Main menu area is changed when 404 error message appears

When I get the error message:
-.............................................
404
OOPS, YOU'VE ENCOUNTERED AN ERROR
It appears the page you were looking for doesn't exist. Sorry about that.
.....................................

I see that my logotype up to the left is shifted upwards. The reason for this is that the main menu height is changed on these occasions.

It is not looking so professional. Can you please direct me to a solution here?

But 404 page shouldn't have any menu visible. Did you modify the original menu/logo layout? If yes, you should add the same styles to offline.css and error.css files.

I just sent you a PM with details on how to see this issue live. Please comment.

Please use PM when we request it. This only takes longer to help you when I need to read several PM messages to see website URL only.