JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div class="fixed"></div>
</div>

CSS

.container{
  background: tomato;
  height: 200px;
  width: 50%;
  transform: translateY(100px);
}

.fixed{
  background: blue;
  position: fixed;
  top: 0;
  right: 0;
  height: 100px;
  width: 100px;
}

*{
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}