, making CTAs and links the unmistakable focal points against the otherwise neutral palette. Elevation comes from a small, deliberate set of shadows (2 distinct), each a multi-layer stack — several blurred layers at varying offsets — used sparingly rather than across the whole UI. 
Border radius varies from pill-shaped (fully rounded) to moderately rounded elements, creating visual rhythm. Motion design uses smooth easing curves for polished state transitions. 

**Key Characteristics:**
- Background: Pure White (`#ffffff`)
- Primary typeface: Helvetica Neue
- Primary text: Dark Gray (`#353841`)
- Accent: M Tricolor Blue (`#0065da`)
- Display: 64px weight 600
- Shadow system: 2 distinct elevation levels

## 2. Color Palette & Roles

### Background & Surface
- **Pure White** (`#ffffff`): Page background (primary)
- **Off-White** (`#f5f6f8`): Surface / elevated background
- **Off-White** (`#eceef2`): Surface / elevated background
- **Whitesmoke** (`#dddddd`): Surface / elevated background
- **Vibrant Yellow** (`#fceac5`): Surface / elevated background

### Text & Content
- **Dark Gray** (`#353841`): Primary body text
- **Pure Black** (`#000000`): Secondary text
- **#0000ee** (`#0000ee`): Secondary text
- **Near-Black** (`#17181c`): Secondary text
- **Near-Black** (`#111111`): Secondary text

### Accent & Interactive
- **M Tricolor Blue** (`#0065da`): Interactive / accent
- **Medium Gray** (`#788b94`): Interactive / accent
- **#8844ae** (`#8844ae`): Interactive / accent
- **#3b61b0** (`#3b61b0`): Interactive / accent
- **#984e4d** (`#984e4d`): Interactive / accent
- **Slate** (`#4d667b`): Interactive / accent
- **#a24848** (`#a24848`): Interactive / accent

### Border & Divider
- **Light Grey** (`#c0c2c7`): Borders / dividers

### Full Extracted Palette
**42 colors rendered on the page** + **29** more declared in design tokens (CSS custom properties — not necessarily painted). (18 categorized above + 53 additional below.)
Rendered values are read via `getComputedStyle()`; token values come from CSS variable declarations. Third-party logo colors are filtered out.

- `#403f53` — Dark Gray
- `#5d6376` — Dim Gray
- `#096e72` — #096e72
- `#aa0982` — #aa0982
- `#3a688f` — #3a688f
- `#b23834` — #b23834
- `#3cb371` — #3cb371
- `#cd5c5c` — Terracotta
- `#282c34` — Charcoal
- `#abb2bf` — Silver
- `#ff6347` — Coral
- `#90ee90` — Mint
- `#f5bb3d` — #f5bb3d
- `#edd1fa` — Soft Pink
- `#bb3df5` — #bb3df5
- `#defbd0` — Beige
- `#4fdf0c` — #4fdf0c
- `#fad1df` — Soft Pink
- `#f53d7d` — Warm Rose
- `#cfe6fc` — #cfe6fc
- `#3d99f5` — Ring Blue
- `rgba(37, 175, 244, 0.1)` — Translucent Sky Bright (10%)
- `#24272f` — Warm Brown
- `#545861` — Slate
- `#dadadc` — Whitesmoke *(token)*
- `#f6f7f9` — Off-White *(token)*
- `#27272a` — Near-Black *(token)*
- `#fff065` — #fff065 *(token)*
- `#ffdc1c` — Gold *(token)*
- `#393939` — Charcoal *(token)*
- `#0e0e10` — Near-Black *(token)*
- `#93a1a1` — Cool Gray *(token)*
- *…+21 more in `raw-css.json` (`desktop.allColors`).*

### CSS Custom Properties (Design Tokens)

**Success**
- `--sl-color-green`: `hsl(101, 90%, 46%)`
- `--sl-color-green-low`: `hsl(101, 85%, 90%)`
- `--sl-color-green-high`: `hsl(101, 80%, 22%)`

**Border Radius Token**
- `--pagefind-ui-border-radius`: `8px`
- `--pagefind-ui-image-border-radius`: `8px`
- `--unit-border-radius`: `4px`

**Background**
- `--sl-color-bg-inline-code`: `#eceef2`
- `--sl-color-bg-sidebar`: `#ffffff`
- `--sl-color-bg`: `#ffffff`
- `--sl-color-bg-nav`: `#f5f6f8`

**Z-Index Token**
- `--sl-z-index-menu`: `5`
- `--sl-z-index-skiplink`: `20`
- `--sl-z-index-navbar`: `10`
- `--sl-z-index-toc`: `4`

**Error / Destructive**
- `--sl-color-red`: `hsl(339, 90%, 60%)`
- `--sl-color-red-low`: `hsl(339, 80%, 90%)`
- `--sl-color-red-high`: `hsl(339, 80%, 30%)`

**Spacing Token**
- `--sl-content-gap-y`: `1rem`
- `--sl-nav-gap`: `1.5rem`

**Text Color**
- `--sl-color-text-invert`: `#ffffff`
- `--sl-color-text-accent`: `#0065da`
- `--sl-color-text`: `#353841`

