Problem with mobile design

Hi everyone!

I started to design the mobile version of the site im working on, but i ran into problems. When i checked the preview, everything seem normal, but when i looked on the site on my phone, i spotted something. There is a huge gap on the top for some reason(you can see it on the picture) and i dont know the reason for it. Could anyone help me with this problem?

Here is my site Read-Only: