posthog.com

DESIGN.md

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

---
version: alpha
name: posthog.com
description: "Light product system built on #eeefe9 with #cd8407 as the primary CTA accent. Type anchored in IBM Plex Sans Variable at 24px / weight 800. Extracted automatically from https://posthog.com/ — every value from getComputedStyle(), no approximation."
narrative: |
  posthog.com is built on a warm, off-white canvas (rgb(238, 239, 233)).
  The system uses rgb(205, 132, 7) as the high-saturation accent for primary actions.
  Crisp CTAs (4px radius) reinforce a precise, technical aesthetic alongside IBM Plex Sans Variable as the primary typeface.

colors:
  background: "#eeefe9"
  surface-1: "#e5e7e0"
  surface-2: "#ffffff"
  ink-muted: "#23251d"
  ink-subtle: "#23251d"
  primary: "#cd8407"
  on-primary: "#111111"
  primary-hover: "#b17816"
  hairline: "#bfc1b7"

typography:
  display-xl:
    fontFamily: "IBM Plex Sans Variable"
    fontSize: 24px
    fontWeight: 800
    lineHeight: 1.33
    letterSpacing: -0.6px
  display-md:
    fontFamily: "IBM Plex Sans Variable"
    fontSize: 19.2857px
    fontWeight: 600
    lineHeight: 1.56
    letterSpacing: -0.482143px
  body:
    fontFamily: "IBM Plex Sans Variable"
    fontSize: 16px
    fontWeight: 400
    lineHeight: 1.5
    letterSpacing: 0
  body-sm:
    fontFamily: "IBM Plex Sans Variable"
    fontSize: 15px
    fontWeight: 600
    lineHeight: 1.71
    letterSpacing: 0
  button:
    fontFamily: "IBM Plex Sans Variable"
    fontSize: 13px
    fontWeight: 500
    lineHeight: 1
    letterSpacing: 0

rounded:
  none: 0px
  xs: 4px
  sm: 8px
  md: 8px
  lg: 8px
  xl: 8px
  xxl: 24px
  pill: 9999px

spacing:
  xxs: 2px
  xs: 4px
  sm: 8px
  md: 16px
  lg: 24px
  xl: 32px
  xxl: 64px
  section: 80px

components:
  button-ghost:
    backgroundColor: "transparent"
    textColor: "{colors.ink-subtle}"
    typography: "{typography.button}"
    rounded: "{rounded.xs}"
    padding: 2px 8px
  button-primary-brand:
    backgroundColor: "{colors.primary}"
    textColor: "{colors.ink-subtle}"
    typography: "{typography.body}"
    rounded: "{rounded.xs}"
  button-ghost:
    backgroundColor: "transparent"
    textColor: "{colors.ink-subtle}"
    typography: "{typography.button}"
    rounded: "{rounded.xs}"
    padding: 2px 4px
  card-standard-card:
    backgroundColor: "transparent"
    typography: "{typography.body}"
    rounded: "{rounded.none}"
    padding: 16px 32px
  navigation-main-nav:
    backgroundColor: "transparent"
    typography: "{typography.body}"
    rounded: "{rounded.none}"
  tab-ghost-tab:
    backgroundColor: "transparent"
    textColor: "#374151"
    typography: "{typography.body-sm}"
    rounded: "{rounded.none}"
  tab-pill-tab:
    backgroundColor: "#2f80fa"
    textColor: "{colors.surface-2}"
    typography: "{typography.body-sm}"
    rounded: "{rounded.xs}"
    padding: 10px 12px
  code-block-inline-code--pre:
    backgroundColor: "transparent"
    textColor: "transparent"
    typography: "{typography.body-sm}"
    rounded: "{rounded.xs}"
  alert-alert-banner:
    backgroundColor: "{colors.surface-2}"
    textColor: "#4d4f46"
    typography: "{typography.body}"
    rounded: "{rounded.xs}"
    padding: 16px

extracted_at: "2026-05-30T20:39:41.700Z"
completeness: 89
scoreVersion: "v2"

---

# Design System — posthog.com
> Extracted automatically by Clone Architect from https://posthog.com
> Date: 2026-05-30
> Viewport: Desktop 1440x900 + Mobile 390x844
> Every value in this file comes from real getComputedStyle() — no approximation.

