Extract Design#

Output Location#

CRITICAL: All extracted style files MUST be saved to the skill's own assets/theme/ directory — never to the user's project directory, never to a relative path from the current working directory.

Before writing any output file, resolve the skill directory by running:

text

Glob pattern: **/skills/extract-design/SKILL.md

The directory containing that SKILL.md file is SKILL_DIR. All output goes under SKILL_DIR/assets/theme/.

Output files use the source domain or project name as a prefix:

text

SKILL_DIR/assets/theme/
├── {name}-style-manifest.json    # Structured style manifest
└── {name}-style-specimen.html    # Universal style specimen HTML

Examples (where SKILL_DIR is whatever path the Glob resolved):

• {SKILL_DIR}/assets/theme/ampcode-style-manifest.json
• {SKILL_DIR}/assets/theme/ampcode-style-specimen.html
• {SKILL_DIR}/assets/theme/vercel-style-manifest.json
• {SKILL_DIR}/assets/theme/vercel-style-specimen.html

Create the assets/theme/ directory if it does not exist before writing.

---

Reference Files#

The references/ directory inside this skill contains two files you MUST use during every extraction. Both paths are relative to SKILL_DIR (resolved via Glob above):

• {SKILL_DIR}/references/extraction-checklist.md — comprehensive checklist for all extraction dimensions. Work through every section; note why if a dimension is not applicable.
• {SKILL_DIR}/references/style-specimen.html — structural template for Output C. Your generated specimen must follow the same structure.

WARNING: The template contains /* REPLACE */ placeholders for every CSS token value. You MUST replace ALL of them with values measured from the target site. Do NOT keep any placeholder value in the final output. A /* REPLACE */ in the output file means the extraction is incomplete.

---

When to use#

Use this skill when the user wants to:

• 提取某个网页的视觉风格
• 让 AI 学习一个网站的设计语言并生成同风格页面
• 从网页中抽取字体、字号、字色、背景样式、图片背景、条纹/网格/纹理、动画、卡片样式、代码块样式
• 将网页风格沉淀为一个可复用的 HTML 参考文件
• 构建设计样张页 / style specimen / design reference file
• 将一个具体网页抽象成更通用的设计系统表达
• 抽取整页“氛围感 / atmosphere / art direction”，而不仅是组件样式

Do not use this skill if the user wants:

• 仅截图网页
• 仅复制页面 DOM 或下载页面资源
• 仅修复某个单独 CSS 问题
• 仅做像素级 1:1 复刻
• 仅导出 raw CSS dump

This skill is for style system extraction, not page cloning.

---

Core principle#

Your task is not to reproduce the page structure.

Your task is to extract the page's visual system and represent it as:

1. Primitive tokens
2. Semantic tokens
3. Background / atmosphere system
4. Decorative motif system
5. Component archetypes
6. Interaction rules
7. A universal style specimen HTML

The final result must be a general-purpose reference file that another AI can read and use to generate new pages in the same style.

Think in terms of:

• design tokens
• semantic roles
• theme layers
• background atmosphere
• decorative motifs
• component patterns
• state behavior
• motion language
• responsive rules
• art direction

Do not think in terms of:

• copying all classes
• mirroring page DOM
• dumping raw CSS blindly
• preserving irrelevant content text
• flattening atmospheric styling into a single background color

The goal is:

Preserve not only the component language, but also the page atmosphere, decorative motifs, and art direction. A faithful extraction must capture both system structure and visual mood.

---

Output contract#

When using this skill, produce three outputs:

Output A — Extraction summary#

A concise explanation of the extracted style system:

• overall design character
• typography system
• color system
• spacing/layout rhythm
• surface/elevation language
• background / atmosphere language
• decorative motifs
• motion language
• component family
• theme/responsive behavior
• extraction confidence
• limitations

Output B — Structured style manifest#

A required machine-readable JSON file saved to {SKILL_DIR}/assets/theme/{name}-style-manifest.json, describing:

• meta
• primitives
• semantic tokens
• background system
• motifs
• themes
• motion tokens
• component archetypes
• responsive rules
• accessibility notes
• limitations

Output C — Universal style specimen HTML#

A single HTML file containing:

• CSS tokens
• theme layers
• background/atmosphere layers
• motif samples
• component styles
• specimen sections
• a design manifest in <script type="application/json">
• optional minimal demo scripts for theme switching / state preview

This HTML file should be general and reusable.

