Facebook started to test out the newly redesigned dark mode (Still in Beta) for desktop, as announced in the last spring at the f8 developer conference.
However, you will need to use the new interface to keep dark mode enabled. New interface also featured with a cleaner interface, bigger fonts and quick loading time.
How to Enable Facebook Dark Mode on Desktop
01). Login to your account and click the arrow button.
02). Select Switch to New Facebook for the new Interface.
03). You will get a new Welcome window for your new interface. Press Next.
04). Choose a Theme and press Get Started.
05). Go to settings arrow and toggle between dark and lite modes.
6) If you don’t like the new interface, you can switch back to the classic interface by pressing the Switch to Classic Facebook in the settings menu.
7) Finally, you can leave feedback about your experience with the Beta version of the new interface.
Note : This is a one time feedback option.