> **🤖 TL;DR for AI agents** (read this first — saves you scanning the full doc):
>
> - **Canvas**: `rgb(238, 239, 233)` is the page background. Every component composits against this.
> - **Accent**: `rgb(205, 132, 7)` for primary CTAs ONLY. Never decorative.
> - **Body type**: 16px (token: `typography.body`). Default for ALL text not in a heading role.
> - **Section rhythm**: 48px 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

posthog.com's canvas is a warm, intentionally-tinted surface (`#eeefe9`) — a refusal of the default white that immediately signals editorial intent. This isn't sterility, it's an invitation to read. 

Typography is anchored in **IBM Plex Sans Variable**. Headlines use weight 800 for confident, assertive presence — the brand wants to be heard. Negative letter-spacing at display sizes (-0.6px at 24px) compresses headlines into engineered blocks, dense and precise. 

Body text reads in Pure Black (`#000000`) (contrast ratio 93.3:1, well above WCAG AA). **#cd8407** (`#cd8407`) 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 is built from multi-layer shadow stacks — each level combines several blurred layers at varying offsets to simulate the way light actually falls on stacked surfaces, not the simulated drop-shadow of cheap interfaces. 
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. The site uses a variable font with WGHT axes, enabling precise weight/width control across the type hierarchy. 

**Key Characteristics:**
- Background: Light Gray (`#eeefe9`)
- Primary typeface: Source Code Pro
- Accent: #cd8407 (`#cd8407`)
- Display: 24px weight 800, letter-spacing -0.6px
- Shadow system: 2 distinct elevation levels
- Custom fonts loaded: Source Code Pro, IBM Plex Sans Variable, Fairytale, Computer Modern, Squeak, Open Runde, Charter

## 2. Color Palette & Roles

### Background & Surface
- **Light Gray** (`#eeefe9`): Page background (primary)
- **Translucent Light Gray (75%)** (`rgba(229, 231, 224, 0.75)`): Surface / elevated background
- **Pure White** (`#ffffff`): Surface / elevated background
- **Cream** (`#fdfdf8`): Surface / elevated background
- **Warm Cream** (`#f3f4f0`): Surface / elevated background

### Text & Content
- **Pure Black** (`#000000`): Primary body text
- **Warm Brown** (`#23251d`): Secondary text
- **Deep Navy** (`#111827`): Secondary text
- **#0500ff** (`#0500ff`): Secondary text
- **Near Black** (`#1f1f1f`): Secondary text

### Accent & Interactive
- **#cd8407** (`#cd8407`): Interactive / accent
- **Honey** (`#b17816`): Interactive / accent
- **#eb9d2a** (`#eb9d2a`): Interactive / accent
- **#e1d7c2** (`#e1d7c2`): Interactive / accent
- **Dark Gray** (`#374151`): Interactive / accent
- **#1d4aff** (`#1d4aff`): Interactive / accent
- **#f9bd2b** (`#f9bd2b`): Interactive / accent

### Border & Divider
- **Silver** (`#bfc1b7`): Borders / dividers
- **Silver** (`#b6b7af`): Borders / dividers
- **Translucent Silver (50%)** (`rgba(210, 211, 204, 0.5)`): Borders / dividers
- **Silver** (`#d0d1c9`): Borders / dividers
- **#dad7d4** (`#dad7d4`): Borders / dividers

### Full Extracted Palette
256 distinct colors detected on the live page (22 categorized above + 234 additional below). Every value is a real `getComputedStyle()` color — no approximation.

- `#65675e` — Dim Gray
- `#4d4f46` — Dark Gray
- `#9ea096` — Cool Gray
- `#73756b` — Stone
- `#f54e00` — Bright Orange
- `#2f80fa` — Ring Blue
- `#b62ad9` — #b62ad9
- `#36c46f` — #36c46f
- `#f7a501` — Amber
- `#6aa84f` — #6aa84f
- `#30abc6` — #30abc6
- `#29dbbb` — #29dbbb
- `#ff5a00` — Bright Orange
- `#fffefe` — Pure White
- `#4b73ff` — Ring Blue
- `#ff66f4` — Magenta
- `#ff0105` — Red
- `#fe7b02` — #fe7b02
- `#20c178` — Emerald
- `#40ba9b` — #40ba9b
- `#ab81e9` — #ab81e9
- `#00ba97` — Emerald
- `#128414` — Forest Green
- `#0079ff` — #0079ff
- `#00e1ff` — #00e1ff
- `#3ecf8e` — #3ecf8e
- `#f7d046` — #f7d046
- `#f2a73b` — #f2a73b
- `#ee792f` — Coral
- `#eb5829` — Vermillion
- `#ea3326` — M Tricolor Red
- `#1f40ec` — #1f40ec
- *…+202 more in `raw-css.json` (`desktop.allColors`).*

