Setting the .mobile-nav-container to position: fixed and height to 100% will fill screen as desired, but you will need to consider your layout in terms of user scroll when the nav is open on mobile.
- If you want to continue to use the trigger effect and have it visible when the menu is open the nav will ideally be fixed to the top (as to avoid scroll issues when open).
- Alternatively, the .mobile-nav-container will sit above the nav and have a separate close trigger (so it functions as a slide-in, slide-out nav).
Both options will work fine - designers choice! Hope this helps. 