Site error on iPhone


So, my site is working perfectly fine on PCs and Android phones, but when my friend opened it on his iPhone, about half of screen was covered in black. I checked layers and positions in editor, but nothing seems to be badly positioned, even z-indexes.

I don’t know what can be the problem or how to solve it. On 2 iPhones screen is half-black, not only one.

Here is my site Read-Only: