Skill

design-system

Extracts design system from websites, HTML files, or screenshots into DESIGN.md via Playwright automation, HTML inspection, and visual analysis for UI consistency.

HTML

Popularity

Parent stars

785

Parent forks

Invocation

How this skill is triggered — by the user, by Claude, or both

Slash command

/frontend:design-system

User invocable

Model invocable

Inline context

Default effort

Tool Access

This skill is limited to the following tools:

ReadWriteEditBashGlobGrep

Context Preview

The summary Claude sees in its skill listing — used to decide when to auto-load this skill

Analyse an existing website, HTML file, or screenshot and synthesise a semantic design system into a `DESIGN.md` file. The output is optimised for use with the `design-loop` skill and general page generation.

SKILL.md

230 lines · ~2.2k tokens

Stats

LanguagePython

Parent stars785

Parent forks72

MaintenanceExcellent

Last CommitApr 3, 2026

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Design System Extractor

Analyse an existing website, HTML file, or screenshot and synthesise a semantic design system into a DESIGN.md file. The output is optimised for use with the design-loop skill and general page generation.

When to Use

Starting a new project based on an existing site's visual language
Documenting a site's design system that was never formally written down
Preparing .design/DESIGN.md before running the design loop
Extracting brand guidelines from a client's existing website
Creating consistency documentation for a multi-page project
Extracting design tokens from a Google Stitch project

Workflow

Step 1: Identify the Source

Ask the user for one of:

Source	Method
Live URL	Browse via Playwright CLI or scraper, screenshot + extract HTML
Local HTML file	Read the file directly
Screenshot image	Analyse visually (limited — no exact hex extraction)
Existing project	Scan `site/public/` for HTML files to analyse
Stitch project	Use `@google/stitch-sdk` to fetch screen HTML + design theme

Step 2: Extract Raw Design Data

From a Live URL

Browse the site using Playwright CLI:

playwright-cli -s=design open {url}
playwright-cli -s=design screenshot --filename=.design/screenshots/source-desktop.png

Extract the full HTML — either via scraper MCP or by reading the page source

Resize and screenshot mobile (375px):

playwright-cli -s=design resize 375 812
playwright-cli -s=design screenshot --filename=.design/screenshots/source-mobile.png

Close the session: playwright-cli -s=design close

From a Local HTML File

Read the file directly and extract design tokens from the source.

From a Screenshot Only

Analyse the image visually. Note: colour extraction will be approximate without HTML source. Flag this limitation in the output.

From a Google Stitch Project

If @google/stitch-sdk is installed and STITCH_API_KEY is set:

import { stitch } from "@google/stitch-sdk";

// List projects to find the target
const projects = await stitch.projects();

// Get project details (includes designTheme)
const project = stitch.project(projectId);
const screens = await project.screens();

// Get HTML from the main screen
const screen = screens[0]; // or find by title
const htmlUrl = await screen.getHtml();
const imageUrl = await screen.getImage();

The Stitch designTheme object provides structured tokens directly:

{
  "colorMode": "DARK",
  "font": "INTER",
  "roundness": "ROUND_EIGHT",
  "customColor": "#40baf7",
  "saturation": 3
}

Map these to DESIGN.md sections:

colorMode → Theme (Light/Dark)
font → Typography font family
roundness → Component border-radius (ROUND_EIGHT = 8px, ROUND_SIXTEEN = 16px, etc.)
customColor → Primary brand colour
saturation → Colour vibrancy (1-5 scale)

Then also download and analyse the HTML for the full palette (Stitch's theme object only has the primary colour — the full palette is in the generated CSS).

Step 3: Analyse Design Tokens

Extract these from the HTML/CSS source:

Colours

Look in these locations (priority order):

CSS custom properties — :root { --primary: #hex; } or @theme blocks
Tailwind config — <script> block with tailwind.config or @theme in <style>
Inline styles — style="color: #hex" or style="background: #hex"
Tailwind classes — bg-blue-600, text-gray-900 (map to palette)
Computed from screenshot — last resort, approximate

For each colour found, determine its role:

Role	How to identify
Primary	Buttons, links, active states, brand elements
Background	`<body>` or `<html>` background
Surface	Cards, containers, elevated elements
Text Primary	`<h1>`, `<h2>`, main body text
Text Secondary	Captions, metadata, muted text
Border	Dividers, input borders, card borders
Accent	Badges, notifications, highlights

Typography

Extract:

