JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>
<body>
  <div id="outerDiv">
      <div id="innerDiv">
      
    </div>
  </div>

</body>
</head>
</html>

CSS

#outerDiv{
  height: 3000px;
  background: grey;
}

#innerDiv{
  height: 30px;
  background: green;
  position: sticky;
  top:0px;
}