Expressive CSS is not intended to be a library or framework, but rather a presentation of an approach to writing lightweight, scalable CSS using utility classes that are easy to write and understand.
For more info, go to the Expressive CSS Project Page.
To install download the project or run:
npm install expressive-css
Or, to build the project with every save:
npm run watch
This project contains some useful SASS mixins, such as utility generators. Check them out in the css/sass/_mixins directory.