**Primary Brand Color**
- `--sl-color-accent-low`: `#c2d9fa`
- `--sl-color-accent-high`: `#093066`
- `--sl-color-accent`: `#0065da`

**Shadow Token**
- `--sl-shadow-sm`: `0px 1px 1px hsla(0, 0%, 0%, .06), 0px 2px 1px hsla(0, 0%, 0%, .06)`

**Other tokens**
- `--sl-color-orange`: `hsl(41, 90%, 60%)`
- `--sl-badge-tip-bg`: `hsl(281, 90%, 30%)`
- `--sl-color-hairline-shade`: `#eceef2`
- `--sl-badge-note-bg`: `hsl(210, 80%, 30%)`
- `--ec-frm-inlBtnBgHoverOrFocusOpa`: `0.2`
- `--sl-text-h1`: `2.625rem`
- `--sl-text-h2`: `2.1875rem`
- `--sl-text-4xl`: `2.1875rem`

## 3. Typography Rules

### Font Families
- **Primary**: `-apple-system`
- **Secondary**: `ui-monospace`

### Typography Hierarchy

| Role | Font | Size | Weight | Line Height | Letter Spacing | Notes |
|------|------|------|--------|-------------|----------------|-------|
| Display Hero | -apple-system | 64px | 600 | 1.2 | normal | Main headline (h1) |
| Section Heading | Helvetica Neue | 64px | 600 | 1.2 | normal | Section titles (h1) |
| Link Large | Helvetica Neue | 24px | 600 | 1.75 | normal | Link (24px) — Decoration: none |
| Caption / Badge | Helvetica Neue | 20px | 400 | 1.75 | normal | small text (20px) |
| Input Large | Helvetica Neue | 16.8px | 400 | 1.75 | normal | Form input (16.8px) |
| Card Title | Helvetica Neue | 16px | 400 | 1.75 | normal | Card headings |
| Link Large | Helvetica Neue | 16px | 500 | 1.75 | normal | Link (16px) — Decoration: none |
| Link Large | Helvetica Neue | 16px | 600 | 1.75 | normal | Link (16px) — Decoration: none |
| Caption | Helvetica Neue | 14.4px | 500 | 1.65 | 0.200085px | Image caption, helper text |
| Button | Helvetica Neue | 14px | 400 | 1.75 | normal | Button label (14px) |
| Button | Arial | 13.3333px | 400 | normal | normal | Button label (13.3333px) |

### Full Font Size Scale

Sizes detected in the design (descending): `64px`, `40px`, `31.99px`, `24px`, `20px`, `16.80px`, `16px`, `14.40px`, `14px`, `13.33px`, `13px`, `12px`, `11.20px`

> 5 size(s) detected outside the sampled hierarchy (40px, 31.992px, 13px, 12px, 11.2px). These appear on elements not in the sampled set — likely additional display sizes, marketing-section overrides, or third-party-widget styles.

## 4. Component Stylings

### Buttons

**Light / Invert**
- Background: `#ffffff` `{colors.on-primary}`
- Text: `#353841` `{colors.hairline}`
- Padding: 1px 8px 1px 12px
- Radius: 8px
- Border: 1px solid rgb(192, 194, 199)
- Font: 14px weight 400
- Use: Bright CTA on dark sections
- Hover: color: `#17181c`, border: `1px solid rgb(53, 56, 65)`, borderColor: `#353841`
- Focus: outline: `rgb(16, 16, 16) auto 1px`

**Primary Brand**
- Background: `#0065da` `{colors.primary}`
- Text: `#ffffff` `{colors.on-primary}`
- Padding: 15px 20px
- Radius: 4.8px
- Border: 1px solid rgb(0, 101, 218)
- Font: 16px weight 400
- Use: Primary CTA / brand action
- Hover: color: `#17181c`, border: `1px solid rgb(53, 56, 65)`, borderColor: `#353841`
- Focus: outline: `rgb(16, 16, 16) auto 1px`

**Outline**
- Background: `transparent`
- Text: `#17181c` `{colors.ink-subtle}`
- Padding: 15px 20px
- Radius: 4.8px
- Border: 1px solid rgb(23, 24, 28)
- Font: 16px weight 400
- Use: Secondary action with border
- Hover: color: `#17181c`, border: `1px solid rgb(53, 56, 65)`, borderColor: `#353841`
- Focus: outline: `rgb(16, 16, 16) auto 1px`

**Pill**
- Background: `#0065da` `{colors.primary}`
- Text: `#ffffff` `{colors.on-primary}`
- Padding: 15px 20px
- Radius: 9999px
- Border: 1px solid rgb(0, 101, 218)
- Font: 16px weight 400
- Use: Status pills, tags, chips
- Hover: color: `#17181c`, border: `1px solid rgb(53, 56, 65)`, borderColor: `#353841`
- Focus: outline: `rgb(16, 16, 16) auto 1px`

