Just took a closer look at this. Yes they are using libsass. They are using it with grunt and grunt-sass (https://github.com/sindresorhus/grunt-sass https://g

Just took a closer look at this. Yes they are using libsass. They are using it with grunt and grunt-sass (https://github.com/sindresorhus/grunt-sass https://github.com/sindresorhus/grunt-sass), which uses node-sass (https://github.com/andrew/node-sass https://github.com/andrew/node-sass). There are other implementations available: https://github.com/hcatlin/libsass/wiki/Implementations https://github.com/hcatlin/libsass/wiki/Implementations