[benforreal]

In the instance of Predix (I peripherally worked on that during my time at GE) and likely EA and every other large Web Component ecosystem you're thinking of, that's desired behavior. The real want is a design system such that things look consistent, but as design systems are CSS only, they aren't smart enough for interactions that require JS. So then the need for a design system becomes a need for components of some kind that include the design. You're looking for components with more adaptable design, but that's just not the intention of these ecosystems. If done with that goal, yes CSS vars take you a little bit of the way, but I think we'll see more power coming to help out soon with Shadow Parts/Theme, CSS Modules, and Scoped Stylesheets. But really, just styling a background? If the component author just left the background: none, you could do whatever you wanted from the outside. It just takes planning - even without the Shadow DOM you still need to plan for proper themeing.

[winterthedeep]

"styling a background" is just an example - I admit it is a bad one (glad I don't work in frontend anymore). I will read about CSS Modules and the other stuff you mentioned. Thank you.

[benforreal]

Sure thing! Those things are def up and coming, and I'll admit I haven't looked into them so much yet, but they are being designed to solve this very problem. I don't think that Web Components are the tool to solve every problem, but I've been a fan for a while (so much so that I'm writing a book)