---
name: PostHog
colors:
  primary: '#1e1f23'
  brand: '#F54E00'
  canvas: '#fdfdf8'
  foreground: '#4d4f46'
  heading: '#23251d'
  muted: '#65675e'
  surface: '#eeefe9'
  surface-sage: '#e5e7e0'
  surface-tan: '#d4c9b8'
  hairline: '#bfc1b7'
  border-light: '#b6b7af'
  placeholder: '#9ea096'
  accent-amber: '#F7A501'
  accent-gold: '#b17816'
  focus: '#3b82f6'
  on-primary: '#ffffff'
typography:
  display-hero:
    fontSize: 30px
    fontWeight: 800
    lineHeight: 1.2
    letterSpacing: '-0.75px'
    use: Hero headline — extra-bold, tight
  section:
    fontSize: 36px
    fontWeight: 700
    lineHeight: 1.5
    use: Section titles — large, generous line-height
  feature:
    fontSize: 24px
    fontWeight: 700
    lineHeight: 1.33
    use: Feature section titles
  subheading:
    fontSize: 20px
    fontWeight: 700
    lineHeight: 1.4
    letterSpacing: '-0.5px'
    use: Content sub-sections
  body-semi:
    fontSize: 18px
    fontWeight: 600
    lineHeight: 1.56
    use: Semi-bold body / callout text
  body:
    fontSize: 16px
    fontWeight: 400
    lineHeight: 1.5
    use: Standard reading text
  nav:
    fontSize: 15px
    fontWeight: 600
    lineHeight: 1.5
    use: Navigation and UI labels
  caption:
    fontSize: 14px
    fontWeight: 400
    lineHeight: 1.43
    use: Small text, captions
  micro:
    fontSize: 12px
    fontWeight: 500
    lineHeight: 1.33
    use: Tags, badges, smallest labels
  code:
    fontSize: 14px
    fontWeight: 500
    lineHeight: 1.43
    use: Code snippets and terminal
rounded:
  sm: 2px
  md: 4px
  lg: 6px
  full: 9999px
spacing:
  xs: 2
  sm: 4
  md: 8
  base: 12
  lg: 16
  xl: 24
  xxl: 32
  section: 48
components:
  button-primary:
    type: button
    backgroundColor: '#1e1f23'
    textColor: '#ffffff'
    rounded: 6px
    padding: 10px 12px
    typography: 15px / 600
    hover: 'opacity 0.7, text #F7A501'
    active: opacity 0.8, slight scale
    use: Main CTA — dark and confident
  button-sage:
    type: button
    backgroundColor: '#e5e7e0'
    textColor: '#4d4f46'
    rounded: 4px
    padding: 4px
    typography: 14px / 500
    hover: 'bg #f4f4f4, text #F54E00'
    use: Compact utility button
  button-tan:
    type: button
    backgroundColor: '#d4c9b8'
    textColor: '#000000'
    rounded: 0px
    padding: 10px 12px
    hover: 'text #F54E00'
    use: Featured/premium actions
  button-ghost:
    type: button
    backgroundColor: '#fdfdf8'
    textColor: '#4d4f46'
    border: 1px solid transparent
    rounded: 4px
    padding: 8px 12px
    hover: 'text #F54E00'
    use: Minimal-presence ghost button
  input-default:
    type: input
    backgroundColor: '#eeefe9'
    textColor: '#374151'
    border: '1px solid #b6b7af'
    rounded: 4px
    padding: 2px 0 2px 8px
    focus: '#3b82f6 ring at 50% opacity'
    use: Standard form input
  input-search:
    type: input
    backgroundColor: '#eeefe9'
    textColor: '#374151'
    border: '1px solid #b6b7af'
    rounded: 4px
    padding: 6px 8px
    use: Search/filter control
  card-bordered:
    type: card
    backgroundColor: '#fdfdf8'
    border: '1px solid #bfc1b7'
    rounded: 6px
    padding: 16px
    use: Clean minimal default card
  card-sage:
    type: card
    backgroundColor: '#eeefe9'
    border: '1px solid #bfc1b7'
    rounded: 4px
    padding: 16px
    use: Secondary content container
  card-shadow:
    type: card
    backgroundColor: '#fdfdf8'
    rounded: 6px
    padding: 16px
    shadow: 0px 25px 50px -12px rgba(0,0,0,0.25)
    hover: orange text flash
    use: Elevated content (modals, dropdowns)
  badge-default:
    type: badge
    backgroundColor: '#e5e7e0'
    textColor: '#4d4f46'
    rounded: 4px
    padding: 2px 8px
    typography: 12px / 500
    use: Default tag
  badge-featured:
    type: badge
    backgroundColor: '#d4c9b8'
    textColor: '#000000'
    rounded: 4px
    padding: 2px 8px
    typography: 12px / 600
    use: Warm tan featured tag
fonts:
  roles:
    sans: IBM Plex Sans Variable
    mono: Source Code Pro
---