### CSS Custom Properties (Design Tokens)

**Shadow Token**
- `--tw-ring-offset-shadow`: `0 0 #0000`
- `--tw-ring-shadow`: `0 0 #0000`
- `--tw-shadow`: `0 0 #0000`
- `--tw-shadow-colored`: `0 0 #0000`

**Spacing Token**
- `--tw-numeric-spacing`: ``
- `--tw-border-spacing-x`: `0`
- `--tw-border-spacing-y`: `0`
- `--viewport-padding`: `25px`

**Other tokens**
- `--squeak-button-color`: `245,78,0`
- `--swiper-pagination-bullet-inactive-color`: `#000`
- `--squeak-primary-color`: `0,0,0`
- `--tw-ring-color`: `rgba(59,130,246,.5)`
- `--swiper-theme-color`: `#007aff`
- `--swiper-pagination-color`: `#f54e00`
- `--tw-ring-offset-color`: `#fff`
- `--tw-text-opacity`: `1`

## 3. Typography Rules

### Font Families
- **Primary**: `IBM Plex Sans Variable`
- **Secondary**: `Source Code Pro`
- **Font 3**: `Fairytale`
- **Font 4**: `Computer Modern`
- **Font 5**: `Squeak`

### Custom Fonts Loaded
- **Source Code Pro** weight 400 (normal)
- **IBM Plex Sans Variable** weight 100 700 (normal)
- **Fairytale** weight 400 (normal)
- **Computer Modern** weight 400 (normal)
- **Squeak** weight 700 (normal)
- **Open Runde** weight 400 (normal)
- **Open Runde** weight 500 (normal)
- **Open Runde** weight 600 (normal)
- **Open Runde** weight 700 (normal)
- **Charter** weight 400 (normal)
- **Charter** weight 700 (normal)
- **swiper-icons** weight 400 (normal)

### Typography Hierarchy

| Role | Font | Size | Weight | Line Height | Letter Spacing | Notes |
|------|------|------|--------|-------------|----------------|-------|
| Display Hero | IBM Plex Sans Variable | 24px | 800 | 1.33 | -0.6px | Main headline (h1) |
| Sub-heading | IBM Plex Sans Variable | 19.2857px | 600 | 1.56 | -0.482143px | Third-level heading (h3) |
| Body | IBM Plex Sans Variable | 16px | 400 | 1.5 | normal | Standard reading text |
| Card Title | IBM Plex Sans Variable | 15px | 400 | 1.71 | normal | Card headings |
| Link | IBM Plex Sans Variable | 15px | 600 | 1.71 | normal | Link (15px) — Decoration: none |
| Button | IBM Plex Sans Variable | 13px | 500 | 1 | normal | Button label (13px) |
| Button | IBM Plex Sans Variable | 13px | 400 | 1.5 | normal | Button label (13px) |

### Full Font Size Scale

Sizes detected in the design (descending): `36px`, `24px`, `21.43px`, `20px`, `19.29px`, `18px`, `16px`, `15px`, `14px`, `13px`, `12px`

> 6 size(s) detected outside the sampled hierarchy (36px, 21.4286px, 20px, 18px, 14px, 12px). These appear on elements not in the sampled set — likely additional display sizes, marketing-section overrides, or third-party-widget styles.

