There's no real way to translate the classic theme "as designed" to hi-DPI systems, AFAIK; let alone to allow it to freely morph between desktop and tablet interaction paradigms when you dock/undock a two-in-one.
You could in theory design a modern UI that resembles the classic UI, but it wouldn't really be "the classic UI". A large part of what makes the classic UI have the particular look it does is that it has custom constraint-layout logic for each control, the outputs of which are fed as parameters into the arbitrary hand-written GDI draw-call logic used to draw each control.
Some of the more interesting controls have Turing-hard constraint logic, which just can't be replicated in non-Turing-complete constraint-layout systems like XAML or CSS. (You can get close, but it requires using huge hierarchies of layout nodes with tons of overhead, where the Windows UI actually got by with very few.)