Consider an API which removes sprite selectors

Rather than mapping sprites to CSS, could we map each sprite to a class, and then have a utility to add that class to a component?

It's a bit tricky with pseudo classes. We might have to create a class for each pseudo class.

For example, a `main-bg-hover` class might have a selector `.main-bg-hover:hover`. So adding the `main-bg-hover` button would set the main background as that element's background when hovered.

It get's more complicated with composed pseudo selectors, like active input handles. Browser specific selectors are annoying too.