less – The dynamic stylesheet language.
LESS extends CSS with dynamic behavior such as variables, mixins, operations and functions. LESS runs on both the client-side (IE 6+, Webkit, Firefox) and server-side, with Node.js.
Ender – a full featured package manager for your browser.
Bootstrap is Twitter’s toolkit for kickstarting CSS for websites, apps, and more. It includes base CSS styles for typography, forms, buttons, tables, grids, navigation, alerts, and more.