JSFiddle - React, Tailwind, and code Playground

HTML

<div class="relative"><div class="absolute"><div class="fixed"></div></div></div>

CSS

.relative {
   position: relative;
   background-color: red;
   left: 100px;
   height: 500px;
   width: 500px;
}

.absolute {
  position: absolute;
  left: 0;
  right: 0;
  background-color: grey;
}

.fixed {
  position: fixed;
  border: 2px solid blue;
  width: 200px;
  height: 200px;
  top: 100px;
}