CSS Corrector от Kauol

CSS Corrector lets you change the CSS of any website and keep those changes between visits.

Pick an element right on the page, edit its properties, and save everything as a preset that turns itself on only on the sites you choose.

What it does:

• Point-and-click element picker: hover to highlight, click to select.
• Choose what a property affects: only the element you picked, any class or id it carries, or a selector you type yourself.
• See the site's own CSS rules for that element sorted by specificity, so you can tell what is overriding what.
• Warns you when a class-based change also touches other elements saved in the same preset.
• Presets apply per site with simple masks like example.com or example.com/blog/*/edit.
• Turn off one preset or everything at once, without deleting anything.

Nothing is collected and nothing is sent anywhere. All presets stay in the browser's local storage.

Source code: https://github.com/susanin3/css-corrector