JSFiddle - React, Tailwind, and code Playground

HTML

<div>

</div>

CSS

div {
  width: 400px;
  height: 200px;
  border: 1px solid gray;
  
 background: red linear-gradient(to right, transparent 0%, transparent 70%, rgb(0,0,0) 70%,rgb(255,255,255) 100%);
}