StyleKit

StyleKit is a browser extension that lets you customize any website's appearance instantly. Pick elements visually, tweak colors and fonts, or write raw CSS -- your changes are saved automatically and persist across visits.

Built on Stylebot by Ankit Ahuja, StyleKit is a complete modernization with a Catppuccin Mocha dark theme, plain-English labels, guided onboarding, security hardening, and full Manifest V3 compliance.

Features

Visual CSS Editor

• Point-and-click styling -- select any element on the page, then adjust fonts, colors, spacing, borders, and visibility through an intuitive panel
• Multi-select elements -- hold Shift and click to add elements to the selector (e.g., h1, h2, h3)
• Element search -- find elements by CSS selector, tag name, class, ID, or text content
• Plain English labels -- "Text Size" instead of font-size, "Fill Color" instead of background-color
• 1,500+ Google Fonts -- full Google Fonts catalog with search/filter, cached for 1 week
• Gradient generator -- visual linear/radial gradient builder with live preview, color stops, and angle control
• Accessibility overlay -- shows ARIA role and WCAG contrast ratio (pass/fail) in the element tooltip during inspect
• Responsive preview -- test styles at Mobile (375px), Tablet (768px), Laptop (1024px), and Desktop (1440px)
• Color preset palette -- 15 quick-pick colors above the color picker
• Box model widget -- visual margin/padding/border editor with Catppuccin dark theme
• CSS variables panel -- edit custom properties on the selected element
• Computed styles view -- see the current effective styles at a glance

Code Editor

• Full Monaco editor -- syntax highlighting, autocomplete, word wrap
• CSS/SCSS mode toggle -- switch syntax highlighting between CSS and SCSS
• CSS linting -- real-time error detection (missing braces, invalid values) with relaxed rules for modern CSS
• Live preview -- CSS changes apply instantly as you type
• Diff view -- see what changed since you started editing
• Copy / Export / Reset buttons in the footer

Popup

• Find Styles -- search UserStyles.world for community styles matching the current site
• Style auto-update -- installed styles older than 24h are checked for updates; one-click update button
• Hover preview -- preview any style live on the page before installing
• Install with one click -- styles are saved and applied immediately
• Toggle installed styles -- enable/disable individual installed styles
• Auto-load mode -- thumbnails pre-fetched in the background for instant popup loading
• Restricted page detection -- shows "Not available on this page" on chrome:// and system pages

Site Recipes & Snippets

• 20+ pre-built recipe packs for YouTube, Reddit, GitHub, Twitter, and more
• Universal recipes (dark mode, compact layout, etc.)
• Snippet library with ready-made CSS effects

Sync & Backup

• Google Drive sync -- automatic bidirectional sync across devices
• GitHub Gist backup -- export/import via private Gist with Bearer token auth
• JSON export -- versioned format with metadata ({version, app, exportedAt, styles})
• CSS export -- all styles as a single .css file with URL comments
• JSON import -- validates structure, supports both versioned and legacy formats

Readability Mode

• Distraction-free reader view with customizable font, size, width, line height, and theme
• Works on SPAs with automatic re-application on navigation

Other

• One-click hide element -- right-click context menu
• Onboarding walkthrough -- 3-step guided tour on first use
• Undo toast -- visual feedback after each change with Undo button
• Keyboard shortcuts -- fully customizable (Escape closes editor from any context)
• Dark mode generation -- automatic dark theme for any page
• Grayscale mode -- reduce eye strain
• 15+ language translations
• Two-click delete confirmation -- prevents accidental style deletion

Installation

From Release

1. Download StyleKit-v1.1.0-chrome.zip from Releases
2. Unzip the file
3. Open chrome://extensions
4. Enable Developer mode
5. Click Load unpacked and select the unzipped folder

From Source

git clone https://github.com/SysAdminDoc/StyleKit.git
cd StyleKit
npm install
npm run build

Then load the dist/ folder as an unpacked extension.

Firefox

npm run build:firefox

Load from firefox-dist/.

Development

npm run watch          # Dev build with hot reload (Chrome/Edge)
npm run watch:firefox  # Dev build (Firefox)
npm test               # Run tests (8/8 suites, 76 tests)
npm run lint           # ESLint check
npm run lint:fix       # Auto-fix lint issues

Settings

Tech Stack

• Vue 3 + Vuex 4 + TypeScript
• Vite 5 (multi-entry Rollup build)
• Bootstrap 5 + bootstrap-vue-3
• Monaco Editor (embedded iframe)
• Vitest + jsdom for testing
• PostCSS (cssnano, rem-to-pixel)
• Catppuccin Mocha dark palette

Architecture

src/
  background/     Service worker (MV3, ES module)
  editor/         Content script - visual CSS editor (Shadow DOM)
  inject-css/     Content script - applies saved CSS (document_start)
  popup/          Browser action popup
  options/        Extension options page
  readability/    Reader mode (Shadow DOM)
  monaco-editor/  Code editor iframe
  sync/           Google Drive + Gist sync
  css/            PostCSS utilities
  dark-mode/      Dark mode CSS generation
  highlighter/    Element overlay for inspector

Privacy

StyleKit collects nothing. No analytics. No tracking. No telemetry. Period.

Your styles are stored locally in chrome.storage.local. Cloud sync (Google Drive, Gist) is opt-in and goes directly to your own account -- StyleKit never sees or stores your data.

Security

StyleKit includes comprehensive security hardening:

• Sender validation on all background message handlers
• textContent for all CSS injection (never innerHTML)
• Origin-restricted postMessage (never wildcard *)
• URL validation for thumbnail fetches and CSS imports (HTTPS only)
• RegExp safety with try/catch to prevent ReDoS
• Content-type validation on CSS imports

Related Tools

Credits

StyleKit is built on Stylebot by Ankit Ahuja, licensed under MIT.

License

MIT