Responsive footer menu disappears on narrow screens

First, let me say I appreciate the Catch Box theme and the work and effort that goes into maintaining and enhancing this theme. I am embarrassed to still be using the free theme, but I am scared of breaking my site by changing themes and I'm worried about all the work that might be involved to resolve incompatibilities. The footer menu on http://www.bibletruths.org disappears when the screen is narrowed enough to be responsive. The header menu shrinks to the three bars, but the footer menu disappears completely. I accidentally noticed this on my Samsung Note 4 and verified it with Chrome on my desktop.