Susuto

All these are good accept for: 3. Use whitespace wisely

Readability is far more important than “page weight” seeing that you can add gzip compression and several other techniques after the fact. I wish people would stop encouraging people to write CSS like in that example - all on one line - it’s barely readable, and a pain to maintain.

You’d be beaten with a large blunt object if you wrote code like that (even javascript) for the same reasons it’s not a good idea to do it with CSS (unless everyone on the team is using some sort of WYSIWYG CSS editor)

Aside from 3, they are good tips.