---

Required extraction dimensions#

You must extract the following categories.

1. Meta context#

Capture:

• source URL if available
• page title
• capture time/context
• viewport size
• whether dark mode exists
• whether reduced motion behavior exists
• whether the page uses heavy canvas/WebGL/video-only visuals
• whether shadow DOM/custom elements are present
• whether the extraction is from live render or static code

2. Typography#

Extract:

• primary font family
• fallback stack
• mono/code font family
• font weights
• size scale
• line heights
• letter spacing
• paragraph rhythm
• link styles
• prose/body styles
• heading hierarchy
• button/label/input text styles

Do not only report raw values. Abstract them into roles such as:

• --font-family-sans
• --font-family-mono
• --font-size-body
• --font-size-heading-lg
• --line-height-body
• --font-weight-semibold

3. Color system#

Extract:

• page background
• surface/background layers
• card backgrounds
• overlay/scrim
• primary text
• secondary text
• inverse text
• muted text
• borders/dividers
• brand/accent colors
• interactive colors
• success/warning/error/info
• code block background and syntax colors
• gradients
• translucent layers
• blur/frosted surface styles

Abstract colors into semantic roles, not just raw hex values.

Examples:

• --color-bg-page
• --color-surface-card
• --color-text-primary
• --color-text-secondary
• --color-border-default
• --color-brand-primary
• --color-code-bg

4. Spacing and layout#

Extract:

• container widths
• grid behavior
• gutter
• section spacing
• component padding
• gap rhythm
• common stack spacing
• alignment preferences
• desktop/tablet/mobile changes

Abstract into spacing and layout tokens.

5. Surface / shape / elevation#

Extract:

• border radius scale
• border treatments
• shadow scale
• backdrop blur
• surface layering
• z-index/elevation feel
• outline/focus ring style

Examples:

• --radius-sm
• --radius-card
• --shadow-sm
• --shadow-elevated
• --focus-ring

6. Motion / Animation#

Extract motion and animation tokens:

Transitions (via computed styles):

• transition durations
• easing curves
• delays
• common hover motion
• transform language
• opacity motion

@keyframes animations (require direct stylesheet parsing):

• Each @keyframes rule must be captured separately — extract-styles.py does NOT capture these
• For each keyframe, record: name, semantic description, from/to/keyframe percentages, usage context

How to extract @keyframes — run {SKILL_DIR}/scripts/extract-keyframes.py or this browser console snippet:

javascript

const keyframes = [];
for (const sheet of document.styleSheets) {
  try {
    for (const rule of sheet.cssRules) {
      if (rule.type === CSSRule.KEYFRAMES_RULE) {
        keyframes.push({ name: rule.name, cssText: rule.cssText });
      }
    }
  } catch(e) { /* CORS restriction, skip */ }
}
console.log(JSON.stringify(keyframes, null, 2));

Abstract into motion tokens:

• --motion-duration-fast, --motion-duration-normal
• --motion-ease-standard, --motion-ease-emphasized

Animation archetypes to look for:

• Modal/drawer: scaleIn, scaleOut, enterFromRight/Left
• Accordion: accordion-down/up
• Pattern: slidePattern (background pattern drift)
• Loading: spin, pulse, shimmer, progress-slide
• Reveal: fadeIn, slideUp, enter
• Hover: subtle scale, lift, glow

7. Component archetypes#

Extract reusable component families rather than page-specific instances.

At minimum inspect:

• page/container sections
• nav/header/footer
• buttons
• links
• cards
• badges/tags/chips
• inputs/textareas/selects
• switches/checkboxes/radios
• tabs/accordions
• tables
• alerts/callouts
• modals/drawers/popovers/tooltips
• lists/media rows
• empty states
• stat cards
• code blocks
• inline code
• toasts/skeletons if present

For each component archetype record:

• structure/slots
• visual DNA
• spacing
• radius
• border/shadow
• default state
• hover
• focus-visible
• active
• selected
• disabled
• loading
• theme variants
• compact/comfortable variants if visible

8. Code block system#

This is mandatory if code blocks exist or may matter later.

