The userchrome.css file lets you customize the Firefox interface deeply. While very powerful, any changes will require a restart of the browser to take effect.
This Firefox extension adds a new button to your toolbar that allows you to toggle custom userchrome.css styling on-the fly. The magic happens by including special CSS selectors in your user styles. Manipulating those selectors allows you to enable/disable up to three of your modifications on-the-fly.
The addon accomplishes this by changing the browsers 'title prefix' attribute. Don't worry! By using invisible UTF-8 characters by default, you won't even notice a thing! Toggle a single style or select up to three styles to toggle in a drop-down menu. Hardcore keyboard users can even use customizable keyboard-shortcuts.
Toggle a single style with the toolbar button
Switch between different styles
Select multiple styles to be active together
Sample of the settings for a single toggle
- Report issues or feature requests in the bug tracker