<p>foo</p>
<hr/>
<p>bar</p>

hr {
    height: 8px;
    // background-color: red;
    background-image: linear-gradient(90deg, red, transparent);
    
    border: 0;
    height: 1px;
}

body {
    padding: 2em;
    background-color: #ffff00;
}
View Compiled

External CSS

  1. //maxcdn.bootstrapcdn.com/bootswatch/3.3.0/bootstrap.min.css

External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/1.11.1/jquery.min.js
  2. //maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js
  3. //cdnjs.cloudflare.com/ajax/libs/less.js/2.5.1/less.min.js