# Design System Inspiration of PostHog

## Overview

### Visual Theme & Atmosphere

PostHog's website feels like a startup's internal wiki that escaped into the wild — warm, irreverent, and deliberately anti-corporate. The background isn't the expected crisp white or dark void of developer tools; it's a warm, sage-tinted cream (`#fdfdf8`) that gives every surface a handmade, paper-like quality. Colors lean into earthy olive greens and muted sage rather than the conventional blues and purples of the SaaS world. It's as if someone designed a developer analytics platform inside a cozy garden shed.

The personality is the star: hand-drawn hedgehog illustrations, quirky action figures, and playful imagery replace the stock photography and abstract gradients typical of B2B SaaS. IBM Plex Sans Variable serves as the typographic foundation — a font with genuine technical credibility (created by IBM, widely used in developer contexts) deployed here with bold weights (700, 800) on headings and generous line-heights on body text. The typography says "we're serious engineers" while everything around it says "but we don't take ourselves too seriously."

The interaction design carries the same spirit: hover states flash PostHog Orange (`#F54E00`) text — a hidden brand color that doesn't appear at rest but surprises on interaction. Dark near-black buttons (`#1e1f23`) use opacity reduction on hover rather than color shifts, and active states scale slightly. The border system uses sage-tinted grays (`#bfc1b7`) that harmonize with the olive text palette. Built on Tailwind CSS with Radix UI and shadcn/ui primitives, the technical foundation is modern and component-driven, but the visual output is stubbornly unique.

**Key Characteristics:**
- Warm sage/olive color palette instead of conventional blues — earthy and approachable
- IBM Plex Sans Variable font at bold weights (700/800) for headings with generous 1.50+ line-heights
- Hidden brand orange (`#F54E00`) that only appears on hover interactions — a delightful surprise
- Hand-drawn hedgehog illustrations and playful imagery — deliberately anti-corporate
- Sage-tinted borders (`#bfc1b7`) and backgrounds (`#eeefe9`) creating a unified warm-green system
- Dark near-black CTAs (`#1e1f23`) with opacity-based hover states
- Content-heavy editorial layout — the site reads like a magazine, not a typical landing page
- Tailwind CSS + Radix UI + shadcn/ui component architecture

### Primary tasks

- Track product analytics, feature flags, and session replay in one stack
- Self-host the platform to keep customer data on your own infrastructure
- Install the SDK so a new project starts capturing events
- Create a first insight from the template gallery
- Read the public handbook, roadmap, and board materials

### Brand Narrative

PostHog was founded **2020** by **James Hawkins (Co-CEO)** and **Tim Glaser (CTO/Co-CEO)** as an open-source alternative to Amplitude/Mixpanel (PostHog — About, Y Combinator — PostHog). The company **hatched in Y Combinator's W20 batch** and **launched on Hacker News with their MVP just 4 weeks after writing first code**. **Hawkins**: previously **VP Sales & Channels at Arachnys**; founded **c2o Media** before PostHog. **Glaser**: leads technical strategy, built PostHog on **ClickHouse + open-source frameworks**. Famous for **radical transparency** — **public handbook, public salaries, public roadmap, public board materials**. **From-pivot-hell-to-$1.4B-unicorn** YC library case study documents the journey (YC Library — Pivot Hell to $1.4B Unicorn). **Total funding ~$182M** from **Stripe, GV, Y Combinator** + angels including **Jason Warner (CTO GitHub)** and **Solomon Hykes (Founder Docker)** (PostHog — Reflecting on YC 2 years on, Tracxn — PostHog). **Used by 190,254+ teams** including **65% of YC batch companies**. The brand voice tracks this culture: scrappy, honest, occasionally meme-aware. The "Product OS" pivot in 2024-2025 expanded PostHog from analytics to **feature flags, session replay, surveys, A/B tests** as a single integrated product platform.

