Could you elaborate? How does it not scale? It's using bootstrap for styling, so there's that. Me and a couple of lecturer peers have been using it in lectures for classes of all sizes which includes different kinds of beamers. As you stated, my machine will also auto-scale resolution in this scenario. If all else fails, there's Strl++/- (;

I'm also using it on OS X and Debian. Both work well. And as is recognizable from the git commit history - there's not much that needs to be done over the years to keep it going. Exactly my kind of HTML system - dead simple, no dependencies, works also years later^^