Twitter recently open sourced a new toolkit called Bootstrap, which was developed by Twitter engineers in order to overcome challenges in developing the frontend of their own website.The open sourcing marks the 1.0 release of the library.
This tiny 6kb (compressed) library is essentially a collection of CSS styles that enable rapid prototyping and development of clean interfaces for applications.
Twitter’s Bootstrap library includes a number of Less files that each deal with different areas of UI design: reset.less, preboot.less, scaffolding.less, type.less, patterns.less, forms.less, and tables.less. These when compiled give one combined CSS file.
Twitter has places the library on GitHub so that the open soruce web developer community can get involved in the development fro here on. You can download / fork BootStrap from here, or check here for other open source projects by Twitter.