### OpenType & Variable Font Features

**Variable font axes:**
- WGHT axis

## 4. Component Stylings

### Buttons

**Ghost**
- Background: `transparent`
- Text: `#23251d` `{colors.ink-subtle}`
- Padding: 2px 8px
- Radius: 4px
- Font: 13px weight 500
- Use: Subtle action, toolbar, nav button
- Focus: backgroundColor: `rgb(200, 202, 193)`

**Primary Brand**
- Background: `#cd8407` `{colors.primary}`
- Text: `#23251d` `{colors.ink-subtle}`
- Padding: 0px
- Radius: 6px
- Border: 1px solid rgb(177, 120, 22)
- Font: 16px weight 400
- Use: Primary CTA / brand action
- Focus: backgroundColor: `rgb(200, 202, 193)`

**Ghost**
- Background: `transparent`
- Text: `#23251d` `{colors.ink-subtle}`
- Padding: 2px 4px
- Radius: 4px
- Border: 1px solid rgba(0, 0, 0, 0)
- Font: 13px weight 400
- Use: Subtle action, toolbar, nav button
- Focus: backgroundColor: `rgb(200, 202, 193)`

**Light / Invert**
- Background: `#e5e7e0` `{colors.surface-1}`
- Text: `#65675e`
- Padding: 4px 6px
- Radius: 4px
- Font: 16px weight 400
- Use: Bright CTA on dark sections
- Focus: backgroundColor: `rgb(200, 202, 193)`

**Subtle**
- Background: `rgba(210, 211, 204, 0.5)`
- Text: `#23251d` `{colors.ink-subtle}`
- Padding: 12px 8px 4px 20px
- Radius: 0px 0px 6px 6px
- Font: 12px weight 400
- Use: Quiet action against page bg
- Focus: backgroundColor: `rgb(200, 202, 193)`

### Cards & Containers

**Standard Card**
- Background: `transparent`
- Padding: 16px 32px
- Radius: 0px
- Use: Content containers, listing items

### Navigation

**Main Nav**
- Background: `transparent`
- Padding: 0px
- Radius: none
- Font: 16px weight 400
- Use: Static block nav — N/A items

### Tabs

**Ghost Tab**
- Background: `transparent`
- Text: `#374151`
- Padding: 0px
- Radius: 0px
- Font: 15px weight 400
- Use: Navigation tabs, filter tabs

**Pill Tab**
- Background: `#2f80fa`
- Text: `#ffffff` `{colors.surface-2}`
- Padding: 10px 12px
- Radius: 6px 6px 0px 0px
- Font: 14px weight 600
- Use: Navigation tabs, filter tabs

### Code Blocks

**Inline Code / Pre**
- Background: `transparent`
- Text: `transparent`
- Padding: 0px
- Radius: 4px
- Font: 14px weight 500 — "Source Code Pro"
- Use: Code samples, CLI commands, syntax highlighting blocks

### Alerts

**Alert Banner**
- Background: `#ffffff` `{colors.surface-2}`
- Text: `#4d4f46`
- Padding: 16px
- Radius: 6px
- Border: 1px solid rgb(191, 193, 183)
- Font: 16px weight 400
- Use: System alert, banner notification, toast


## 4b. Component Behaviors (State Matrix)

### Interaction State Narrative

- **Button**:
  - **focus:** bg transparent → #c8cac1

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

```yaml
component-behaviors:
  button:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(35, 37, 29)"
    focus:
      bg: "rgb(200, 202, 193)"
      fg: "rgb(35, 37, 29)"
  link:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(77, 79, 70)"
  card:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(55, 65, 81)"
  navLink:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(77, 79, 70)"
  tab:
    default:
      bg: "rgba(0, 0, 0, 0)"
      fg: "rgb(101, 103, 94)"
```

**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
- **5 shape(s)** in this system: `Ghost`, `Primary Brand`, `Ghost`, `Light / Invert`, `Subtle`
- **DO NOT introduce new buttons variants** without justification

### Cards & Containers
- **1 shape(s)** in this system: `Standard Card`
- **DO NOT introduce new cards & containers variants** without justification

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

### Tabs
- **2 shape(s)** in this system: `Ghost Tab`, `Pill Tab`
- **DO NOT introduce new tabs variants** without justification

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

### Alerts
- **1 shape(s)** in this system: `Alert Banner`
- **DO NOT introduce new alerts variants** without justification

