w3-panel : The w3-panel class is used to add 16px left and right padding along with 16px top and bottom margin also to HTML elements.
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
</head>
<body>
<div class="w3-panel w3-aqua">
<h1> GHI</h1>
<p> I am Panel 1 </p>
</div>
<div class="w3-panel w3-teal">
<h1> JKL</h1>
<p> I am Panel 2 </p>
</div>
</body>
</html>