Sorry, I don’t think I was clear with my question. By looking at your installation tutorial, After it is enabled on the admin side either in hamburger menu or on the header, it looks like each individual user has to go to their preferences and enable/add the light/dark color schemes. Otherwise it does not work for a new user / someone not logged in. So my question is:
Is it possible to implement the color scheme site wide rather than on a user-to-user basis.
Your photo is below for reference
