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.