Menu slides offscreen–any fix?

I just started working on the webpage for the volunteer fire department my husband and sons are in, so bear with me as I didn’t set *everything* up myself. I have done a pretty well full overhaul though, including updating wordpress to the most recent, applying a new theme, adding the jetpack plugin and rearranging menu items.

The problem I am running into is the primary menu–which is on top–is sliding off screen and I can’t seem to find a fix whether in the theme itself or the CSS. Please take a look and see if you can figure out where the problem is? If it’s just the theme I can use a different one obviously, I’d just hate to waste all the time I already spent if there is another solution. For what it’s worth, I can put the menu on the left as well, but that completely screws up on mobile and I still can’t remove the top menu.

Here is the site:

http://www.mrwfire.org/

Thank you!