[help] Menu changes on browser to mobile. I don't want it to.

My site has a simple menu across the top: http://1upfreediving.com/

When I change to mobile it changes to a drop down menu. Though I know when I first made this page a year ago it did not do that. It simply had the menu on the top of the mobile page, which each link below the next instead of next to it.

I didn't change anything so I'm assuming it's in one of the recent updates.

Is it possible to change it back to the old style?