I was also torn between making it confusing and providing an example. I think the problem is nobody reading the documentation knows what "modifier class" means. This is also how the styleguide on github works (omitting the variable reference), so I figured it was good to follow that. Also, anyone doing CSS can see that the modifiers are class names so it should be obvious where to put it. I was also toying with the idea of replacing the variable with `{class}` as a placeholder indication. What do you think about that?