Sorry, of course it must be navigation-ICONS, not -items

Hello from Germany,
I just installed Opera Mini on my Samsung Galaxy S4 and tried to open my website http://www.star-koerpergroessen.de, to check how it works there. I built the homepage with Wordpress Theme Twenty Fourteen. Unfortunately the navigation doesn't seem to be alright, the navigation-items are missing and the page needs very long to load. I thought, it's my mistake, because I modified the theme a little bit. But now I found the same wrong display on the original Twenty Fourteen Theme: http://twentyfourteendemo.wordpress.com. In other browsers the pages load fast, and navigation is ok.
Does anybody know something about this, maybe it is a known bug?

Thanks a lot

Andreas