JSFiddle - React, Tailwind, and code Playground

HTML

<ht></ht>

CSS

ht {
  height:15px;
  width:100%;
  display:block;
  background-image:linear-gradient(to left, rgba(0,0,0,.0) 2%, rgba(0,0,0,1) 50%, rgba(0,0,0,.0) 98%);
}