### Principles

1. **Open source is the default.** *UI implication:* self-hosting first-class option, never deprioritized.
2. **Radical transparency.** *UI implication:* handbook + roadmap publicly linked.
3. **Sage-tinted warm gray.** Borders `#bfc1b7`. *UI implication:* never neutral pure gray; warmth carries.
4. **Hedgehog mascot.** *UI implication:* mascot appears in product (404 pages, empty states) as personality moments.
5. **Wiki feel over corporate polish.** *UI implication:* documentation can be playful; chrome can have texture.

### Personas

*Personas are fictional archetypes informed by PostHog user segments (product engineers, indie devs, growth teams), not individual people.*

**Sarah Lin, 31, San Francisco.** Founding engineer at Series A. PostHog for analytics + feature flags + session replay in one stack.

**Henrik Sondergaard, 38, Copenhagen.** Indie SaaS founder. Self-hosts PostHog to keep customer data on his infra.

**Priya Krishnan, 27, Bengaluru.** Growth engineer at fintech. A/B tests + funnel analysis daily.

## Colors

### Primary
- **Olive Ink** (`#4d4f46`): Primary text color — a distinctive olive-gray that gives all text a warm, earthy tone
- **Deep Olive** (`#23251d`): Link text and high-emphasis headings — near-black with green undertone
- **PostHog Orange** (`#F54E00`): Hidden brand accent — appears only on hover states, a vibrant orange that surprises

### Secondary & Accent
- **Amber Gold** (`#F7A501`): Secondary hover accent on dark buttons — warm gold that pairs with the orange
- **Gold Border** (`#b17816`): Special button borders — an amber-gold for featured CTAs
- **Focus Blue** (`#3b82f6`): Focus ring color (Tailwind default) — the only blue in the system, reserved for accessibility

### Surface & Background
- **Warm Parchment** (`#fdfdf8`): Primary page background — warm near-white with yellow-green undertone
- **Sage Cream** (`#eeefe9`): Input backgrounds, secondary surfaces — light sage tint
- **Light Sage** (`#e5e7e0`): Button backgrounds, tertiary surfaces — muted sage-green
- **Warm Tan** (`#d4c9b8`): Featured button backgrounds — warm tan/khaki for emphasis
- **Hover White** (`#f4f4f4`): Universal hover background state

### Neutrals & Text
- **Olive Ink** (`#4d4f46`): Primary body and UI text
- **Muted Olive** (`#65675e`): Secondary text, button labels on light backgrounds
- **Sage Placeholder** (`#9ea096`): Placeholder text, disabled states — warm sage-green
- **Sage Border** (`#bfc1b7`): Primary border color — olive-tinted gray for all borders
- **Light Border** (`#b6b7af`): Secondary border, toolbar borders — slightly darker sage

### Semantic & Accent
- **PostHog Orange** (`#F54E00`): Hover text accent — signals interactivity and brand personality
- **Amber Gold** (`#F7A501`): Dark button hover accent — warmth signal
- **Focus Blue** (`#3b82f6` at 50% opacity): Keyboard focus rings — accessibility-only color
- **Dark Text** (`#111827`): High-contrast link text — near-black for important links

### Gradient System
- No gradients on the marketing site — PostHog's visual language is deliberately flat and warm
- Depth is achieved through layered surfaces and border containment, not color transitions

## Typography

### Font Family
- **Display & Body**: `IBM Plex Sans Variable` — variable font (100–700+ weight range). Fallbacks: `IBM Plex Sans, -apple-system, system-ui, Avenir Next, Avenir, Segoe UI, Helvetica Neue, Helvetica, Ubuntu, Roboto, Noto, Arial`
- **Monospace**: `ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, Liberation Mono, Courier New` — system monospace stack
- **Code Display**: `Source Code Pro` — with fallbacks: `Menlo, Consolas, Monaco`