### Inputs & Forms

**Text Input**
- Background: `#ffffff` `{colors.on-primary}`
- Text: `#17181c` `{colors.ink-subtle}`
- Padding: 0px 56px 0px 43.2px
- Radius: 8px
- Border: 1px solid rgb(192, 194, 199)
- Font: 16.8px weight 400
- Use: Text fields, search inputs

### Navigation

**Main Nav**
- Background: `#f5f6f8` `{colors.surface-1}`
- Padding: 12px 24px
- Radius: none
- Font: 16px weight 400
- Use: Fixed/sticky flex nav — N/A items

### Code Blocks

**Inline Code / Pre**
- Background: `#f5f6f8` `{colors.surface-1}`
- Text: `#353841` `{colors.hairline}`
- Padding: 0px
- Radius: 1px
- Font: 14.4px weight 400 — monospace
- Use: Code samples, CLI commands, syntax highlighting blocks


## 4b. Component Behaviors (State Matrix)

### Interaction State Narrative

- **Button**:
  - **hover:** text #353841 → #17181c, border changes

*State transitions extracted via Playwright simulation — exact values in the YAML matrix below.*

```yaml
component-behaviors:
  button:
    default:
      bg: "rgb(255, 255, 255)"
      fg: "rgb(53, 56, 65)"
      border: "1px solid rgb(192, 194, 199)"
    hover:
      bg: "transparent"
      fg: "rgb(23, 24, 28)"
      border: "1px solid rgb(53, 56, 65)"
    focus:
      bg: "transparent"
      fg: "inherit"
  input:
    default:
      bg: "rgb(255, 255, 255)"
      fg: "rgb(23, 24, 28)"
      border: "1px solid rgb(192, 194, 199)"
  link:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(0, 0, 238)"
  card:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(53, 56, 65)"
  navLink:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(0, 101, 218)"
  badge:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(53, 56, 65)"
```

**Agent usage**: Validate generated components against this matrix. If your output's `:hover` state changes properties not listed here, you are off-brand.


## 4c. Component Vocabulary (Closed System)

*This brand uses ONLY the following component vocabulary. Introducing new variants without justification breaks the system's tonal coherence.*

### Buttons
- **4 shape(s)** in this system: `Light / Invert`, `Primary Brand`, `Outline`, `Pill`
- **DO NOT introduce new buttons variants** without justification

### Inputs & Forms
- **1 shape(s)** in this system: `Text Input`
- **DO NOT introduce new inputs & forms variants** without justification

### Navigation
- **1 shape(s)** in this system: `Main Nav`
- **DO NOT introduce new navigation variants** without justification

### Code Blocks
- **1 shape(s)** in this system: `Inline Code / Pre`
- **DO NOT introduce new code blocks variants** without justification

## 5. Layout Principles

### Layout Type
**top-nav + content**

### Grid
Single column, centered content

### Max Width
67.5rem

### Spacing System
Compact spacing — information density prioritized

| Token | Value |
|-------|-------|
| xxs | 2px |
| xs | 4px |
| sm | 8px |
| md | 12px |
| base | 16px |
| lg | 24px |
| xl | 32px |
| 2xl | 43px |
| 3xl | 56px |

### Border Radius Scale
| Name | Value | Use |
|------|-------|-----|
| None | 0px | No rounding |
| Xs | 4px | Tiny corners (badges, micro elements) |
| Sm | 8px | Buttons, inputs, small elements |
| Md | 12px | Cards, containers |
| Lg | 99.2px | Large rounded elements, pill segments |
| Xl | 800px | Category strips, featured containers |
| Full | 15984px | Pills, avatars, circular elements |

### Shape Language

| Component | Border Radius |
|-----------|---------------|
| Buttons | `8px` |
| Inputs & Forms | `8px` |
| Navigation | `none` |
| Code Blocks | `1px` |
| Page Body | `0px` |
| Primary Input | `8px` |

**Shape Personality**: Moderate Rounding — Medium corners (4–12px). Modern SaaS standard, neither sharp nor pill.

**Full Radius Spectrum**: 0px, 1px, 3.2px, 4px, 4.8px, 8px, 9.6px, 12px (from `allBorderRadii` scan)


## 5b. Spacing Rhythm Names

**Measured section padding**: bands use ~106px internal vertical padding (up to 106px) — **very airy / premium**. (Distinct from the gap *between* sections above.) Reproduce this generous vertical breathing room; cramped spacing is the #1 tell of a cheap clone.

*Named spacing tokens with explicit use cases. Use these names in YOUR code instead of raw pixels for consistency.*

| Name | Value | Use case |
|------|-------|----------|
| **hero** | `56px` | Top/bottom of full-bleed hero sections |
| **section** | `32px` | Between major bands (color change, content shift) |
| **subsection** | `24px` | Within a section, between content groups |
| **card** | `12px` | Card padding, list-item spacing |
| **compact** | `8px` | Form fields, tight clusters, badge padding |
| **micro** | `4px` | Icon-text gap, tag inner padding |

**Agent rule**: NEVER hardcode raw pixel values for spacing in generated UI. Always reference these named tokens (`spacing-rhythm.section`, etc.).