## 5. Layout Principles

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

### Grid
Flexbox column

### Max Width
1200px

### Spacing System
Compact spacing — information density prioritized

| Token | Value |
|-------|-------|
| xxs | 2px |
| xs | 4px |
| sm | 8px |
| md | 16px |
| base | 32px |
| lg | 24px |
| xl | 32px |
| 2xl | 48px |
| 3xl | 64px |

### Border Radius Scale
| Name | Value | Use |
|------|-------|-----|
| None | 0px | No rounding |
| Xs | 4px | Tiny corners (badges, micro elements) |
| Sm | 8px | Buttons, inputs, small elements |
| Md | 8px | Cards, containers |
| Lg | 8px | Large rounded elements, pill segments |
| Xl | 8px | Category strips, featured containers |
| Full | 9999px | Pills, avatars, circular elements |

### Shape Language

| Component | Border Radius |
|-----------|---------------|
| Buttons | `4px` |
| Cards & Containers | `0px` |
| Navigation | `none` |
| Tabs | `0px` |
| Code Blocks | `4px` |
| Alerts | `6px` |
| Page Body | `0px` |

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

**Full Radius Spectrum**: 0px, 2px, 4px, 5px, 6px, 8px, full/pill (from `allBorderRadii` scan)


## 5b. Spacing Rhythm Names

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

| Name | Value | Use case |
|------|-------|----------|
| **hero** | `64px` | 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** | `16px` | 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:** full-viewport hero (≥70% screen height)
- **Heading:** "" — 24px left-aligned
- **Subheading:** "The new way to build productsProduct development used to mean manually writing code, running analysis, diagnosing bugs, and rolling out changes using "
- **Media:** present, positioned right
- **CTAs:** 13 (primary: "Get started - free")
- **Clone instruction:** Reproduce the **split-left-text** layout. Use the heading font-size token at the documented size. Place media right of text.

### Card Grid Pattern

- **Card count:** 4 cards detected
- **Columns (desktop):** 4-up grid
- **Card dimensions:** 384×108px (aspect 3.55:1)
- **Gap:** 16px between cards
- **Content:** ✗ no image + icon
- **Clone instruction:** Build a 4-column grid (desktop) with cards at ~3.55:1 aspect ratio. Text/icon-only cards (no photography).

### Pricing Table Pattern

- **Tier count:** 2 pricing tiers
- **Layout:** vertical stacked
- **Columns (desktop):** 2-up
- **Feature list:** ✓ (median ~10 feature points per tier)
- **Clone instruction:** Build a 2-column vertical-stack pricing comparison.

### Footer Pattern

- **Columns:** 1
- **Links:** 0 total
- **Height:** 6px
- **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) 0px 0px 0px 0px`,<br>`rgba(0, 0, 0, 0) 0px 0px 0px 0px`,<br>`rgba(0, 0, 0, 0.25) 0px 25px 50px -12px` | Cards, elevated surfaces |
| Layered (Level 2) | <br>`rgba(0, 0, 0, 0) 0px 0px 0px 0px`,<br>`rgba(0, 0, 0, 0) 0px 0px 0px 0px`,<br>`rgba(0, 0, 0, 0.2) 0px 0px 6px 2px` | 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(0.4,0,0.2,1)` | Material Standard — Balanced |

### Duration Scale

| Value | Tier | Typical Use |
|-------|------|-------------|
| `150ms` | Fast | Hover states, micro-interactions |
| `300ms` | Normal | Panel open/close, navigation |

### Copy-Paste Transition Snippets

**All Props**
```css
transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
```

**Color / Background**
```css
transition: color 0.15s cubic-bezier(0.4, 0, 0.2, 1), background-color 0.15s cubic-bezier(0.4, 0, 0.2, 1), border-color 0.15s cub...;
```