### Hierarchy

| Role | Font | Size | Weight | Line Height | Letter Spacing | Notes |
|------|------|------|--------|-------------|----------------|-------|
| Display Hero | IBM Plex Sans Variable | 30px | 800 | 1.20 | -0.75px | Extra-bold, tight, maximum impact |
| Section Heading | IBM Plex Sans Variable | 36px | 700 | 1.50 | 0px | Large but generous line-height |
| Feature Heading | IBM Plex Sans Variable | 24px | 700 | 1.33 | 0px | Feature section titles |
| Card Heading | IBM Plex Sans Variable | 21.4px | 700 | 1.40 | -0.54px | Slightly unusual size (scaled) |
| Sub-heading | IBM Plex Sans Variable | 20px | 700 | 1.40 | -0.5px | Content sub-sections |
| Sub-heading Uppercase | IBM Plex Sans Variable | 20px | 700 | 1.40 | 0px | Uppercase transform for labels |
| Body Emphasis | IBM Plex Sans Variable | 19.3px | 600 | 1.56 | -0.48px | Semi-bold callout text |
| Label Uppercase | IBM Plex Sans Variable | 18px | 700 | 1.50 | 0px | Uppercase category labels |
| Body Semi | IBM Plex Sans Variable | 18px | 600 | 1.56 | 0px | Semi-bold body text |
| Body | IBM Plex Sans Variable | 16px | 400 | 1.50 | 0px | Standard reading text |
| Body Medium | IBM Plex Sans Variable | 16px | 500 | 1.50 | 0px | Medium-weight body |
| Body Relaxed | IBM Plex Sans Variable | 15px | 400 | 1.71 | 0px | Relaxed line-height for long reads |
| Nav / UI | IBM Plex Sans Variable | 15px | 600 | 1.50 | 0px | Navigation and UI labels |
| Caption | IBM Plex Sans Variable | 14px | 400–700 | 1.43 | 0px | Small text, various weights |
| Small Label | IBM Plex Sans Variable | 13px | 500–700 | 1.00–1.50 | 0px | Tags, badges, micro labels |
| Micro | IBM Plex Sans Variable | 12px | 400–700 | 1.33 | 0px | Smallest text, some uppercase |
| Code | Source Code Pro | 14px | 500 | 1.43 | 0px | Code snippets and terminal |

### Principles
- **Bold heading dominance**: Headings use 700–800 weight — PostHog's typography is confident and assertive, not whispery
- **Generous body line-heights**: Body text at 1.50–1.71 line-height creates extremely comfortable reading — the site is content-heavy and optimized for long sessions
- **Fractional sizes**: Several sizes (21.4px, 19.3px, 13.7px) suggest a fluid/scaled type system rather than fixed stops — likely computed from Tailwind's rem scale at non-standard base
- **Uppercase as category signal**: Bold uppercase labels (18px–20px weight 700) are used for product category headings — a magazine-editorial convention
- **Selective negative tracking**: Letter-spacing tightens on display text (-0.75px at 30px) but relaxes to 0px on body — headlines compress, body breathes

## Layout

### Spacing System
- **Base unit**: 8px
- **Scale**: 2px, 4px, 6px, 8px, 10px, 12px, 16px, 18px, 24px, 32px, 34px
- **Section padding**: 32px–48px vertical between sections (compact for a content-heavy site)
- **Card padding**: 4px–12px internal (notably compact)
- **Component gaps**: 4px–8px between related elements

### Grid & Container
- **Max width**: 1536px (largest breakpoint), with content containers likely 1200px–1280px
- **Column patterns**: Varied — single column for text content, 2-3 column grids for feature cards, asymmetric layouts for product demos
- **Breakpoints**: 13 defined — 1px, 425px, 482px, 640px, 768px, 767px, 800px, 900px, 1024px, 1076px, 1160px, 1280px, 1536px

### Whitespace Philosophy
- **Content-dense by design**: PostHog's site is information-rich — whitespace is measured, not lavish
- **Editorial pacing**: Content sections flow like a magazine with varied layouts keeping the eye moving
- **Illustrations as breathing room**: Hand-drawn hedgehog art breaks up dense content sections naturally

### Border Radius Scale
- **2px**: Small inline elements, tags (`span`)
- **4px**: Primary UI components — buttons, inputs, dropdowns, menu items (`button`, `div`, `combobox`)
- **6px**: Secondary containers — larger buttons, list items, card variants (`button`, `div`, `li`)
- **9999px**: Pill shape — badges, status indicators, rounded tags (`span`, `div`)

