Menu on iPad (Air) too big in landscape mode

Hello dear community,
I have already found several topics on this issue, but unfortunately I have never found a solution that fixes the problem. On our website , we can’t get the mobile menu to work on an iPad Air in landscape mode. The menu switches to the burger menu, but the header remains as large as on the desktop. The result is very unattractive.

I have already changed the layout for tables in the menu. Are there any other ideas?