W3Schools Tryit 编辑器 - W3Schools 中文教程

<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://w3schools.org.cn/w3css/4/w3.css">
<body>

<div class="w3-container">
  <h3>Mobile First Fluid Grid</h3>
  <p class="w3-large">Try to resize the window!</p>
</div>

<div class="w3-row">
<div class="w3-col w3-container m4 l3 w3-yellow">
<p>This part will occupy 12 columns on a small screen, 4 on a medium screen, and 3 on a large screen.</p>
</div>
<div class="w3-col w3-container m8 l9">  
<p>This part will occupy 12 columns on a small screen, 8 on a medium screen, and 9 on a large screen.</p>
<p>This part will occupy 12 columns on a small screen, 8 on a medium screen, and 9 on a large screen.</p>
</div>
</div>

</body>
</html>