Dark Mode for Apps allow users to use their Android devices in a darker mode than the default "light" mode. As a result of this feature, your Android device will not be able to see any applications especially those that require attention from the user like email and games. Instead, the user will see a black screen that says "Network connection failed."
This feature works for all applications that use the Android framework including networking, media and instant messaging applications. It is a special feature that enables users to have a fully dark mode for apps and use it even while their device is off. If you want your Android device to work normally when you are not around and want to continue using your applications even while the screen is off, then apply the "night" feature to your application. This will make your Android device act normal and will not give you any error messages or other complications.
For further details, just go to the Google Android Studio app and find the "Settings" option. You should find an option named "System Settings" and click on it. Once you are done with that, select the "Light" or "Night Mode" and set the value to "true" to turn on the Dark Mode for apps feature and if you want to turn it off, simply do the same as mentioned above.