I just merged in a change that will move tag names to data attributes.
https://github.com/discourse/discourse/commit/8ff83d174ee518a2f04721d3b3088924e242e648
so now to style a tag named box you’d use this
[data-tag-name="box"] {
// styles here
}
I went with a data attribute because it reduces the possibility of future class collisions to 0.