What's the use of night mode? Even if someone needs to browse web in the darkness (which is a bad idea anyway), it should be implemented somewhere in the OS, not in applications.
OS-level utility needs APIs that are not there in case of Android. All night-mode apps for Android are just a reddish overlay. It often falls apart when you something can't go through the overlay like AFAIR system passwords. I tried to use apps, but met with this wall several times.
Android did have a night mode, but it was experimental and removed in later versions. So other than alternative ROMs there's nothing there.
