Hello,

1) You have cross-origin issue as you can see https://www.screencast.com/t/BepX9XAmF. In order to fix this you need to use this solution https://wpvkp.com/font-awesome-doesnt-display-in-firefox-maxcdn/. It will work fine for all browsers. 

2)  We have tested speed of your website via Gtmetrix and  in order to improve speed performances, I marked what should be done from server side.

What you or your hosting provider should do in .htaccess file is described here:

http://gtmetrix.com/enable-gzip-compression.html

http://gtmetrix.com/leverage-browser-caching.html

Also you need to optimaze your images with some available tool, since it takes to much time to load as you can see here https://www.screencast.com/t/AxnP57NRV

Basically, minor modifications of this file would help you to get better grade related to speed of page loading

Thanks