Hide Menus on Protected Pages

Hi,
I am just getting started with Grav and I am trying to password protect my whole site. I have been playing around with the private plugin (preferred, don't need different users) as well as the admin plugin. Pages are protected as expected, but the header and menu structure are still visible - this was the same for the antimatter and the learn2 theme. Is there an easy way to hide menus and/or just display the login window?
Thanks so much!

Is there a reason you don't just use basic auth? If you don't need interactive registration and such, and you just want to wall off the entire site, it's the simplest and most standards compliant way to do it.

Easiest thing is to edit the theme's base twig and wrap the menu in a {% if grav.user.username %} check.