JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block1"></div>
<div class="block2"></div>

CSS

.block1{
  height: 800px;
  width: 600px;
  background-color: yellow;
  z-index: 0;
  position:fixed;
}
.block2{
  z-index: 1;
  height: 2800px;
  width: 800px;
  position: sticky;
  background: #252525;
  right: 50%;
  opacity: .9;
  transform: translate(50%, 10%);
  margin-bottom: 50px;
}