Responsive visibility in desktop mode?

Loving UpFront so far, but the responsive features are giving me a little trouble.

Is there a way to have an element visible below the mobile breakpoint, but NOT past desktop width? I'd like to make a custom sticky menu with a code block that only appears in the mobile version, but the built in handles only allow me to toggle visibility for the mobile and tablet breakpoints. I could set my own breakpoints with CSS, but that seems redundant when it's a theme feature.

Thanks!