Milligram, Minimalist CSS Framework [↗]
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 designed for better performance and higher productivity with fewer properties to reset resulting in cleaner code.
I really like the look of this one, it could be a nice replacement for when I reach for Bootstrap, but know that I only want/need a small amount of it.