JSFiddle - React, Tailwind, and code Playground

HTML

<header>
    <h>Navigation</h>
    <div>
        <p>Text</p>
    </div>
</header>
<div id="banner"></div>

CSS

body {
    height:3000px;
}
*{
    color:#fff;
}
header {
    position: fixed;
    width: 100%;
    padding:20px;
    background: #373c3f;
}

#banner {
    opacity: 0.3;
    width: 100%;
    height: 150px;
    background: #0ca0b6;
    position: relative;
    z-index: 1;
}