JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
   <div class="fix"></div>
</div>

CSS

.wrapper {
    max-width: 500px;
    border: 1px solid red;
    height: 5500px;
    position: relative;
    }
    
    
    .fix {
    width: inherit;
    height: 20px;
    position:fixed;
    background: black;
    }