This page is intended for Joomla Bug Squad members.
Joomla 3.0 is shipped with a LESS compiler to generate default template and bootstrap CSS files from LESS files.
The css generation wrapper script, LESS compiler, and other similar build tools are located in the build directory. The build directory is only available from a GitHub clone; it is not included in an official Joomla release.
To generate the CSS files you will need to execute the generation scrips as a CLI application.