Enable Firefox dark mode on desktop To activate Firefox dark mode on Windows, macOS or Linux, open the main menu, click 'Customize' and choose 'Dark' from the 'Themes' drop-down menu at the bottom of the page.
Enable Firefox dark mode on desktop To activate Firefox dark mode on Windows, macOS or Linux, open the main menu, click 'Customize' and choose 'Dark' from the 'Themes' drop-down menu at the bottom of the page.