## 5c. Widget & Structure Library

Structural patterns extracted from the page DOM — these are the **blueprints** an agent should follow to reproduce the page architecture (not just CSS values).

**4/8 structural patterns detected.**

### Hero Pattern

- **Composition:** split-left-text — Split layout, text-left/media-right — heading + body in left column, image/illustration in right column. Common for product showcases.
- **Viewport coverage:** 505px tall (not full-viewport)
- **Heading:** "One toolchain for your web project" — 64px left-aligned
- **Media:** present, positioned right
- **CTAs:** 2 (primary: "Get started")
- **Clone instruction:** Reproduce the **split-left-text** layout. Use the heading font-size token at the documented size. Place media right of text.

### Navigation Pattern

- **Position:** fixed (stays visible during scroll)
- **Layout:** logo-left-links-left — Logo and links both on the left (CTAs typically right)
- **Height:** 64px
- **Logo:** ✓ present
- **Nav links:** 12 primary items
- **CTAs in nav:** 0 (no buttons — links only)
- **Search:** ✓ search input visible in nav
- **Clone instruction:** Build a fixed logo left links left navigation. Link-only — no button styling needed.

### Card Grid Pattern

- **Card count:** 12 cards detected
- **Columns (desktop):** 1-up grid
- **Card dimensions:** 1080×571px (aspect 1.89:1)
- **Gap:** 112px between cards
- **Content:** ✗ no image
- **Clone instruction:** Build a 1-column grid (desktop) with cards at ~1.89:1 aspect ratio. Text/icon-only cards (no photography).

### Footer Pattern

- **Columns:** 1
- **Links:** 0 total
- **Height:** 72px
- **Includes:** ✗ no newsletter | ✗ no social |  
- **Clone instruction:** Build a 1-column footer with ~0 links per column.

## 6. Depth & Elevation

| Level | Treatment | Use |
|-------|-----------|-----|
| Flat (Level 0) | No shadow | Page background, content blocks |
| Layered (Level 1) | <br>`rgba(0, 0, 0, 0.01) 0px 25px 7px 0px`,<br>`rgba(0, 0, 0, 0.03) 0px 16px 6px 0px`,<br>`rgba(22, 24, 29, 0.08) 0px 9px 5px 0px`,<br>`rgba(0, 0, 0, 0.16) 0px 4px 4px 0px`,<br>`rgba(0, 0, 0, 0.04) 0px 4px 2px 0px` | Cards, elevated surfaces |
| Layered (Level 2) | <br>`rgba(0, 0, 0, 0.06) 0px 1px 1px 0px`,<br>`rgba(0, 0, 0, 0.06) 0px 2px 1px 0px` | Cards, elevated surfaces |

**Shadow Philosophy**: Multi-layered shadow system creating natural, atmospheric depth. Each shadow level combines multiple layers for realistic elevation.

## 7. Motion & Interaction

### Dominant Easing Curves

| Curve | Semantic Name |
|-------|---------------|
| `cubic-bezier(0.25,0.46,0.45,0.94)` | Quad Out — Smooth Ease |
| `ease-in` | Ease In — Accelerating |
| `ease` | CSS ease — Default |

### Duration Scale

| Value | Tier | Typical Use |
|-------|------|-------------|
| `100ms` | Fast | Hover states, micro-interactions |
| `200ms` | Normal | Panel open/close, navigation |

### Copy-Paste Transition Snippets

**Opacity**
```css
transition: opacity 0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94), background 0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94), border-color...;
```

**All Props**
```css
transition: width 0.1s ease-in;
```

### Motion Fingerprint

- **Speed Character**: Balanced Pacing (median duration: `200ms`)
- **Dominant Easing**: quad ease-out (smooth)

> This design moves with balanced pacing timing using quad ease-out (smooth), creating a UI that feels natural and fluid.

## 8. Do's and Don'ts

### Do
- Use Helvetica Neue as the primary typeface — it defines the brand personality
- Keep font weights between 400-600 — the system uses a narrow weight range for subtle hierarchy
- 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 M Tricolor Blue (`#0065da`) as the primary accent — it's the brand's signature interactive color
- Use small 4.8px radius for buttons — this design system uses subtle rounding, not pill shapes
- Style form inputs with a `1px solid rgb(192, 194, 199)` border — use border-based inputs, not floating labels or underline-only
- Respect the 4px–32px spacing range — the design uses a wide scale for visual breathing room
- Build the hero as a split layout with media on the left — text and visual share equal weight
- Include exactly 2 CTAs in the hero (primary + secondary) — this design pattern is multi-action, not single-purpose
- Make the navigation fixed — it stays visible during scroll, signaling content depth
- Include a search input directly in the nav — discoverability is a primary UX value here

### Don't
- Don't substitute with generic sans-serif or serif — the custom font carries the brand
- Don't use weight 700 (bold) or above — 600 is the maximum weight in this system
- 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 over-round buttons with pill or large radius — the system uses restrained, sharp-ish corners
- Don't remove the input border — the border is the primary affordance indicator for form fields
- Don't put a CTA button in the nav — this design uses links only at the top
- Don't over-build the footer — this design keeps it minimal (1 cols, 0 links)


