OnePlus
Enable Dark Mode via System Tone auf OnePlus
OnePlus phones running OxygenOS do not offer a standalone Dark Mode switch in the main settings list. Instead, the dark design is controlled through the system tone, a setting that defines the overall color scheme applied across the interface.
This tone setting affects the home screen, app drawer, notification shade, and most system menus at once. Switching it to dark replaces bright backgrounds with dark surfaces and adjusts text contrast accordingly, while switching back to light restores the original layout.
To change it, open Settings ➔ Customization ➔ Tone ➔ Dark ➔ Save. The change applies immediately without a restart.
If only some apps stay bright after switching, that usually means those apps manage their own theme setting separately from the system tone. In that case, check the individual app's own display settings instead of the system menu.
Battery savings from dark design are mainly noticeable on OnePlus devices with OLED-type displays, since dark pixels use less power than bright ones. On other display types, the visual change happens but battery impact stays minimal.