Hi,
I think, this is a bug!
If your site is reachable by port 80 and 443, you should fix your code to load external content in the same scheme way(http/https).
Firefox 23 block this for security reasons. Check google for “Blocked loading mixed active content”.
Please fix the source code in the package!
you need only to fix the scheme:
wp_register_style( 'interface_google_font', 'http://fonts.googleapis.com/css?family='.$interface_google_font_load .':400,700italic,700,400italic');
to
wp_register_style( 'interface_google_font', '//fonts.googleapis.com/css?family='.$interface_google_font_load .':400,700italic,700,400italic');
Regards
Konrad Lorentz
