<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="4/w3.css">
<body>
<div class="w3-container">
<h2>Accordions</h2>
<p>An accordion with links:</p>
<button onclick="myFunction('Demo1')" class="w3-button w3-block w3-black w3-left-align">
Accordion 1</button>
<div id="Demo1" class="w3-hide">
<a class="w3-button w3-block w3-left-align" href="#">Link 1</a>
<a class="w3-button w3-block w3-left-align" href="#">Link 2</a>
<a class="w3-button w3-block w3-left-align" href="#">Link 3</a>
</div>
</div>
<script>
function myFunction(id) {
var x = document.getElementById(id);
if (x.className.indexOf("w3-show") == -1) {
x.className += " w3-show";
} else {
x.className = x.className.replace(" w3-show", "");
}
}
</script>
</body>
</html>