Disallow empty rules

What the hell is going on here? I followed this link from a VS CSS error, and I find an empty wiki page? Why isn't there a proper discussion or explanation of what the problem is? Is this project being run by clowns?

I am seeing VS throw a false csslint error when I declare a :root rule with defined color variables, so clearly it isn't an empty rule. I am seeing this a bug in csslint, because it doesn't properly recognize a documented feature of css.