Full Bleed (underneath header) on ALL pages

https://flute-alligator-dfrx.squarespace.com/

password: floral

Hi! I am wanting a full bleed into the header on all pages (aka all blocks go underneath the header). I have done this successfully on the homepage using the code below, however when I try to use this code for other pages by replacing the body.homepage with the page IDs (aka collection-) it does not work on the other pages. Suggestions? Thanks! 

body.homepage header#header {
    position: absolute !important;
    background: transparent !important;
}
body.homepage .header-announcement-bar-wrapper {
    background: transparent !important;
    position: absolute !important;
}

Thanks Ziggy ❤️ You da' best