**All Props**
```css
transition: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
```

### Keyframe Animation Catalog

| Animation Name | Type | Animated Props | Use Hint |
|----------------|------|----------------|----------|
| `slideRight` | Slide | transform | UI transition |
| `rcSliderTooltipZoomDownIn` | Fade + Move | opacity, transform, transform-origin | Focus / emphasis |
| `rcSliderTooltipZoomDownOut` | Fade + Move | transform, transform-origin, opacity | Focus / emphasis |
| `wobble` | Rotate / Spin | transform | UI transition |
| `breathe` | Scale | transform | UI transition |
| `develop` | Fade | filter, opacity | UI transition |
| `flash` | Scale | transform | UI transition |
| `float` | Slide | transform | UI transition |
| `gradient-rotate` | Custom | background-position-x, background-position-y | Loading indicator |
| `grow` | Scale | transform | UI transition |
| `grow-sm` | Scale | transform | UI transition |
| `hogfather-jump` | Custom | margin-top | UI transition |
| `hogfather-roll` | Scale | left, transform | UI transition |
| `jump-out` | Scale | transform | UI transition |
| `ping` | Fade + Move | opacity, transform | Attention / status |
| `pulse` | Fade | opacity | Attention / status |
| `shimmer` | Custom | background-position-x, background-position-y | Loading placeholder |
| `slideUpFadeIn` | Fade + Move | opacity, transform | Element entrance |
| `spin` | Rotate / Spin | transform | Loading indicator |
| `wiggle` | Rotate / Spin | transform | Playful feedback |

> *23 additional animations omitted (repetitive variants). See raw keyframes in `raw-css.json`.*

### Motion Fingerprint

- **Speed Character**: Deliberate & Calm (median duration: `300ms`)
- **Dominant Easing**: custom cubic-bezier curves
- **Animation Library**: 43 unique animations (43 total including variants)

> This design moves with deliberate & calm timing using custom cubic-bezier curves, creating a UI that feels calm and controlled.