### Responsive Behavior

#### Breakpoints
| Name | Width | Key Changes |
|------|-------|-------------|
| Mobile Small | <425px | Single column, compact padding, stacked cards |
| Mobile | 425px–640px | Slight layout adjustments, larger touch targets |
| Tablet | 640px–768px | 2-column grids begin, nav partially visible |
| Tablet Large | 768px–1024px | Multi-column layouts, expanded navigation |
| Desktop | 1024px–1280px | Full layout, 3-column feature grids, expanded mega-menu |
| Large Desktop | 1280px–1536px | Max-width container, generous margins |
| Extra Large | >1536px | Centered container at max-width |

#### Touch Targets
- Buttons: 4px–6px radius with `4px–12px` padding — compact but usable
- Nav links: 15px text at weight 600 with adequate padding
- Mobile: Hamburger menu with simplified navigation
- Inputs: Generous vertical padding for thumb-friendly forms

#### Collapsing Strategy
- **Navigation**: Full mega-menu with dropdowns → hamburger menu on mobile
- **Feature grids**: 3-column → 2-column → single column stacked
- **Typography**: Display sizes reduce across breakpoints (30px → smaller)
- **Illustrations**: Scale within containers, some may hide on mobile for space
- **Section spacing**: Reduces proportionally while maintaining readability

#### Image Behavior
- Illustrations scale responsively within containers
- Product screenshots maintain aspect ratios
- Trust logos reflow into multi-row grids on mobile
- AI chat widget may reposition or simplify on small screens

## Elevation & Depth

| Level | Treatment | Use |
|-------|-----------|-----|
| Level 0 (Flat) | No shadow, warm parchment background | Page canvas, most surfaces |
| Level 1 (Border) | `1px solid #bfc1b7` (Sage Border) | Card containment, input borders, section dividers |
| Level 2 (Compound Border) | Multiple 1px borders on different sides | Input groupings, toolbar elements |
| Level 3 (Deep Shadow) | `0px 25px 50px -12px rgba(0, 0, 0, 0.25)` | Modals, floating elements, mega-menu dropdowns |

### Shadow Philosophy
PostHog's elevation system is remarkably minimal — only one shadow definition exists in the entire system. Depth is communicated through:
- **Border containment**: Sage-tinted borders (`#bfc1b7`) at 1px create gentle warm separation
- **Surface color shifts**: Moving from `#fdfdf8` to `#eeefe9` to `#e5e7e0` creates layered depth without shadows
- **The single shadow**: The one defined shadow (`0 25px 50px -12px`) is reserved for floating elements — modals, dropdowns, popovers. It's a deep, dramatic shadow that creates clear separation when needed

### Decorative Depth
- **Illustration layering**: Hand-drawn hedgehog art creates visual depth naturally
- **No gradients or glow**: The flat, warm surface system relies entirely on border and surface-color differentiation
- **No glassmorphism**: Fully opaque surfaces throughout

### Values kept in prose

Measured values the DESIGN.md token grammar cannot carry, kept verbatim:

- `shadow.deep`: `0px 25px 50px -12px rgba(0,0,0,0.25)`

## Motion & Easing

**No motion duration or easing token is promoted.** The capture bundle for this
reference records no transition or animation property, and no official source consulted
publishes a motion scale. The behaviour described below was observed; treat any exact
duration or curve as a local extension until a component-level official source verifies it.

Standard cubic-bezier. Hedgehog mascot moments are personality, not chrome. `prefers-reduced-motion: reduce` makes mascot static.

---

## Components

### Buttons

**Dark Primary**
- Background: `#1e1f23`
- Text: `#ffffff`
- Radius: 6px
- Padding: 10px 12px
- Font: 15px / 600 / IBM Plex Sans
- Hover: opacity 0.7, text shifts to Amber Gold `#F7A501`
- Active: opacity 0.8, slight scale transform
- Use: Main CTA — dark and confident

**Sage Light**
- Background: `#e5e7e0`
- Text: `#4d4f46` (Olive Ink)
- Radius: 4px
- Padding: 4px
- Font: 14px / 500 / IBM Plex Sans
- Hover: bg `#f4f4f4`, text shifts to PostHog Orange `#F54E00`
- Use: Compact utility button

**Warm Tan Featured**
- Background: `#d4c9b8`
- Text: `#000000`
- Radius: 0px
- Padding: 10px 12px
- Hover: text flash to PostHog Orange `#F54E00`
- Use: Featured/premium actions

