Additional CSS and Customization Not Working Navigation iPhone

Hello,

I've tried additional CSS and customization and nothing is taking effect when it comes to font sizing and spacing the main and off panel navigation menu on my iPhone and iPad mobile devices, it does however, work on my iMac.

Here's my site:
https://wordpress-805049-2758224.cloudwaysapps.com/

And here's the code that's not taking effect...PLEASE HELP!:

.mobile-menu-control-wrapper .menu-toggle, .mobile-menu-control-wrapper .menu-toggle:hover, .mobile-menu-control-wrapper .menu-toggle:focus, .has-inline-mobile-toggle #site-navigation.toggled {
background-color: #32373c;
}

.gp-icon svg {
height: 1em;
width: 1em;
top: 0.125em;
position: relative;
fill: #fff;
}
.main-navigation a, .main-navigation .menu-toggle, .main-navigation .menu-bar-items {
font-weight: 600;
text-transform: uppercase;
font-size: 20px;
}