.less building blocks are located in
media/jui/less/. The template specific
.lessfiles are located in
The CSS generation wrapper script, LESS compiler, and other similar build tools are located in the
build/ directory of the Joomla source located on GitHub. Refer to Git_for_Coders for more information on using GitHub. The build directory is only available from the Joomla source, it is not included in an official Joomla release.
To re-generate all the CSS files from a Joomla core distribution, you will need to execute the generation scripts as a CLI application.
cd joomla-cms/build c:\xampp\php\php.exe generatecss.php
To compile less files for your own template, you will need to take a copy of the
generatecss.php script and adjust it to suite your template.
The LESS compiler used for the Joomla core for code style consistency is obtained from leafo.net/lessphp.
If you're working on your own template you can use any compiler you like.