JSFiddle - React, Tailwind, and code Playground

HTML

<div class="fixedContainer">
    This is experimental
</div>
<div class="otherContainer"></div>

CSS

.fixedContainer {
    background-color:#ddd;
    position: fixed;
    padding: 2em;
    left: 50%;
    top: 0%;
    transform: translateX(-50%);
}

.otherContainer {
    height:1000px;
    background-color:#bbb;
}