## 7b. Enforceable Brand Rules

*Structured Do/Don't with reasoning and validation tests. Agents can programmatically verify generated UI.*

```yaml
rules:
  - id: brand-canvas-001
    type: do
    rule: "Always use the page background `rgb(255, 255, 255)` as the base canvas"
    why: "Every component is designed to composit against this exact tone"
    test: "document.body.style.backgroundColor === 'rgb(255, 255, 255)'"
  - id: brand-accent-001
    type: do
    rule: "Reserve `rgb(0, 101, 218)` for primary CTAs and brand-mark signals only"
    why: "Single chromatic assertion device — overuse dilutes meaning"
    test: "querySelectorAll('[style*=\"rgb(0, 101, 218)\"]').length <= 3 per fold"
```

## 9. Responsive Behavior

### Breakpoints
| Name | Width | Key Changes |
|------|-------|-------------|
| Mobile | 400px | Single column, compact spacing |
| Mobile | 480px | Single column, compact spacing |
| Mobile Large | 550px | Expanded mobile layout |
| Mobile Large | 600px | Expanded mobile layout |
| Mobile Large | 750px | Expanded mobile layout |
| Desktop | 1152px | Full feature layout |

### Token Diff — Desktop vs Mobile

| Element | Property | Desktop | Mobile |
|---------|----------|---------|--------|
| heading | font-size | `64px` | `29px` |
| heading | line-height | `76.8px` | `34.8px` |
| button | padding | `1px 8px 1px 12px` | `1px 6px` |
| button | font-size | `14px` | `20px` |
| button | width | `291.844px` | `32px` |
| card | width | `1080px` | `358px` |
| main | padding | `0px 0px 27px` | `0px 0px 25.32px` |

### Collapsing Strategy
- Headlines: 64px → 29px on mobile
- Container padding: 0px 0px 27px → 0px 0px 25.32px on mobile
- Navigation: horizontal links → hamburger menu on mobile
- Cards: multi-column → stacked vertical on mobile
- Footer: multi-column → stacked single column on mobile

### Touch Targets
- Buttons: 1px 8px 1px 12px padding
- Navigation: adequate spacing between items
- Interactive elements: minimum 44px touch target recommended

### Collapsing Narrative

How the structural patterns adapt from desktop to mobile (extracted from both viewport extractions):

- **Hero collapses split-left-text → centered** — the side-by-side layout stacks vertically, with media moving above the text.
- **Navigation collapses to hamburger** — 12 links visible on desktop, 1 on mobile (the rest hide behind a menu toggle).


## 7c. Visual Effects & Dynamic Behavior

*The live/dynamic layer beyond static CSS — reproduce these, not flat substitutes. This is often what separates a faithful clone from a wireframe.*

- **Mesh gradients** — 3 multi-stop organic color field(s) as background atmosphere.
- **Scroll-driven reveals** — content animates in on scroll (CSS scroll-timeline). Build fade/translate reveal-on-scroll for below-fold bands.

> **Motion fingerprint**: mesh gradients, CSS scroll-driven animations

## 9b. Visual Tone & Photography

**Tone:** Photography-driven

The site is dominated by photography (JPG/WebP). Photos carry the brand voice as much as the typography. Use authentic, brand-appropriate imagery — generic stock will degrade quality.

**Canonical Brand Image (OG):**
- https://biomejs.dev/img/og.png?v=2
  *This is the image shown when the site is shared on social media — represents the brand visual essence.*

**Hero Image (above-fold dominant visual):**
- Aspect: 4.1:1 (ultra-wide cinematic)
- Rendered size: 381×93px
- Alt text: "Biome, Toolchain of the web"
- *Use this aspect ratio + composition for your clone's hero — mimicking the proportion preserves the visual hierarchy.*

**Aspect Ratio Distribution:**
- Landscape (1.15–2.3): 0 (0%)
- Portrait (<0.87): 0 (0%)
- Square (0.87–1.15): 47 (92%)
- Ultra-wide (>2.3): 4 (8%)

**Media Format Mix:**
- WebP: 50 (optimized photo/illustration hybrid)
- SVG: 1 (icons, illustrations, decorative geometry)

**Average rendered image size:** 92×72px
**Above-fold image count:** 1 / 51

**Decorative Patterns Detected:**
- 1 multi-stop linear gradient (mesh-like, 3+ color stops) — the brand leans on rich color transitions for visual depth
- 3 radial gradients — circular color blooms used for spotlight/glow effects

**Clone instruction for decorative work:** This is a gradient-rich design — invest in multi-stop CSS gradients (3+ color stops), not solid backgrounds.

**Imagery Guidance for clones:**
- Source authentic photography (or licensed stock that matches the brand mood) — placeholders will visibly degrade the clone.
- Match the dominant aspect ratio (see above) so card grids and hero compositions hold.

