Flexnav menu won't retract on mobile version

[ghost]

Hi,

We have been using the flexnav plugin on our website (http://fortwilderness.com/) for several years and ever since we upgraded to joomla 3, the mobile menu does not retract when on a mobile device. The menu is always fully expanded and blocks the page. You can test it on any mobile device and browser. I think the issue is coming from the javascript but knowing nothing much of javascript I do not know what to look for.

I am not sure what code or screenshot is helpful to show here so please let me know how I can be more specific.

Thanks!