Page tabs on Home page don't render in IE or Safari; using "Green Tea" theme

My tabs for top level pages don’t render correctly in IE or Safari. Looks GREAT in Chrome! I’m using the free “green tea” theme. I am total newbie to WordPress. This is a free site for a church.

https://www.wcclv.org

Also, while we’re at it, I just supposed that adding pages under a “parent” page would give me a drop down on that main menu (where the tabs aren’t rendering correctly). I guess I’m gonna have to do some coding to make that happen??

Thanks!