Dark Theme any App
I absolutely love dark themes in my apps. Not only is it easier on the eyes, but having a true amoled black theme could save you battery life on certain devices like the Galaxy S8. Unfortunately, not every app comes with a dark theme option. So if you want to dark theme any app on your device you will need to use the theme engine called Substratum. Substratum could give you a dark theme Instagram, dark them Facebook, dark theme Inbox, etc.