Menu's in Graphene theme not working

I am not sure why, but suddenly the menu on the front page of my page, using the Graphene Theme, is now very messed up.

Menu’s now display the beginnings of the page content and the result is the menu is nearly unreadable and near impossible to navigate.

I have deleted and recreated the menu but nothing has changed. I have reinstalled version 3.2.1 of WordPress and still no change.

the website in question is https://www.communicationgallery.net. The menu in question is on the front page.

If anyone can help me out at all as how to repair this problem the help would be massively appreciated.