Header/navbar won't appear/re-appear on mobile - fine on desktop

Design help Animations & Interactions
1

https://preview.webflow.com/preview/t2-digital?utm_medium=preview_link&utm_source=designer&utm_content=t2-digital&preview=41beeea8117190061ef40c3c35719f45&workflow=preview

I am trying to set the navbar (header, really), to move off screen when the user scrolls down (and back on when scrolling up). It works fine on desktop, but it’s not working on tablet and below. Anyone have a suggestion?