Disable Page Scrolling with Full Screen Menu

Hello! I have searched this forum and found threads with solutions to similar issues, but none of which I can get my full screen navigation to stop the page from scrolling.

My nav is custom built so there is no navbar element. It’s a Div block trigger.

Here’s my share link.

Any help would be greatly appreciated!

Bump up. Anyone have any suggestions on how to get this to work? I am nearing the completion of my website design and this is one of the last things I want to fix. Thank you in advance!