Making Custom Sidebar Navigation Responsive

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

Hello,

I am using the following CSS for a custom sidebar navigation menu: 

#headerWrapper header#header {
    height: 100vh !important;
    padding: 15px !important; /* change to anything you want */
}
body.sidebar-position-left #headerWrapper {
    left: 0 !important;
    top: 0 !important;
}

#headerWrapper header#header {
    height: 100vh !important;
}
header#header {
    background: #402533;
}

What do I need to change or add so that the header does not take up 100vh on mobile?

One screenshot shows desktop, which I'm happy with. The other shows mobile, which I need to fix. Thank you!