## 8. Do's and Don'ts

### Do
- Use Light Gray (`#eeefe9`) as the page background — it's intentionally not pure white
- Use IBM Plex Sans Variable as the primary typeface — it defines the brand personality
- Use negative letter-spacing (-0.6px) at display sizes for compressed, editorial headlines
- 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 #cd8407 (`#cd8407`) as the primary accent — it's the brand's signature interactive color
- Use 6px border-radius on buttons — the standard corner rounding for interactive elements
- Apply 16px 32px padding inside cards — matches the design system's content breathing room
- Respect the 4px–32px spacing range — the design uses a wide scale for visual breathing room
- Make the hero full-viewport (≥70% screen height) — this design uses an immersive hero, not a tall navbar
- Build the hero as a split layout with media on the left — text and visual share equal weight
- Include exactly 13 CTAs in the hero (primary + secondary) — this design pattern is multi-action, not single-purpose
- Each card uses an icon (not photo) — the visual language is illustrative, not photographic
- Use a 4-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 substitute with generic sans-serif or serif — the custom font carries the brand
- Don't increase letter-spacing on headings — the type is designed to run tight at scale
- 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-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(238, 239, 233)` as the base canvas"
    why: "Every component is designed to composit against this exact tone"
    test: "document.body.style.backgroundColor === 'rgb(238, 239, 233)'"
  - id: brand-accent-001
    type: do
    rule: "Reserve `rgb(205, 132, 7)` for primary CTAs and brand-mark signals only"
    why: "Single chromatic assertion device — overuse dilutes meaning"
    test: "querySelectorAll('[style*=\"rgb(205, 132, 7)\"]').length <= 3 per fold"
```

## 9. Responsive Behavior

### Breakpoints
| Name | Width | Key Changes |
|------|-------|-------------|
| Mobile | 425px | Single column, compact spacing |
| Mobile Large | 482px | Expanded mobile layout |
| Mobile Large | 640px | Expanded mobile layout |
| Mobile Large | 767px | Expanded mobile layout |
| Tablet | 1024px | Multi-column grids begin |
| Desktop | 1280px | Full feature layout |

### Token Diff — Desktop vs Mobile

| Element | Property | Desktop | Mobile |
|---------|----------|---------|--------|
| nav | display | `block` | `flex` |
| button | width | `40px` | `80px` |
| card | padding | `16px 32px` | `16px` |
| card | width | `896px` | `388px` |
| sidebar | width | `267px` | `237px` |

### Collapsing Strategy
- Navigation: block → flex on mobile
- Cards: multi-column → stacked vertical on mobile
- Footer: multi-column → stacked single column on mobile

### Touch Targets
- Buttons: 2px 8px 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.
- **Card grid: 4-up → 1-up** — cards stack as viewport narrows, becoming a vertical list on mobile.

## 9b. Visual Tone & Photography

**Tone:** Mixed photography + illustration

A balanced mix of photographic content and vector graphics. Photos likely carry product/lifestyle context while SVG handles icons, logos, and decorative accents.

**Canonical Brand Image (OG):**
- https://posthog.com/images/og/default.png
  *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: 1:1 (square / portrait)
- Rendered size: 700×700px
- *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): 4 (44%)
- Portrait (<0.87): 1 (11%)
- Square (0.87–1.15): 4 (44%)

**Media Format Mix:**
- SVG: 1 (icons, illustrations, decorative geometry)

**Average rendered image size:** 315×255px
**Above-fold image count:** 4 / 9

**Decorative Patterns Detected:**
- 1 multi-stop linear gradient (mesh-like, 3+ color stops) — the brand leans on rich color transitions for visual depth
- 1 large decorative SVG shape (≥200×200px, non-icon) — likely blob/illustration accents
- **Glassmorphism** detected (`backdrop-filter: blur`) — layered transparent surfaces with blur, modern OS-like aesthetic

**Clone instruction for decorative work:** Glassmorphism is a brand signature — use `backdrop-filter: blur(20px)` on overlapping surfaces.

**Imagery Guidance for clones:**
- Mix photography and illustration intentionally: photos for product/context, vectors for icons + decorative accents.
- Respect the format split — replacing JPGs with illustrations (or vice versa) will shift the brand tone.

## 10. Agent Prompt Guide

### Quick Reference
- Background: Light Gray (`#eeefe9`)
- Primary text: Pure Black (`#000000`)
- Accent: #cd8407 (`#cd8407`)
- Border: Silver (`#bfc1b7`)
- Font: IBM Plex Sans Variable
- Body: 16px weight 400

### Example Component Prompts
- "Create a hero section on Light Gray background (#eeefe9). Headline at 24px IBM Plex Sans Variable weight 800, line-height 1.33, letter-spacing -0.6px, color #000000."
- "Create the primary CTA button: `#cd8407` background, `#23251d` text, 6px border-radius, 12px 24px padding, 700 weight, IBM Plex Sans Variable font."
- "Design a card on `transparent` background. Border: none. Radius: 0px. Shadow: none. Padding: 16px 32px."
- "Build navigation: static on `#eeefe9`. IBM Plex Sans Variable 16px weight 400 for links."

### Iteration Guide
1. **Canvas**: Set the light canvas to Light Gray (`#eeefe9`) — every component is composited against this exact base.
2. **Typography**: All type in IBM Plex Sans Variable, weight range 400–800. Never exceed 800 — heavier weights break the brand's tonal restraint.
3. **Accent**: #cd8407 (`#cd8407`) is the sole interactive color. On hover → Honey (`#b17816`). Use CSS transitions, not opacity/brightness filters.
4. **Motion**: All transitions use `cubic-bezier(0.4,0,0.2,1)`. Never use linear for UI transitions — preserve the brand's easing personality.
5. **Shape**: CTAs at `4px`, 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-background: #eeefe9;
  --ca-surface-1: #e5e7e0;
  --ca-surface-2: #ffffff;
  --ca-ink-subtle: #23251d;
  --ca-primary: #cd8407;
  --ca-on-primary: #111111;
  --ca-primary-hover: #b17816;
  --ca-hairline: #bfc1b7;
}

/* Typography */
:root {
  --ca-font-primary: "IBM Plex Sans Variable", system-ui, sans-serif;
  --ca-text-display: 24px;
  --ca-text-body: 16px;
  --ca-text-small: 15px;
  --ca-text-button: 13px;
}

/* Spacing & Radius */
:root {
  --ca-space-xxs: 2px;
  --ca-space-xs: 4px;
  --ca-space-sm: 8px;
  --ca-space-md: 16px;
  --ca-space-base: 32px;
  --ca-space-lg: 24px;
  --ca-space-xl: 32px;
  --ca-space-2xl: 48px;
  --ca-space-3xl: 64px;
  --ca-radius-none: 0px;
  --ca-radius-xs: 4px;
  --ca-radius-sm: 8px;
  --ca-radius-md: 8px;
  --ca-radius-lg: 8px;
  --ca-radius-xl: 8px;
  --ca-radius-full: 9999px;
}
```


