A working example below with the pepper-grinder color theme. You can choose other themes below or roll your own with Themeroller.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>jQuery UI Accordion</title>
<!--jQuery UI Theme, pepper-grinder-->
<link rel="stylesheet" href="https://code.jquery.com/ui/1.12.1/themes/pepper-grinder/jquery-ui.css">
</head>
<body>
<div id="accordion">
<h3><a href="#">Section 1</a></h3>
<div>
<p>Mauris mauris ante, blandit et, ultrices a, susceros. Nam mi. Proin viverra leo ut odio. Curabitur malesuada. Vestibulum a velit eu ante scelerisque vulputate.</p>
</div>
<h3><a href="#">Section 2</a></h3>
<div>
<p>Sed non urna. Donec et ante. Phasellus eu ligula. Vestibulum sit amet purus. Vivamus hendrerit, dolor at aliquet laoreet, mauris turpis porttitor velit, faucibus interdum tellus libero ac justo. Vivamus non quam. In suscipit faucibus urna. </p>
</div>
<h3><a href="#">Section 3</a></h3>
<div>
<p>Nam enim risus, molestie et, porta ac, aliquam ac, risus. Quisque lobortis. Phasellus pellentesque purus in massa. Aenean in pede. Phasellus ac libero ac tellus pellentesque semper. Sed ac felis. Sed commodo, magna quis lacinia ornare, quam ante aliquam nisi, eu iaculis leo purus venenatis dui. </p>
<ul>
<li>List item</li>
<li>List item</li>
<li>List item</li>
<li>List item</li>
<li>List item</li>
<li>List item</li>
<li>List item</li>
</ul>
</div>
<h3><a href="#">Section 4</a></h3>
<div>
<p>Nam enim risus, molestie et, porta ac, aliquam ac, risus. Quisque lobortis. Phasellus pellentesque purus in massa. Aenean in pede. Phasellus ac libero ac tellus pellentesque semper. Sed ac felis. Sed commodo, magna quis lacinia ornare, quam ante aliquam nisi, eu iaculis leo purus venenatis dui. </p>
</div>
<!--/accordion--></div>
<!--latest jQuery core with integrity check-->
<script src="https://code.jquery.com/jquery-3.2.1.min.js" integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4=" crossorigin="anonymous"></script>
<!--latest jQuery UI with integrity check-->
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js" integrity="sha256-VazP97ZCwtekAsvgPBSUwPFKdrwD3unUfSGVYrahUqU=" crossorigin="anonymous"></script>
<script>
//jQuery UI custom settings
$(function(){
$("#accordion").accordion({
collapsible: true,
active: true,
heightStyle: 'content'
});
});
</script>
</body>
</html>
AdChoices