Today, Twitter's developer blog officially released Bootstrap 2.0, and the source code has been published on GitHub.

Bootstrap is an open source toolkit for front-end development launched by Twitter. It is a CSS/HTML framework developed by Twitter designer Mark Otto and Jacob Thornton. Bootstrap provides elegant HTML and CSS specifications. It is written by the dynamic CSS language Less, and has many similarities with Blueprint, the CSS framework. Bootstrap has been very popular since its launch and has always been a popular open source project on GitHub, including NASA's code.nasa.gov and MSNBC's Breaking News.

A major improvement of Bootstrap 2.0 is the addition of the response design feature, which is not supported in 1.0, which makes many developers complain. In order to provide a more responsive design solution for mobile devices, Bootstrap 2.0 uses a more flexible 12 bar grid layout. In addition, it has updated some progress bars and customizable image thumbnails, and added some new styles. It is worth noting that Bootstrap is a very lightweight framework, and 2.0 is only 10KB after compression.

For more details, please refer to Twitter's official guide and demonstration examples.