If you download the source, Bootstrap is all Less[0] with an official Sass port[1]. For v4 they're moving to Sass too.[2] :) [0] http://getbootstrap.com/css/#l

If you download the source, Bootstrap is all Less[0] with an official Sass port[1]. For v4 they're moving to Sass too.[2] :) [0] http://getbootstrap.com/css/#less http://getbootstrap.com/css/#less [1] https://github.com/twbs/bootstrap-sass https://github.com/twbs/bootstrap-sass [2] http://blog.getbootstrap.com/2015/08/19/bootstrap-4-alpha/ http://blog.getbootstrap.com/2015/08/19/bootstrap-4-alpha/