atf (above-the-fold) prints out above-the-fold css for whatever site you want.
PS: Doesn't work yet for styles loaded under SSL ¯_(ツ)_/¯.
It uses the CriticalCSS snippet from Paul Kinlan (Learn more about above-the-fold css here) with some tiny modifications on top of PhantomJS.
First, make sure PhantomJS is installed. This module expects the phantomjs binary to be in PATH somewhere. In other words, type this:
$ phantomjs
If that works you are good to go.
$ npm install --global atf
$ atf --help
MIT © Cleber Dantas