Extract:

• code font
• code size
• line height
• block background
• border/radius
• padding
• title bar / filename strip
• line-number style
• inline code style
• syntax color family
• copy button / toolbar style
• highlighted line style

9. Responsive and theme rules#

Capture:

• breakpoints
• type scaling across breakpoints
• spacing changes across breakpoints
• layout collapse/stack behavior
• theme variants
• dark mode
• reduced motion handling
• print behavior if visible or inferable

10. Atmosphere / Background System#

Extract the page-level and section-level visual atmosphere, not only flat background colors.

You must inspect and abstract:

• page background color
• section background color
• hero background treatments
• gradients (linear / radial / conic)
• repeating patterns (stripes / grid / dots / lines / checker / mesh)
• image-based backgrounds
• SVG decorative backgrounds
• noise / grain / texture overlays
• glow / blur / vignette / spotlight effects
• background blend / mask / filter usage
• pseudo-element decorative layers ( ::before, ::after)
• absolutely positioned decorative elements
• floating blobs / glow shapes / ambient lights
• background repeat / size / position / attachment
• section separators / dividers that contribute to overall mood
• whether the site atmosphere is flat / textured / editorial / futuristic / industrial / terminal-like / soft / playful

Do not flatten atmospheric styling into a single background-color. Always model it as a distinct system.

Examples of useful semantic outputs:

• --bg-page-base
• --bg-page-overlay
• --bg-page-pattern
• --bg-hero-gradient
• --bg-section-muted
• --pattern-stripe-color
• --pattern-grid-color
• --texture-noise-opacity
• --ambient-glow-primary
• --ambient-glow-blur
• --decorative-line-opacity

11. Decorative Motif System#

Extract repeated visual motifs that may appear in only a few places but clearly shape the site’s identity.

You must inspect and abstract:

• diagonal stripes
• grids
• dotted fields
• editorial rules/lines
• terminal scan lines
• waveform / chart-like lines
• geometric accents
• glow shapes
• border corner treatments
• repeated iconography
• signature hover textures
• signature pattern movement
• recurring mask or clipping styles
• recurring pseudo-element decorations

A motif may originate in one component but still represent page-level visual DNA. Elevate it when appropriate.

Useful outputs include:

• motifs.diagonal-stripe
• motifs.gridline
• motifs.editorial-rule
• motifs.noise-overlay
• motifs.ambient-glow
• motifs.scanline

---

Extraction method#

Rule 1: Prefer rendered reality over source intent#

Use the final rendered/computed result as the ground truth.

Prioritize:

• actual visible DOM
• computed styles
• pseudo elements
• measured layout
• live states
• effective animations

Do not rely solely on authored CSS.

Mandatory computed style checks — before recording any token value, use browser tools to read the actual computed value. Do not infer from class names, design system conventions, or framework patterns. Specifically:

• Read document.documentElement.getAttribute('data-theme') to confirm the actual default theme on page load. Never assume dark-first or light-first from visual appearance alone.
• Read CSS custom properties via getComputedStyle(document.documentElement).getPropertyValue('--var-name') to get exact values.
• Read computed colors via getComputedStyle(el).backgroundColor, .color, .borderColor etc. — not from class names.
• Read computed transitions via getComputedStyle(el).transition to get the actual easing curve, not a generic approximation.
• Read background-image on all elements to detect patterns, gradients, and motifs.

If a value cannot be read via computed style (e.g. cross-origin stylesheet blocked, canvas-only visuals), you must label it as "inferred" in the manifest's limitations field. Do not silently use an approximated value as if it were measured.

Rule 2: Cluster before naming#

Do not emit a token for every distinct observed value.

Instead:

1. collect raw values
2. group near-equivalent visual values
3. infer the system
4. assign semantic names

Example:

Bad:

• --blue-1
• --blue-2
• --blue-3
• --text-gray-7

Better:

• --color-brand-primary
• --color-link-default
• --color-link-hover
• --color-text-secondary

Rule 3: Extract semantic roles, not only raw values#

A useful reference file must explain what a value does, not only what the value is.

Always try to map raw observations into roles.

Rule 4: Extract states actively#

Do not assume the static DOM shows all relevant UI states.

