Expressive CSS follows the atomic approach to writing lightweight, scalable CSS with utility classes that are easy to write and understand.
To get started, download the project and look at the Starter Styleguide. This project has been built with SASS and uses NPM with a basic build script to compile. You could ditch all that and use the pre-minified css in the stylesheets directory. Feel free to use all, some, or none of it as you see fit.