Style Engine – Custom CSS & JavaScript

Apply custom CSS and JavaScript globally or per domain. Local-only, lightweight, and fully user-controlled.

Style Engine lets you apply your own CSS and JavaScript to websites, either globally or for individual domains. It is designed for developers, designers, power users, and anyone who wants more control over how websites look and behave without modifying server-side code. Create simple visual tweaks, remove unwanted interface elements, adjust typography and spacing, test CSS ideas, or run your own JavaScript snippets directly in the browser. KEY FEATURES Global rules Apply CSS or JavaScript across all supported websites. Global CSS and Global JavaScript can be enabled independently. Per-website rules Create isolated CSS and JavaScript rules for individual domains. Each site can have its own code and independent CSS/JS enable controls. Live CSS updates CSS changes can be previewed directly on the active page while editing. Optional live JavaScript preview JavaScript can be previewed while editing in the popup. Live JavaScript preview can be disabled from Settings. JavaScript effect cleanup When supported live JavaScript changes are replaced or disabled, Style Engine can clean up common DOM, style, event listener, and timer effects without requiring a page reload. SPA navigation support CSS remains available across modern single-page application navigation. Optional JavaScript rerun behavior for SPA navigation can be enabled in Settings. Automatic saving Editor changes can be saved automatically while you work. Automatic saving can also be disabled if you prefer manual Save controls. Global and site-specific management Manage saved websites, edit existing rules, create new site rules, or remove rules from a dedicated Settings interface. Backup and Restore Export your complete Style Engine configuration to a local JSON backup and restore it when needed. Light and dark themes Use the system theme automatically or select a light or dark interface manually. Flexible feedback Choose between desktop notifications, inline messages, or silent operation for action feedback. Multilingual interface Style Engine currently supports: English German Spanish French Italian Dutch Polish Portuguese Russian Turkish COMMON USE CASES • Create custom dark or light styles for websites. • Hide banners, promotional areas, sticky elements, or other unwanted interface components. • Adjust fonts, colors, spacing, and page layout. • Add accessibility-oriented visual adjustments. • Create debugging or development overlays. • Run small JavaScript snippets for repetitive browser-side tasks. • Maintain different customizations for different websites. • Apply common CSS or JavaScript rules globally. PRIVACY AND CONTROL No tracking Style Engine does not collect browsing history, analytics, or usage telemetry. Local storage Your settings, CSS, JavaScript, and website rules are stored locally in your browser. No browser sync storage Style Engine does not upload or synchronize your saved rules through browser sync storage. No remote code Style Engine does not download or execute JavaScript from remote CDNs or external code sources. User-controlled code The extension executes code entered by you into Style Engine. Website permissions are requested when needed Site access is requested when you enable functionality that requires access to a website. Global rules may require broader optional website permission. Your rules remain under your control and can be enabled, disabled, edited, exported, restored, or removed at any time. LINKS Website: https://glitchid.com/products/style-engine/ Documentation: https://glitchid.com/products/style-engine/documentation/ Privacy Policy: https://glitchid.com/privacy/style-engine-privacy/ Terms: https://glitchid.com/terms/style-engine-terms/ Support: support@glitchid.com Publisher: Glitchid