xCSS : xCSS bases on CSS and empowers a straightforward and object-oriented workflow when developing complex style cascades.
Milligram : Milligram provides a minimal setup of styles for a fast and clean starting point. Just it! Only 2kb gzipped! It's not about a UI framework. Specially ...
lit : a ridiculously small responsive css framework
Pure : A set of small, responsive CSS modules that you can use in every web project.
