How can I take away the navigation menu for mobile devies?

Site URL: https://heidibrockmyre.com/4-step-reset

I have the navigation removed for the desktop but I don't have it removed for mobile? Can anyone tell me what code I need to inject to do this?

Your code

<style type="text/css">
.Header-inner, 
.Footer,
.tweak-mobile-bar-top-fixed .Mobile-bar--top {
    display: none!important;
}
</style>

change it to

<style>
.Header-inner, .Footer {
    display: none!important;
}
</style>