Kickstart

Kickstart's CSS is only 80kb and even smaller when you roll your own from the Sass mixins. Not only is the Kickstart JS smaller than Bootstrap and Foundation, it also doesn't require jQuery--drastically reducing page load times. Kickstart has been used in production websites for over three years. Kickstart is a library, not a framework. This means you only use the CSS you need instead of slowing down your site with a complete UI library. Look how easy it is to create this Navbar. Most components in Kickstart require only one mixin to bring markup to life. For users preferring a static CSS file, simple CSS classes are available to quickly write up components. The Kickstart documentation can be toggled between static- and mixin-usage. Kickstart has a lot of components, but it's also extendible.