**Near-white Ghost**
- Background: `#fdfdf8`
- Text: `#4d4f46` (Olive Ink)
- Border: 1px solid transparent
- Radius: 4px
- Padding: 8px 12px
- Hover: text flash to PostHog Orange `#F54E00`
- Use: Minimal-presence ghost button

### Inputs

**Default**
- Background: `#eeefe9`
- Text: `#374151`
- Border: 1px solid `#b6b7af`
- Radius: 4px
- Padding: 2px 0px 2px 8px
- Placeholder: `#9ea096` (Sage Placeholder)
- Focus: `#3b82f6` ring at 50% opacity (Tailwind blue focus ring)
- Use: Standard form input — multiple border patterns; some inputs use compound borders (top/left/bottom-only)

**Search / Filter**
- Background: `#eeefe9`
- Text: `#374151`
- Border: 1px solid `#b6b7af`
- Radius: 4px
- Padding: 6px 8px
- Placeholder: `#9ea096`
- Use: Search/filter control

### Cards

**Bordered Card**
- Background: `#fdfdf8` (Warm Parchment) or `#ffffff`
- Border: 1px solid `#bfc1b7`
- Radius: 6px
- Padding: 16px
- Use: Clean and minimal default card

**Sage Surface Card**
- Background: `#eeefe9`
- Border: 1px solid `#bfc1b7`
- Radius: 4px
- Padding: 16px
- Use: Secondary content container

**Shadow Card**
- Background: `#fdfdf8`
- Radius: 6px
- Padding: 16px
- Shadow: `0px 25px 50px -12px rgba(0, 0, 0, 0.25)`
- Hover: Orange text flash on interactive cards
- Use: Elevated content (modals, dropdowns)

### Badges

**Default**
- Background: `#e5e7e0`
- Text: `#4d4f46`
- Radius: 4px
- Padding: 2px 8px
- Font: 12px / 500 / IBM Plex Sans
- Use: Inferred from §1-§2 baseline (no explicit DS variant in source).

**Featured**
- Background: `#d4c9b8`
- Text: `#000000`
- Radius: 4px
- Padding: 2px 8px
- Font: 12px / 600 / IBM Plex Sans
- Use: Inferred from §1-§2 baseline (no explicit DS variant in source) — warm tan featured tag.

### Navigation
- **Top nav**: Warm background, IBM Plex Sans at 15px weight 600
- **Dropdown menus**: Rich mega-menu structure with product categories
- **Link color**: Deep Olive (`#23251d`) for nav links, underline on hover
- **CTA**: Dark Primary button (#1e1f23) in the nav — "Get started - free"
- **Mobile**: Collapses to hamburger with simplified menu

### Image Treatment
- **Hand-drawn illustrations**: Hedgehog mascot and quirky illustrations — the signature visual element
- **Product screenshots**: UI screenshots embedded in device frames or clean containers
- **Action figures**: Playful product photography of hedgehog figurines — anti-corporate
- **Trust logos**: Enterprise logos (Airbus, GOV.UK) displayed in a muted trust bar
- **Aspect ratios**: Mixed — illustrations are irregular, screenshots are 16:9 or widescreen

### AI Chat Widget
- Floating PostHog AI assistant with speech bubble — an interactive product demo embedded in the marketing site

### States

| State | Treatment |
|---|---|
| **Empty (no events)** | "Install PostHog SDK to start" code snippet |
| **Empty (no insights)** | "Create your first insight" with template gallery |
| **Loading (query)** | Per-step execution visible |
| **Loading (replay loading)** | Session video loader with frame previews |
| **Error (SDK not detected)** | Specific instructions + verify-installation button |
| **Error (rate limit)** | Plain explanation + upgrade link |
| **Success (event captured)** | Implicit; events appear in feed |
| **Success (insight saved)** | Soft confirmation, no celebration |
| **Skeleton (insight grid)** | Sage-tinted placeholders |
| **Disabled (free plan)** | Upgrade link — never block existing OSS features |
| **Loading (long replay)** | Persistent progress |

