Well no, none of them ?
This is what OP was talking about:
https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Nest...
No, he's not: https://news.ycombinator.com/item?id=46570846
Ignore it then, CSS nesting and layers are the real deal
Nesting is the bee's knees.
I still don't understand what layering is, and why you would use it.