Onepress – Mobile Header blurred

Hi guys,

i have a problem with the header on my page. In the desktop mode on the laptop etc. the header image is fine, but if you open the website via smartphone (or in the customer via mobile button) the header gets blurred. I think it has something to do with the size or sth. but i can not find a solution.

Which size should the header image have to function in every setup (desktop, mobile etc.)? Is there any point in the menu concerning responsive design of the header? I could not find anything.

I would appreciate your help.

Thank you in advance.

Kind regards
Ben

The page I need help with: [log in to see the link]