JSFiddle - React, Tailwind, and code Playground

HTML

<div id="test-div"></div>

CSS

#test-div {
  background-image: moz-linear-gradient(top, #fff 92%, #c2c2c2 92%, #c2c2c2 100%);
  background-size: 1px 8px;    
  width: 500px;
  height: 500px;
}