For every component archetype in the manifest, you must record all of the following states:

• default
• hover
• focus-visible
• active
• selected
• disabled
• loading

If a state cannot be reliably observed, you must explicitly record it as "inferred" or "unavailable" — do not omit it silently. A missing state entry is not the same as an unavailable state.

Rule 5: Build archetypes, not clones#

If you see 11 cards, do not export 11 card classes unless they are meaningfully distinct.

Instead compress them into a small set of archetypes, for example:

• card/plain
• card/bordered
• card/elevated
• card/interactive
• card/stat

Rule 6: Separate content from style#

The specimen file should use neutral placeholder content.

Do not preserve source page copy unless the user explicitly asks.

Rule 7: Report uncertainty honestly#

If some styles are not reliably extractable, say so.

Never emit an empty object or empty array for a field you could not extract. Instead:

• If the value is genuinely absent from the design (e.g. no shadows used), set the field to null and add a note to limitations.
• If the value exists but could not be measured, set it to "inferred: <reason>" or add it to limitations.

Bad:

json

"shadow": {}
"surfaces": {}

Good:

json

"shadow": null,
"limitations": ["Shadow styles not observed — site appears to use no box-shadow"]

Typical limitations include:

• cross-origin stylesheet access issues
• canvas/WebGL-only visuals
• video-only backgrounds
• runtime-only transitions not visible in current state
• visited-link privacy behavior
• hard-to-observe interaction states

Rule 8: Extract atmosphere separately from components#

A page may feel distinctive because of background treatment, not because of buttons or cards.

Always inspect atmosphere at 4 levels: page-level ( html/ body/main wrappers), section-level (hero, feature, CTA), decorative-layer (pseudo-elements, absolutely positioned ornaments, SVG art-direction layers), and motif system (stripes, grids, scan lines, grain, glows, repeated patterns).

When inspecting, always check: background, background-image, background-size/repeat/position/attachment, mask, mask-image, filter, backdrop-filter, opacity, mix-blend-mode, isolation, decorative SVGs, data URI / base64 backgrounds, and pseudo-element paint layers.

If an atmospheric pattern appears only in one component but clearly represents the site's broader visual language, elevate it into a motif token rather than leaving it inside that component.

Rule 9: Capture mood, not only implementation#

In addition to CSS facts, summarize the visual mood in plain language.

Examples:

• warm editorial minimalism
• futuristic terminal-industrial
• crisp enterprise dashboard
• soft gradient SaaS marketing
• playful geometric education product
• brutalist poster-like system

This mood description should align with the extracted tokens and motifs.

---

Browser tool#

Do not attempt to extract styles by reading static HTML source or stylesheet files alone — computed styles, CSS variable resolution, and theme state require a live browser context.

This skill ships a self-contained Python/Playwright script. Before running it, resolve SKILL_DIR using the Glob pattern **/skills/extract-design/SKILL.md (as described in Output Location above), then substitute it into the path below.

Setup (one-time):

bash

pip install playwright
playwright install chromium

Usage:

bash

# Light mode only
python3 {SKILL_DIR}/scripts/extract-styles.py https://example.com

# Light + dark mode
python3 {SKILL_DIR}/scripts/extract-styles.py https://example.com --dark

# Save to file
python3 {SKILL_DIR}/scripts/extract-styles.py https://example.com --dark --out /tmp/styles.json

For @keyframes extraction (required for animation system):

bash

python3 {SKILL_DIR}/scripts/extract-keyframes.py https://example.com --out /tmp/keyframes.json

The script outputs structured JSON with light and dark keys, each containing:

• cssVars — all CSS custom properties ( --*) from stylesheets
• colors — computed backgroundColor, color on html/ body/card elements
• fonts — computed fontFamily, fontSize, fontWeight on body, h1, h2
• button — computed styles on the first <button>
• backgroundImages — all elements with background-image !== none (patterns, gradients)
• accentColors — computed colors on links and accent/brand-classed elements
• typography — h1 size, weight, letter-spacing, line-height, color

---

Recommended extraction workflow#

Before starting: Open {SKILL_DIR}/references/extraction-checklist.md and keep it open throughout. Check off each item as you complete it. Use {SKILL_DIR}/references/style-specimen.html as your structural template when building Output C.

