Menu inconsistencies across PC and Mac

On Chrome on a PC, I get a main menu horizontal spread, which is what I’m hoping for. On Safari and Chrome on a Mac, I get a drop-down main menu. How can I make a consistent menu spread across Mac and PC browsers?

I am using Astrid (v1.18) by aThemes and in the Appearance -> Customize page even on Mac it shows up as a horizontal spread, just not when I actually go to the page. None of the pages have a parent page.

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