Bootstrap is a CSS toolkit from Twitter designed to kickstart development of web apps and websites. It includes base CSS and HTML for typography, forms, buttons, tables, grids, navigation, and more.

Bootstrap is built with Less and was designed to work out of the gate with only modern browsers in mind.

You can use Twitter Bootstrap in one of two ways: just drop the compiled CSS into any new project and start cranking, or run LESS on your site and compile on the fly like a boss.