<!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>Mobile First Responsiveness</h2>
<p class="w3-large">Try to resize the window!</p>
</div>
<div class="w3-row w3-border">
<div class="w3-container w3-half w3-red">
<h2>w3-half</h2>
<p>The w3-half class uses 50% of the parent container.</p>
<p>On screens smaller than 601 pixels it resizes 100%.</p>
</div>
<div class="w3-container w3-half">
<h2>w3-half</h2>
</div>
</div>
</body>
</html>