Mobile menu issues

Hello, I’ve added this code to display the main nav on mobile sizes, but the hamburger menu is still appearing:

@media handheld,only screen and (max-width:900px){
#show-nav-menu{display:none !important}
#main-nav { display: inline-block !important; }
}

Also, I need the nav font size to scale down on phones but can’t seem to get that work. Site is https://new.npolicy.org/

Thank you!