CSSO (CSS Optimizer) is a CSS minimizer unlike others. In addition to usual minification techniques it can perform structural optimization of CSS files, resulting in smaller file size compared to other minifiers.
npm install csso
Try it out
Initial idea — Vitaly Harisov (email@example.com)
Implementation — Sergey Kryzhanovsky (firstname.lastname@example.org)
English translation — Leonid Khachaturov (email@example.com)