w3css 在线编辑器 | w3css代码测试

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

<div class="w3-container">
<h2>移动优先响应</h2>
<h3>嵌套行（w3-half 内有 w3-half）</h3>
<p class="w3-large">尝试调整窗口大小！</p>
</div>

<div class="w3-row">
  <div class="w3-half w3-container w3-green">
    <h2>w3-half</h2>
    <div class="w3-row">
      <div class="w3-half w3-container w3-red">
        <h2>w3-half</h2>  
        <p>这是一个段落。</p>
      </div>
      <div class="w3-half w3-container w3-yellow">
        <h2>w3-half</h2>  
        <p>这是一个段落。</p>
      </div>
    </div>
  </div>
  <div class="w3-half w3-container w3-blue">
    <h2>w3-half</h2>
    <div class="w3-row">
      <div class="w3-half w3-container w3-red">
        <h2>w3-half</h2>  
        <p>这是一个段落。</p>
      </div>
      <div class="w3-half w3-container w3-yellow">
        <h2>w3-half</h2>  
        <p>这是一个段落。</p>
      </div>
    </div>
  </div>
</div>

</body>
</html>

报个问题: