Thanks for the kind words!
That's a really good point about the query selector.
The compiler uses dot notation to store a reference to each ruleset which looks like this "element.class.modifierClass". The reason for the dot in multiple classes was more for implementation convenience than anything else (never a good reason).
I much prefer your suggestion (space between multiple classes versus a dot), and having looked at the code it shouldn't be that difficult to support. I will create an issue in GH.
Thanks again!