JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container"></span><span class="arrow-right"></span></div>

CSS

.container {
  width: 60%;
  height: 9px;
  background: #ccc;
  margin: 100px auto;
    -moz-border-radius: 50px 0 0 50px;
    border-radius: 50px 0 0 50px;
}
.arrow-right {
  width: 0;
  height: 0;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 27px solid #ccc;
  float: right;
  margin-top: -7px;
  margin-right: -26px;
}