In addition to Night Light you can also enable Dark mode or the Windows 10 Dark theme.
The Settings application itself will immediately turn dark, as will many other “Universal Windows Platform” applications. However, it’s up to each developer to support the dark theme, and some applications will continue using their normal colors.
This option also doesn’t affect desktop applications, including Windows 10’s File Explorer, which will remain white.
For example, we installed UxStyle and the Windows 10 – Dark Edition visual style. There are many other dark themes you could choose. A theme like this one makes File Explorer and other applications look darker and fit in better, although there are still parts of Windows desktop applications that themes don’t (and can’t) modify. Just make sure you back up before installing something like this, as you’re messing with system files.
Like many parts of Windows 10, the new dark theme–or dark “app mode”–feels incomplete. Microsoft could include a dark theme option for Windows desktop applications and the interface would look more cohesive. Perhaps Microsoft plans on replacing File Explorer with a new, Universal Windows Platform-based file manager in a future update to Windows 10. For now, though, this is what we’ve got.