Firefox has both a dark theme and a light theme. It’s up to a user to decide which one they want to use. It’s separate from the Windows 10 dark and light themes which means, it won’t change with the Windows 10 theme you’ve set. Dark themes in a browser usually help make reading at night a better experience. Time-Based Theme Changer is a Firefox add-on that can automatically switch to the dark theme at night in Firefox, and back to the light or default theme in the morning. It’s built for Firefox for the desktop however, the developer says you can use it on Firefox for Android if you install a light and dark theme in it first.
Dark Theme At Night
Install Time-Based Theme Changer and tap the Ctrl+Shift+A keyboard shortcut to go to the add-ons manager. Here, click the Options button next to Time-Based Theme Changer.
By default, Time-Based Theme Changer changes to the default theme at 8:00am and to the dark theme at 8:00pm. If that time suits you, leave the add-on’s settings untouched. If not, change the morning and night time. Additionally, you can also have Firefox switch to the Light theme in the morning instead of the default theme.
Time-Based Theme Changer checks the time every 5 minutes so, once you install the add-on you can wait for five minutes for it to check the time and change the theme automatically, or you can click the ‘Manually check time’ button to force the add-on to do a time check. If it’s time to change the theme, it will do so.
Although Firefox has other themes besides the light, dark, and default one, the add-on only supports these three. If you install a theme, it might show up since the developer says installing themes in Firefox Android will be enough to get this add-on to work in the mobile version of the browser.
Firefox Android
To get this to work on Firefox Android, you need to find a theme that is compatible with the latest version of Firefox. Even then, your options will be limited. It seems the add-on doesn’t detect all themes installed in Firefox. We don’t know how it draws a distinction but it appears that most themes do not register with this add-on. We were able to find one theme called White Damask that works with it but it’s a light theme and you still need to find a dark theme to go with it. You can also try waiting a month or two to see if new dark themes are added to the Firefox add-on store and then try your luck with them.