JSFiddle - React, Tailwind, and code Playground

HTML

<div class="btn"></div>

CSS

.btn {
  background: red;
  box-shadow: inset 5px 5px 10px rgba(255,255,255,.5), inset -5px -5px 10px rgba(0,0,0,.5);
  border-radius: 10px;
  width: 500px;
  height: 50px;
}