<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div class="button-down"></div>

.button-down { position: relative; } .button-down::after { content: ""; position: absolute; left: 17px; z-index: 11; display: block; width: 25px; height: 25px; border-top: 2px solid #f33; border-left: 2px solid #f33; transform: rotate(225deg); }