JSFiddle - React, Tailwind, and code Playground

HTML

<div class="largeDiv"></div>
<div class="stickyDiv">Test</div>

CSS

.largeDiv {
  height: 1500px;
  width: 100%;
  background: #cccccc;
  
}

.stickyDiv {
  position: sticky;
  bottom: 0px;
  text-align: center;
  background: blue;
  color: white;
  opacity: 0.8;
  padding: 25px;
}

.stickyDiv:hover {
  opacity: 1.0;
}