css and/or SASS + (sibling) selector upwards [duplicate]

Answer 1

SASS support all CSS3 selectors. Sibling + is one of them. But it does not bring some extra features. It means you can do

first {
  + second { 
     font-size: smaller;
  }
}

But you can't impact a parent with it ...

Ps : it seems to be a features of CSS4 :)