While I like the idea of lightweight UIs, this one seems to have some problems[0] in Firefox 55.0, the responsive mode view looks better but still has some issu

While I like the idea of lightweight UIs, this one seems to have some problems[0] in Firefox 55.0, the responsive mode view looks better but still has some issues with the menu. I thought I had failed to download a stylesheet at first but the desktop view actually has all the assets for the page. [0]: http://imgur.com/a/On8hZ http://imgur.com/a/On8hZ