@Paulie_D – I’m not sure how to edit my original post, but here’s the codepen which should make things much easier to look at.
Right now the overlay is commented out in the html. If you uncomment it, you’ll see that it covers the hamburger menu icon on the far right. I know there’s a way to keep the icon in its parent container and still have a z-index higher than the overlay. There is a Jsfiddle on it being done, but it’s not quite working in my situation.