Toggle Website Colors (Global) от Manuel Reimer

This addon adds a button to toggle the website colors set by the author.

This setting affects all open websites!

To change the colors, set when disabling the author-defined colors, you have to edit the Firefox settings:

• Open the Firefox preferences
• Be sure "General" is selected on the left
• Click the "Colors..." button in the section "Language and Appearance"
• Change the color settings to your liking