## 10. Agent Prompt Guide

### Quick Reference
- Background: Pure White (`#ffffff`)
- Primary text: Dark Gray (`#353841`)
- Accent: M Tricolor Blue (`#0065da`)
- Border: Dark Gray (`#353841`)
- Font: Helvetica Neue
- Body: 16px weight 400

### Example Component Prompts
- "Create a hero section on Pure White background (#ffffff). Headline at 64px Helvetica Neue weight 600, line-height 1.2, color #353841."
- "Create the primary CTA button: `#0065da` background, `#ffffff` text, 4.8px border-radius, 15px 20px padding, 700 weight, Helvetica Neue font."
- "Design a card on `transparent` background. Border: none. Radius: 0px. Shadow: none. Padding: 0px."
- "Build navigation: sticky on `#ffffff`. Helvetica Neue 16px weight 400 for links."

### Iteration Guide
1. **Canvas**: Set the light canvas to Pure White (`#ffffff`) — every component is composited against this exact base.
2. **Typography**: All type in Helvetica Neue, weight range 400–600. Never exceed 600 — heavier weights break the brand's tonal restraint.
3. **Accent**: M Tricolor Blue (`#0065da`) — one accent, applied consistently to CTAs, active states, and links. Never introduce a second saturated color.
4. **Motion**: All transitions use `cubic-bezier(0.25,0.46,0.45,0.94)`. Never use linear for UI transitions — preserve the brand's easing personality.
5. **Shape**: CTAs at `8px`, cards at `0px`. Apply border-radius from the extracted scale only — don't invent intermediate values.
6. **Spacing**: Use the `--ca-space-*` token scale (4px–32px). All padding, margin, and gap values are multiples from this scale — no magic numbers.
7. **Tokens**: Import from §11 CSS Export (`--ca-*` vars). Never hardcode hex values — always reference a token so theming remains consistent.

## 11. CSS Design Tokens Raw Export

*Copy-paste ready `:root {}` block — all values extracted directly from the live site.*

```css
/* Colors */
:root {
  --ca-on-primary: #ffffff;
  --ca-surface-1: #f5f6f8;
  --ca-surface-2: #eceef2;
  --ca-hairline: #353841;
  --ca-ink-subtle: #17181c;
  --ca-primary: #0065da;
  --ca-primary-hover: #8844ae;
  --ca-primary-focus: #101010;
  --ca-semantic-error: #f53d7d;
  --ca-semantic-success: #4fdf0c;
  --ca-semantic-warning: #f5bb3d;
}

/* Typography */
:root {
  --ca-font-primary: "-apple-system", system-ui, sans-serif;
  --ca-text-display: 64px;
  --ca-text-heading: 64px;
  --ca-text-body: 13.3333px;
  --ca-text-small: 24px;
  --ca-text-caption: 20px;
  --ca-text-button: 14px;
  --ca-text-mono: 16.8px;
}

/* Spacing & Radius */
:root {
  --ca-space-xxs: 2px;
  --ca-space-xs: 4px;
  --ca-space-sm: 8px;
  --ca-space-md: 12px;
  --ca-space-base: 16px;
  --ca-space-lg: 24px;
  --ca-space-xl: 32px;
  --ca-space-2xl: 43px;
  --ca-space-3xl: 56px;
  --ca-radius-none: 0px;
  --ca-radius-xs: 4px;
  --ca-radius-sm: 8px;
  --ca-radius-md: 12px;
  --ca-radius-lg: 99.2px;
  --ca-radius-xl: 800px;
  --ca-radius-full: 15984px;
}
```


## 13. Page Structure Skeleton

*The actual layout the source site uses. Reproduce these sections in order to match the site structure.*

```yaml
page-skeleton:
  - section: hero
    tag: div
    classes: ["page", "sl-flex", "astro-nzfyskjk"]
    height: 6704px
    width: full-bleed
    layout: flex-column justify=normal
    children: 2
    bg-treatment: radial-gradient
    vertical-padding: ~38px
  - section: feature-section
    tag: main
    height: 6640px
    width: full-bleed
    layout: block
    children: 2
    padding: "0px 0px 27px"
  - section: feature-section
    tag: div
    classes: ["hero"]
    height: 505px
    width: 1080px
    layout: grid: 2-col gap=3%
    children: 3
    vertical-padding: ~106px (airy)
    padding: "106px 0px"
  - section: feature-section
    tag: div
    height: 6522px
    width: 1080px
    layout: block
    children: 6
    vertical-padding: ~106px (airy)
  - section: content-section
    tag: div
    classes: ["hero-code"]
    height: 814px
    width: 1080px
    layout: block
    children: 6
  - section: content-section
    tag: div
    classes: ["hero-code"]
    height: 681px
    width: 1080px
    layout: block
    children: 6
  - section: content-section
    tag: div
    classes: ["hero-code"]
    height: 280px
    width: 1080px
    layout: block
    children: 5
  - section: content-section
    tag: div
    classes: ["card-cnt"]
    height: 634px
    width: 1080px
    layout: block
    children: 1
  - section: unknown
    tag: div
    classes: ["installation-body"]
    height: 446px
    width: 1080px
    layout: flex-row justify=center
    children: 1
  - section: unknown
    tag: div
    classes: ["award"]
    height: 170px
    width: 1080px
    layout: flex-row justify=center
    children: 1
  - section: content-section
    tag: div
    classes: ["featured-users"]
    height: 678px
    width: 1080px
    layout: block
    children: 4
    padding: "0px 16px"
  - section: unknown
    tag: div
    classes: ["community"]
    height: 704px
    width: 1080px
    layout: block
    children: 4
  - section: unknown
    tag: div
    height: 164px
    width: 1080px
    layout: flex-row justify=center
    children: 1
    padding: "32px 0px 0px"
  - section: footer
    tag: div
    classes: ["footer-sponsors"]
    height: 108px
    width: 1080px
    layout: flex-column justify=normal
    children: 2
    padding: "8px 32px"
  - section: unknown
    tag: div
    classes: ["copyright"]
    height: 109px
    width: 1080px
    layout: flex-column justify=center
    children: 1
    vertical-padding: ~32px
    padding: "32px"
```

