[Izkata]

They're at least compatible then.

More important to my point, back in 2015/early 2016 and before, you more likely than not had to somehow manually include the CSS for a given component library into your page. Right about the same time CSS Modules got popular, the CSS from libraries started getting included automatically in the compiled CSS file (whether by way of CSS Modules or something else that at least doesn't conflict with it).

I remember this part of the timeline pretty distinctly because late 2015 is when we started a new project in React, and struggled with how to reliably deal with CSS for several months.