JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
        <header id="header">
            header
        </header>

        <section id="headline">
            section
        </section>
        
    </body>
</html>

CSS

html, body {height: 100%;}

#header, #headline { position:absolute; width:100%; top:0; }

#header {height: 100px; z-index:1; background-color:#f40; }
#headline {height: 100%; top:100px; margin-top:-100px; background: #000;}