## Do's and Don'ts

### Do
- Use the olive/sage color family (#4d4f46, #23251d, #bfc1b7) for text and borders — the warm green undertone is essential to the brand
- Flash PostHog Orange (#F54E00) on hover states — it's the hidden brand signature
- Use IBM Plex Sans at bold weights (700/800) for headings — the font carries technical credibility
- Keep body text at generous line-heights (1.50–1.71) — the content-heavy site demands readability
- Maintain the warm parchment background (#fdfdf8) — not pure white, never cold
- Use 4px border-radius for most UI elements — keep corners subtle and functional
- Include playful, hand-drawn illustration elements — the personality is the differentiator
- Apply opacity-based hover states (0.7 opacity) on dark buttons rather than color shifts

### Don't
- Use blue, purple, or typical tech-SaaS colors — PostHog's palette is deliberately olive/sage
- Add heavy shadows — the system uses one shadow for floating elements only; everything else uses borders
- Make the design look "polished" or "premium" in a conventional sense — PostHog's charm is its irreverent, scrappy energy
- Use tight line-heights on body text — the generous 1.50+ spacing is essential for the content-heavy layout
- Apply large border-radius (12px+) on cards — PostHog uses 4px–6px, keeping things tight and functional
- Remove the orange hover flash — it's a core interaction pattern, not decoration
- Replace illustrations with stock photography — the hand-drawn hedgehog art is the brand
- Use pure white (#ffffff) as page background — the warm sage-cream (#fdfdf8) tint is foundational

## Voice & Tone

PostHog's voice is **scrappy-startup-wiki and engineer-honest.** "We make dev tools for product engineers" — terse, capability-driven, slightly irreverent. Sage-tinted gray (`#bfc1b7`) borders + warm canvas signal "small but serious team that ships." Famous for company handbook being entirely public (posthog.com/handbook).

| Context | Tone |
|---|---|
| CTA | Verb. "Get started", "Sign up", "Talk to sales" |
| Marketing | Capability-list with personality. "Product OS" framing |
| Documentation | Wiki-style, deeply linked, occasional jokes |
| Handbook | Radically transparent — even sensitive topics |

**Voice samples**
- Marketing tagline: *"We make dev tools for product engineers"* <!-- verified: posthog.com homepage 2026-05 -->

**Forbidden phrases.** "Revolutionary product analytics". Aggressive Amplitude-comparison framing.

## Agent Prompt Guide

### Quick Color Reference
- Primary Text: Olive Ink (`#4d4f46`)
- Dark Text: Deep Olive (`#23251d`)
- Hover Accent: PostHog Orange (`#F54E00`)
- Dark CTA: Near-Black (`#1e1f23`)
- Button Surface: Light Sage (`#e5e7e0`)
- Page Background: Warm Parchment (`#fdfdf8`)
- Border: Sage Border (`#bfc1b7`)
- Placeholder: Sage Placeholder (`#9ea096`)

### Example Component Prompts
- "Create a hero section on warm parchment background (#fdfdf8) with 30px IBM Plex Sans heading at weight 800, line-height 1.20, letter-spacing -0.75px, olive ink text (#4d4f46), and a dark CTA button (#1e1f23, 6px radius, white text, opacity 0.7 on hover)"
- "Design a feature card with #fdfdf8 background, 1px #bfc1b7 border, 4px radius, IBM Plex Sans heading at 20px weight 700, and 16px body text at weight 400 with 1.50 line-height in olive ink (#4d4f46)"
- "Build a navigation bar with warm background, IBM Plex Sans links at 15px weight 600 in deep olive (#23251d), underline on hover, and a dark CTA button (#1e1f23) at the right"
- "Create a button group: primary dark (#1e1f23, white text, 6px radius), secondary sage (#e5e7e0, #4d4f46 text, 4px radius), and ghost/text button — all flash #F54E00 orange text on hover"
- "Design an input field with #eeefe9 background, 1px #b6b7af border, 4px radius, #9ea096 placeholder text, focus ring in #3b82f6 at 50% opacity"

### Iteration Guide
When refining existing screens generated with this design system:
1. Verify the background is warm parchment (#fdfdf8) not pure white — the sage-cream warmth is essential
2. Check that all text uses the olive family (#4d4f46, #23251d) not pure black or neutral gray
3. Ensure hover states flash PostHog Orange (#F54E00) — if hovering feels bland, you're missing this
4. Confirm borders use sage-tinted gray (#bfc1b7) not neutral gray — warmth runs through every element
5. The overall tone should feel like a fun, scrappy startup wiki — never corporate-polished or sterile