Mobile Menu - Can I make it expandable at launch, for user to choose NAV item, and then proceed to that page?

Site URL: https://www.trishthomasmeyer.com/

Once I enter my site, I want to see this view (menu expanded) - is this possible?

It looks like you figured it out with this CSS?

@media only screen and (max-width: 800px) {
    div#mobileNav {
        height:auto !important;
    }
}