Token	Where to find
Font families	Google Fonts `<link>`, `@import`, `font-family` in CSS
Heading weights	`font-bold`, `font-semibold`, or explicit `font-weight`
Body size	Base `font-size` on `<body>` or root
Line height	`leading-*` classes or `line-height` CSS
Letter spacing	`tracking-*` classes or `letter-spacing` CSS

Components

Identify patterns for:

Buttons — shape (rounded-full, rounded-lg), colours, padding, hover states
Cards — background, border, shadow, border-radius, padding
Navigation — sticky/static, background treatment, active indicator
Forms — input style, focus ring, label positioning
Hero sections — layout pattern, overlay treatment, CTA placement

Spacing & Layout

Max content width — look for max-w-* or explicit max-width
Section padding — typical vertical padding between sections
Grid system — column count, gap values
Whitespace philosophy — tight, balanced, generous, or dramatic

Step 4: Synthesise into Natural Language

Critical: The DESIGN.md should describe the design in semantic, natural language supported by exact values. This is not a CSS dump — it's a document a designer or AI can read to understand and reproduce the visual language.

Don't write	Write instead
`rounded-xl`	"Softly rounded corners (12px)"
`shadow-md`	"Subtle elevation with diffused shadow"
`#1E40AF`	"Deep Ocean Blue (#1E40AF) for primary actions"
`py-16`	"Generous section spacing with breathing room"

Step 5: Write DESIGN.md

Output the file to .design/DESIGN.md (or user-specified path).

Follow the structure from the design-loop skill's references/site-template.md — specifically the DESIGN.md Template section. The key sections are:

Visual Theme & Atmosphere — mood, vibe, philosophy
Colour Palette & Roles — table with role, name, hex, usage
Typography — font families, weights, sizes, line heights
Component Styles — buttons, cards, nav, forms
Layout Principles — max width, spacing, grid, whitespace
Design System Notes for Generation — the copy-paste block for baton prompts

Step 6: Verify Accuracy

If browser automation is available:

Generate a small test section (e.g. a card + button + heading) using the extracted design system
Screenshot it alongside the original
Compare visually — adjust any values that don't match

Step 7: Report to User

Present:

Summary of extracted tokens (colour count, fonts, component patterns)
The generated DESIGN.md location
Any tokens that were approximate (flagged with ⚠️)
Suggestions for manual review (colours from screenshots, ambiguous typography)

Handling Multiple Pages

If the site has multiple pages with different styles:

Analyse the homepage first — it usually has the most complete design language
Spot-check 2-3 inner pages for consistency
Note any page-specific overrides in the Component Styles section
If pages are wildly different, ask the user which page to use as the canonical source

Tips

Tailwind sites are easiest — the config block has everything
Google Fonts links are gold — they specify exact families and weights
CSS custom properties are reliable — they represent intentional design tokens
Inline Tailwind classes need interpretation — bg-slate-900 needs mapping to a role
Screenshots are last resort — accurate hex extraction from images is unreliable
Dark mode: Check for .dark class overrides or prefers-color-scheme media queries

Common Pitfalls

❌ Listing raw CSS values without semantic description
❌ Missing the dark mode palette (check for .dark class or media query)
❌ Ignoring component patterns (just listing colours isn't enough)
❌ Not including Section 6 (the copy-paste generation block)
❌ Approximate colours from screenshots without flagging the uncertainty

design-system

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Invocation

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Context Preview

SKILL.md

design-system

Popularity

Invocation

Tool Access

Context Preview

SKILL.md

Design System Extractor

When to Use

Workflow

Step 1: Identify the Source

Step 2: Extract Raw Design Data

From a Live URL

From a Local HTML File

From a Screenshot Only

From a Google Stitch Project

Step 3: Analyse Design Tokens

Colours

Typography

Components

Spacing & Layout

Step 4: Synthesise into Natural Language

Step 5: Write DESIGN.md

Step 6: Verify Accuracy

Step 7: Report to User

Handling Multiple Pages

Tips

Common Pitfalls

Similar Skills

Design System Extractor

When to Use

Workflow

Step 1: Identify the Source

Step 2: Extract Raw Design Data

From a Live URL

From a Local HTML File

From a Screenshot Only

From a Google Stitch Project

Step 3: Analyse Design Tokens

Colours

Typography

Components

Spacing & Layout

Step 4: Synthesise into Natural Language

Step 5: Write DESIGN.md

Step 6: Verify Accuracy

Step 7: Report to User

Handling Multiple Pages

Tips

Common Pitfalls

Similar Skills