JSFiddle - React, Tailwind, and code Playground

HTML

<div class="element"></div>

CSS

.element{
  opacity: 1;
  background: red;
  width: 100px;
  height: 100px;
  animation-name: a1;
  animation-duration: 1s;
  animation-delay:10s;
  animation-fill-mode: forwards;
}

@keyframes a1{
  from {opacity: 1;}
  to {opacity: 0;}	
}