stylextension by Firefox user 13014860

This very small WebExtension will allow you to inject a custom CSS stylesheet into all sites you visit making you the stylist of your web.

Features include:

• Inject a custom CSS stylesheet into all websites.
• Override the injected stylesheet for each host individually.
• Temporarily toggle functionality for the current tab.
• See the effects of your changes to the stylesheet while you make them.

The default key combination for toggling functionality for the current tab is ALT+SHIFT+I. Firefox currently lacks a way to change this default combination.

Note that because this is a WebExtension it will not work on sites WebExtensions can't inject CSS into.