**Agent rule**: rebuild sections in this order (sorted by vertical position). Match the layout primitive (grid N-col / flex direction / block).


## 14. Copy Library (Real Content from Source)

*Actual text content extracted from the live page. Use these strings verbatim when reproducing the site — they carry the brand voice.*

```yaml
copy:
  section-headings:
    - "Format code like Prettier, save time"
  ctas:
    - "Search Ctrl K"
    - "Get started"
    - "View on GitHub"
    - "View all users"
  navigation:
    - "Biome"
    - "Discord"
    - "GitHub"
    - "Mastodon"
    - "Open Collective"
    - "YouTube"
    - "BlueSky"
    - "RSS"
    - "Docs"
    - "Enterprise"
```

**Agent rule**: reuse these exact strings when generating UI. Do NOT translate or rephrase — brand voice is preserved through the original wording.


## 15. Asset Inventory (Image Roles & Ratios)

*Image inventory classified by role and aspect ratio. When reproducing the site, allocate this number of assets per role.*

```yaml
assets:
  logo:
    count: 1
    avg-ratio: 4.22
    common-aspect: "~16:6 banner"
  thumbnail:
    count: 43
    avg-ratio: 1.00
    common-aspect: "~1:1 square"
    sample-alts:
      - "Astro logo"
      - "AWS logo"
      - "Canonical logo"
  icon:
    count: 2
    avg-ratio: 1.45
    common-aspect: "~1:1 square"
    sample-alts:
      - "arrow"
      - "arrow"
```

**Agent rule**: when generating placeholder images, match these counts and aspect ratios. Use neutral placeholder backgrounds for `product` (e.g. `#f5f5f5`), full-color photography hints for `hero` and `editorial`.


## 16. Component HTML Templates

*Suggested HTML markup for reproducing the key components — based on what was detected in the source DOM.*

### Button (primary action)
```html
<button class="btn btn-primary">
  Search
Ctrl
K
</button>
```
_Source pattern detected: padding `1px 8px 1px 12px` · radius `8px` · weight `400`_

### Generic Card
```html
<div class="card">
  <!-- content -->
</div>
```
_Source pattern detected: padding `0px` · radius `0px` · shadow `none`_

**Agent rule**: use these markup skeletons as the structural baseline. Apply tokens from §2-3 for visual styling.


## 17. Content Architecture & Resources (Links by Purpose)

*The page's links classified by purpose — the information architecture to reproduce. Categories, featured images, devices and projects are extracted from the rendered DOM, not guessed.*

**By purpose:** **nav** 7 · **cta** 1 · **docs** 4 · **blog** 3 · **social** 5 · **footer** 2 · **other** 9

**Primary actions (conversion path):**
- Primary call-to-action — "Get started" (the conversion path) → `https://biomejs.dev/guides/getting-started/`

**Projects / case studies detected** (clustered by URL + featured image):

*Guides* — medium confidence, 4 items:

| Title | Featured image | Link |
|---|---|---|
| Get started | — | https://biomejs.dev/guides/getting-started/ |
| Install with package manager | `arrow-right.IMLC3H30_Z1jrvaI.svg?dpl` (ar 1.45) | https://biomejs.dev/guides/getting-started/#installation |
| Integrate Biome in your editor | `arrow-right.IMLC3H30_Z1jrvaI.svg?dpl` (ar 1.45) | https://biomejs.dev/guides/editors/first-party-extensions/ |
| Docs | — | https://biomejs.dev/guides/getting-started |

*Biomejs* — medium confidence, 3 items:

| Title | Featured image | Link |
|---|---|---|
| GitHub | — | https://github.com/biomejs/biome |
| fast formatter | — | https://github.com/biomejs/biome/tree/main/benchmark#formatting |
| performant linter | — | https://github.com/biomejs/biome/tree/main/benchmark#linting |

**Signals:** 16/31 links carry a featured image · device mockups detected: laptop ×2 · dominant link roles: inline-link (11), content-card (8), navigation (7).


