Want to Hide Navigation Bar on only one Page Brine nueva template

Hi There - I've tried the CSS below and it hides the navigation and footers perfectly ... but also everything else! I can't add text or images, etc.

I want to create a blank page with more options and flexibility than a cover page.

I want to have it simply the same as a normal page, (where i can add all the normal text, images, audio, etc) - but removing navigation bar  and footer details. (Changing the page ID of course to the code below. 

--

/* HIDE THE PRIMARY NAVS */
#collection-5d58db8548099500014d80bb .Header-nav--primary {
   display: none!important;
}

/* HIDE THE PRIMARY AND SECONDARY NAVS */
#collection-5d58db8548099500014d80bb .Header-nav {
   display: none!important;
}

Many thanks for any help anyone can give.