<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<body>
<div class="w3-container">
<h2>Responsive Layout</h2>
<p>The w3-mobile class displays HTML elements vertically on small screens and horizontally on medium/large screens. Resize the browser window to see the effect.</p>
</div>
<div class="w3-cell-row">
<div class="w3-container w3-red w3-cell w3-mobile">
<p>Hello W3.CSS Layout.</p>
</div>
<div class="w3-container w3-green w3-cell w3-mobile">
<p>Hello W3.CSS Layout.</p>
</div>
<div class="w3-container w3-blue w3-cell w3-mobile">
<p>Hello W3.CSS Layout. Hello W3.CSS Layout.</p>
</div>
</div>
</body>
</html>