This tip is for those who loves dark theme but having trouble with some apps by which dark mode can't be applied by its own, like SnapChat as an example.
If you have a Samsung or any other android flagship phone, then go to settings > about phone > build number (touch it 6 to 7 times) > once you are a developer, open developer options and search for "force dark mode" then enable it.
And you done it, now force mode will be applied to all apps even if it doesn't support it.
