Install on Chrome

Three steps, about ninety seconds. No account, no signup. You will be inspecting CSS on whatever page you have open.

1. Add to Chrome

Open the WhatTheCSS listing on the Chrome Web Store and click Add to Chrome, then confirm. Chrome shows the exact permission set: activeTab, scripting, storage, clipboardWrite, and alarms. No host permissions — so there is no "read data on all websites" warning.

2. Pin the icon

Click the puzzle-piece extensions button in the Chrome toolbar and pin WhatTheCSS so the {W} icon stays visible. You can drag the in-page toolbar anywhere later; its position persists.

3. Activate on any page

Open any website and click the toolbar icon. A small scanning bar drops in at the bottom of the viewport. Hover any element to see its authored CSS.

What next

Walk through a real inspection on your first inspection, or jump to the keyboard shortcuts.