Stylus is a fork of Stylish that can be used to redesign the web. The objective in creating Stylus was to remove any and all analytics, and return to a more user-friendly UI. This is why we named the extension with an "us" ending, as in the actual users.
Stylus allows you to change the display of any site on a consistent basis. It's easy to add multiple versions if a comparison is needed. The most convenient thing is that the changes are pulled up in real time.
It is also great for selecting and changing CSS objects right on the page, keeping styles in a separate place. Stylus immediately detects whether there are syntax errors in CSS.