CSS - Hide Nav Bar & Footer

Question

I'm looking to hide the navigation bar and footer within a GoNative.io App. I'm not familiar with CSS at all but I have tried this:

nav.navbar.navbar-inverse.navbar-fixed-top {
display: none !important;
}

And several other variations but it just won't hide it.

Here is the layout of the site

I'm a bit confused how the structure needs to be laid out in order for adding custom CSS to hide this.

Answer 1

.navbar{
     visibility: hidden;
}

Answer 2

the selector should be only nav.navbar or just .navbar

nav.navbar{ }