Best approach to benefit from CSS performance enhancements

Great question, and something I think I'd like further clarification from our engineers on.

But, what I takeaway from that documentation, is that it is the CSS selectors that matter; not the file names. The page folder itself inside of the skin is technically not part of the core framework, so I don't think any special consideration is given to those files, it's just for your convenience.

Every page has the page name as a class applied to the body tag, which you can use in your CSS/SASS to target just that page.