Edit site header on paywall page

Site URL: https://www.softnetwork.art/free-member-home

Hi all, 

Having a similar problem many have had with editing the paywall page. I'd specifically like to remove the header — preferably altogether, but would be happy with just changing the nav item text color to make it not visible. I've had luck editing the body with CSS but not any of the header elements. Any advice? 

You can use this code to Website Tools > Custom CSS

body:has(#sqs-paywall-page-root) header#header {
    display: none !important;
}