It’s hard to explain because most web development solves these problems with CSS in JS with JS runtimes. One use case I have is what I call “responsive variants

It’s hard to explain because most web development solves these problems with CSS in JS with JS runtimes. One use case I have is what I call “responsive variants”; basically a way to apply a variant’s styles on a component instance (speaking abstractly here; could be react, vue, whatever) within any arbitrary styling context without duplicating CSS or resorting to something that applies CSS with a JS runtime. I work on a web development platform for a living and this is the sort of thing that would be good for us; if you don’t want your website to wait for JS to render content correctly and you want to keep your CSS bundle small, there aren’t many good options.