Give me dark mode in all apps and I’ll live happily ever after. I live by this aesthetic motto, and even though the pace at which developers have been adopting dark mode has been commendable, Google has so far shied away from bringing it to its own productivity apps. That changes now, with the arrival of dark theme for Docs, Slides, and Sheets on Android.
Google has begun rolling out dark theme for the three apps, but it might take more than the usual 15-day span for the feature to appear. No admin control will be required to enable the dark theme, and it will be applied automatically in Docs, Slides, and Sheets apps based on the default system settings.
However, users can choose to override this feature and enable/disable it individually for each app by going to Menu > Settings > Themes > Dark. And while you are working with dark theme enabled, there will also be an option called ‘View in light theme’ to see how a particular file looks in light theme.
Source: Google Blog