Twenty Seventeen Menu

Hi evrybody,

I expose my problem :
I’m using the”Twenty Seventeen” Theme. I’ve made un top menu (appearing down from index page). This menu contain sub-menu and sub-sub menu. It doese work from evry pages exept from the first : “On mouse over”, the menu goes down, so we can’t see anything…
I’ve teste this on Firefox and IE…

Any solution for me ?

Thank you so much for any arnswer !
Eric

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