Stop primary navigation dropping under search bar

Hi all, my site is betterrelationships.com.au – I’m working with a child theme of twenty fourteen.

My primary navigation menu aligns fine with the search toggle on most screen sizes. However when I resize the screen to less than 985px the nav menu drops to a row below the header-main div. I’m trying to figure out how to keep it on the same level.

Since the menu is so wide it will have to go to two lines – that’s fine, I just want the top line to stay on the header-main div level alongside the search toggle. Particularly since the way it is now, if you activate the search toggle the search bar covers up the nav menu!

Would be very grateful for any help. I’ve been playing with the styles for hours and just can’t figure it out >_<