Run PurifyCSS on a single saved edited down webpage

I'm trying to figure out what changes were made to a particular menu to make it responsive. I saved the page off, and edited the stuff out of the bottom. I cannot get node.js/purifycss to run on my system. I just need the results from this single page, which I will zip up and send to you. Freelancer doesn't allow me to state this specifically, but I have $30 budgeted for this job. (And if you know purifycss, it'll probably take you 10 minutes.) I just need to know the specific styles used in their version of the menu, so I can adapt those styles to our regular website.