Hide Navigation menu from mobile browser

Using below media query, display none the extra navigation menu you want from the mobile device.

@media only screen
and (min-device-width: 320px)
and (max-device-width: 480px)
and (-webkit-min-device-pixel-ratio: 2) {

}

you can also set the parameter the way you want too. i.e device width and dpi.

Cheers,
Biren

Just be aware that if you edit the theme’s files directly, you’ll lose those changes if the theme is ever updated in the future, to fix bugs or security issues or to add new features. If you use a child theme or a custom CSS plugin or your theme’s built-in custom CSS option, if one exists, your changes will be preserved.