SMACSS is a set of recommendations for reducing CSS bloat in large web applications. Compass is a library of convenience classes, and the others you mention ar

SMACSS is a set of recommendations for reducing CSS bloat in large web applications. Compass is a library of convenience classes, and the others you mention are preprocessors. Apples and oranges. SCSS and Less are similar enough that porting code between them is usually just a matter of changing a few symbols and keywords. Compared to the fragmentation of the rails ecosystem I don't consider this too overwhelming.