Built-in themes in Firefox - alternative to complete themes

Complete themes have been replaced by built-in themes with lighter and darker color schemes.

You can enable one of these built-in themes by following these steps:

1. Click the menu button , click Extensions and themesExtensions and Themes and select Themes.
2. Click Enable next to the desired theme.

   

Additionally, thousands of lightweight themes are available from addons.mozilla.org. For more information, see Use themes to change the look of Firefox.