I find tha the library-style "button" "red" "blue" "big" example prevents me from having to flip over and maintain CSS with every HTML change. Yet your first e

I find tha the library-style "button" "red" "blue" "big" example prevents me from having to flip over and maintain CSS with every HTML change. Yet your first example has everyone editing CSS files and appending new classes to it all the time, which in my experience is the fastest way to end up with unmaintainable CSS. Mixins sounded good to me at first, but I've only experienced less maintainability when the CSS was too clever.