## 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: unknown
    tag: div
    classes: ["@container", "absolute", "!select-auto", "flex"]
    height: 810px
    width: 960px
    layout: flex-column justify=normal
    children: 7
  - section: unknown
    tag: div
    classes: ["@container", "w-full", "h-full", "flex"]
    height: 771px
    width: 958px
    layout: flex-column justify=normal
    children: 2
  - section: main-content
    tag: main
    classes: ["@container/editor", "flex-1", "relative", "h-full"]
    height: 714px
    width: 958px
    layout: flex-column justify=normal
    children: 1
    bg: "rgb(253, 253, 248)"
  - section: unknown
    tag: div
    classes: ["@container"]
    height: 471px
    width: 832px
    layout: block
    children: 1
  - section: hero
    tag: div
    classes: ["data-[state=active]:animate-[hero-carousel-fade-in_300ms_ease-out]", "flex-1"]
    height: 415px
    width: 816px
    layout: block
    children: 1
  - section: unknown
    tag: div
    classes: ["OSTable", "md:@2xs/not-full-width:mx-0", "mb-2", "-mx-4"]
    height: 245px
    width: 864px
    layout: block
    children: 1
  - section: unknown
    tag: div
    classes: ["md:@2xs/not-full-width:px-0", "flex", "px-4", "@md/reader-content-container:px-6"]
    height: 245px
    width: 864px
    layout: flex-row justify=normal
    children: 1
    padding: "0px 16px"
  - section: section-1
    tag: section
    classes: ["pt-8", "@xl:pt-0", "px-5", "lg:px-0"]
    height: 512px
    width: 832px
    layout: block
    children: 2
```

**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:
    - "Understand what users are doing"
  sub-headings:
    - "Install with AI in a single prompt"
  ctas:
    - "Get started – free"
    - "Ask a question"
    - "Switch to website mode"
    - "home.mdx"
  navigation:
    - "home.mdx"
    - "Product OS"
    - "Pricing"
    - "customers.mdx"
    - "demo.mov"
    - "Docs"
    - "Talk to a human"
    - "Sign up ↗"
    - "Why PostHog?"
    - "Changelog"
```

**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: 2.22
    common-aspect: "~16:9 landscape"
    sample-alts:
      - "Ursula von der Leyen, President of the European Commission"
  product:
    count: 4
    avg-ratio: 1.01
    common-aspect: "~1:1 square"
```

**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">
  Action
</button>
```
_Source pattern detected: padding `2px 8px` · radius `4px` · weight `500`_

### Generic Card
```html
<div class="card">
  <!-- content -->
</div>
```
_Source pattern detected: padding `16px 32px` · radius `0px` · shadow `none`_

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


---
## Extraction Completeness: 89/100 (B)

| Category | Score | Max | Detail |
|----------|-------|-----|--------|
| Colors & Palette | 25 | 25 | 22 named colors |
| Typography | 18 | 20 | 7 roles defined |
| Components | 20 | 20 | 6 specs extracted |
| Motion & Interaction | 12 | 15 | Keyframes present |
| CSS Custom Properties | 5 | 10 | 99 vars |
| Responsive Breakpoints | 5 | 5 | 6 breakpoints |
| Variable Fonts | 5 | 5 | WGHT axes |

## 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.

| Category | What's missing | Fallback strategy |
|----------|----------------|-------------------|
| **Dark mode** | No dark-mode CSS variables or media queries detected | Light mode is canonical; do not generate dark-mode variants unless explicitly requested |
| **Form inputs** | No text input fields detected on this page | Use the documented border-radius + accent border on focus; 12-16px padding inside |

### Per-section confidence

| Section | Confidence | Reason |
|---------|------------|--------|
| §1 Visual Theme | High | Body bg extracted via getComputedStyle() |
| §2 Colors | High | 99 CSS vars (semantic naming requires ≥20 for high) |
| §3 Typography | High | 7 typography roles inferred |
| §4 Components | High | 6 component variants captured |
| §7 Motion | High | Keyframes + transitions |
| §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 | 9 images, hero present |

---
*Generated by Clone Architect — automated Playwright extraction + design analysis.*
*Source: https://posthog.com | 2026-05-30T20:39:41.718Z*
*All values verified via getComputedStyle() — no approximation, no hallucination.*