Storefront Menus Drop Down Behind Main Content

I just updated the Storefront theme and a few settings changed, even though I am using a Child Theme. I think I got all of them fixed except for this one – the one menu option in the header has a drop down with 5 choices. When it drops down, it actually comes in “behind” the main content below it so you can only see the first two choices. The others are covered by the content below the header. I read some other posts that had similar issues but with other themes. I was unable to figure it out.