---
## Extraction Completeness: 78/100 (B)

| Category | Score | Max | Detail |
|----------|-------|-----|--------|
| Colors & Palette | 25 | 25 | 18 named colors |
| Typography | 20 | 20 | 11 roles defined |
| Components | 16 | 20 | 4 specs extracted |
| Motion & Interaction | 2 | 15 | No keyframes |
| CSS Custom Properties | 10 | 10 | 231 vars |
| Responsive Breakpoints | 5 | 5 | 6 breakpoints |
| Variable Fonts | 0 | 5 | None detected |

## 12. Known Gaps & Confidence

Explicit list of what this extraction could NOT capture. Agents should not invent values for these — either skip the feature or use the documented baseline + heuristic fallback.

*Auto-detected extraction limitations — understand before building:*

- **Sparse component extraction** — fewer than 5 component types detected. Highly dynamic sections (modals, datepickers, carousels) require interaction to render and are not captured in a static pass.

| Category | What's missing | Fallback strategy |
|----------|----------------|-------------------|
| **Keyframe animations** | No @keyframes declarations found (transitions only) | Use CSS transitions for state changes; avoid complex scroll-based animations |
| **Dark mode** | No dark-mode CSS variables or media queries detected | Light mode is canonical; do not generate dark-mode variants unless explicitly requested |

### Per-section confidence

| Section | Confidence | Reason |
|---------|------------|--------|
| §1 Visual Theme | High | Body bg extracted via getComputedStyle() |
| §2 Colors | High | 231 CSS vars (semantic naming requires ≥20 for high) |
| §3 Typography | High | 11 typography roles inferred |
| §4 Components | Medium | 4 component variants captured |
| §7 Motion | Medium | Transitions only |
| §8 Do's/Don'ts | High | 21 rules generated; design-decisions.json has evidence per rule |
| §9 Responsive | High | 6 breakpoints detected |
| §9b Photography | High | 51 images, hero present |

## 11.2 Measured Reality (CDP Engine)

Captured directly from Chrome's engine across **all 2444 rendered nodes** — not a sample. These are the values the page *actually paints*, weighted by how often they appear.

### Real Responsive Breakpoints
**11 breakpoints** read from the live `@media` rules (not guessed):
`400px` · `550px` · `600px` · `700px` · `750px` · `768px` · `900px` · `960px` · `970px` · `1080px` · `1200px`

### Measured Design Scale
**Type scale by usage** (× = paint count): `11.2px`×1201 · `14px`×662 · `16px`×419 · `14.4px`×55 · `24px`×30 · `13.3333px`×30 · `20px`×22 · `31.992px`×13

**Radius scale** (× = paint count): `800px`×32 · `3.2px`×20 · `12px`×15 · `50%`×15 · `1px`×10 · `4px`×7 · `4.8px`×4 · `99.2px`×4

**Weights** (× = paint count): `400`×2019 · `700`×293 · `500`×72 · `600`×59

**Layout gaps** (× = paint count): `16px`×17 · `12px`×15 · `4px`×8 · `19.2px`×8 · `24px`×7 · `8px`×7 · `9.6px`×4 · `32px`×2

**Elevation (real shadows)**:
```css
rgba(0, 0, 0, 0.06) 0px 1px 1px 0px, rgba(0, 0, 0, 0.06) 0px 2px 1px 0px
```

### Provenance — measured styles on key elements
Read from the live CSSOM (includes runtime-injected CSS). This is *what actually styles the page*, by element:

```css
body { font-family:var(--__sl-font); color:var(--sl-color-text); background-color:var(--sl-color-bg) }
header { background-color:var(--sl-color-bg-nav) }
h1 { font-size:clamp(var(--sl-text-3xl),calc(.25rem + 5vw),var(--sl-text-6xl)); font-weight:600; color:var(--sl-color-white) }
h2 { font-size:var(--sl-text-h2) }
h2 { font-size:var(--sl-markdown-text-h2) }
button { gap:.5rem; background-color:transparent; color:var(--sl-color-gray-1); font-size:var(--sl-text-xl) }
@media (min-width: 50rem) button { border-radius:.5rem; background-color:var(--sl-color-black); color:var(--sl-color-gray-2); font-size:var(--sl-text-sm) }
input { background-color:var(--pagefind-ui-background); border-radius:var(--pagefind-ui-border-radius); font-size:calc(21px * var(--pagefind-ui-scale)); font-weight:700 }
input { color:var(--sl-color-white); font-weight:400 }
```

> Selectors normalised to their semantic element — source class names are often build-hashed (`.bgDIHX`) and not reusable. The declarations + CSS vars are the transferable part.

---
*Generated by Prism — automated Playwright extraction + design analysis.*
*Source: https://biomejs.dev | 2026-06-11T06:02:03.634Z*
*Values extracted via getComputedStyle() (rendered) + CSS custom properties (tokens, marked `(token)`). Token-only values may not be painted — verify against the live site before shipping.*