CSS Pro

Designers and developers who want to try design changes on a live website today are stuck with built-in browser DevTools, which show computed CSS buried in noise rather than the actual applied styles, and require manual conversion between units like px, %, and em. Agencies prototyping design changes for clients have no fast way to show results in real time during meetings. Making quick visual experiments, testing new fonts, copy, layouts, or colors on a real page usually means digging through code, guessing values, and losing track of what was changed. There is also no simple way to share a set of CSS tweaks with a teammate or client, or to hand those changes to a developer to apply back into the actual codebase.

CSS Pro is a browser extension (Chrome, Firefox, Safari) that lets users visually edit the CSS of any website with no library, plugin, or code change required. It shows only the applied CSS on hover, offers a complete background and layer editor, a font previewer with 2,000+ fonts, inline text and element editing, unit conversion between px/%/em/rem/calc, color pickers and eyedropper, a ruler, an asset extractor, and a site-wide color palette tool. It includes an HTML Navigator for editing hidden elements, a responsive mode, and toggles for pseudo-classes like :hover. An AI assistant built on models like Claude Opus 4.5, ChatGPT 5.2, and Gemini 3 Pro can edit CSS on request, with changes shown as apply/undo diffs. Users can share their edits via a link with a before/after toggle, or copy a prompt that an LLM-based coding tool like Cursor can use to apply the CSS changes directly to the source codebase.