JSFiddle - React, Tailwind, and code Playground

by napotopia

HTML

<div class="header">Click to expando</div>

CSS

body {
  margin: 10px;
}
.header {
  position:relative;
  padding-left:15px;
}
.header:before, .header.open:before {
  content:'';
  display:inline-block;
  width:0;
  height:0;
  border: 6px solid #444;
  position:absolute;
  left:0;
}
.header:before {
  border-color: transparent transparent transparent #444;
  top:3px;
  left:3px;
}
.header.open:before {
  border-color: #444 transparent transparent transparent;
  top:6px;
}

JavaScript

$('.header').on('click', function () {
  $(this).toggleClass('open');
});