Step 1 — Characterize the page#

Summarize:

• minimal / editorial / dashboard / marketing / docs / product / playful / brutalist / glassmorphism / etc.
• density
• contrast
• tone
• motion intensity
• component complexity
• atmospheric character
• recurring motifs

Step 2 — Gather raw observations#

Collect all observed values by reading computed styles directly, not by inferring from class names or source code.

Required checks (run these before proceeding to Step 3):

1. Default theme: document.documentElement.getAttribute('data-theme') — record the actual value on page load
2. Body background: getComputedStyle(document.body).backgroundColor
3. Body color: getComputedStyle(document.body).color
4. Font family: getComputedStyle(document.body).fontFamily
5. CSS custom properties: iterate document.styleSheets to extract all -- variables with their actual values
6. Accent/brand colors: query key elements (links, buttons, badges) and read .color and .backgroundColor
7. Background patterns: query all elements for backgroundImage !== 'none' — record the full value including gradient stops and background-size
8. Transitions: read getComputedStyle(el).transition on buttons and interactive elements — record the exact easing function
9. Card/surface styles: read backgroundColor, borderColor, borderRadius, boxShadow on card elements
10. Dark mode: if a theme toggle exists, activate dark mode and re-read the above values
11. @keyframes: extract all @keyframes rules from stylesheets (see section 6b for method)

Record raw values first. Do not skip to naming or abstracting until all raw values are collected.

Step 3 — Normalize into primitives#

Reduce noise and create primitive tokens.

Step 4 — Map to semantic tokens#

Assign role-based names.

Step 5 — Build background and motif systems#

Identify:

• page base layers
• section atmosphere variants
• decorative overlays
• signature motifs/patterns
• hero atmosphere composition

Step 6 — Build component archetypes#

Identify reusable component families.

Step 7 — Derive interaction rules and extract @keyframes#

Summarize state transitions and motion behavior. If the site uses @keyframes (backgrounds, modals, loading states, hover effects):

1. Run {SKILL_DIR}/scripts/extract-keyframes.py or extract via browser console
2. For each keyframe, abstract into semantic description
3. Map to component archetypes where used
4. Add to manifest's motion.keyframes array
5. Add animation demo section to specimen HTML

Step 8 — Build the specimen HTML#

Create a general-purpose design reference page following the structure in {SKILL_DIR}/references/style-specimen.html. Save to {SKILL_DIR}/assets/theme/{name}-style-specimen.html.

The template uses /* REPLACE */ as placeholders for every CSS token value. You must replace every single one with a value measured from the target site. Search the output file for /* REPLACE */ before saving — if any remain, the step is not complete. Add or remove motif cards and background sample cards to match what was actually found.

Step 9 — Validate usefulness#

Ask:

• Could another AI use this to generate a new page in the same style?
• Does it capture the system rather than only one page?
• Does it include tokens, themes, components, states, motion, and code blocks?
• Does it include atmosphere, motifs, and animations (@keyframes)?
• Does the specimen HTML include an Animation System demo section if the site has @keyframes?

If not, revise.

Step 10 — Sync manifest and specimen#

Before saving, verify that the manifest and specimen HTML are consistent:

• Every component archetype in manifest.components must have a corresponding rendered section in the specimen HTML.
• Every component section in the specimen HTML must have a corresponding archetype in manifest.components.
• No field in the manifest should be an empty object {} or empty array [] — use null with a limitations note instead.

If they are out of sync, fix both files before finishing.

---

Required style manifest schema#

The structured manifest should generally follow this shape:

json

{
  "meta": {},
  "style_character": {},
  "primitives": {},
  "semantic": {},
  "background": {
    "page": {},
    "sections": [],
    "layers": [],
    "gradients": [],
    "patterns": [],
    "images": [],
    "overlays": []
  },
  "motifs": [],
  "themes": {},
  "motion": {
    "duration": {},
    "easing": {},
    "keyframes": [
      {
        "name": "animationName",
        "description": "What the animation does",
        "from": "opacity: 0; transform: scale(0.95)",
        "to": "opacity: 1; transform: scale(1)"
      }
    ]
  },
  "components": [],
  "responsive_rules": [],
  "accessibility_notes": [],
  "limitations": []
}

Note: If no @keyframes were found on the site, set motion.keyframes to null with a note in limitations.