使用 @media 查询来制作响应式设计 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <style>
    body {
      font-family: "Lucida Sans", Verdana, sans-serif;
    }

    .main img {
      width: 100%;
    }

    h1 {
      font-size: 1.625em;
    }

    h2 {
      font-size: 1.375em;
    }

    .header {
      padding: 1.0121457489878542510121457489879%;
      background-color: #f1f1f1;
      border: 1px solid #e9e9e9;
    }

    .menuitem {
      margin: 4.310344827586206896551724137931%;
      margin-left: 0;
      margin-top: 0;
      padding: 4.310344827586206896551724137931%;
      border-bottom: 1px solid #e9e9e9;
      cursor: pointer;
    }

    .main {
      padding: 2.0661157024793388429752066115702%;
    }

    .right {
      padding: 4.310344827586206896551724137931%;
      background-color: #CDF0F6;
    }

    .footer {
      padding: 1.0121457489878542510121457489879%;
      text-align: center;
      background-color: #f1f1f1;
      border: 1px solid #e9e9e9;
      font-size: 0.625em;
    }

    .gridcontainer {
      width: 100%;
    }

    .gridwrapper {
      overflow: hidden;
    }

    .gridbox {
      margin-bottom: 2.0242914979757085020242914979757%;
      margin-right: 2.0242914979757085020242914979757%;
      float: left;
    }

    .gridheader {
      width: 100%;
    }

    .gridmenu {
      width: 23.481781376518218623481781376518%;
    }

    .gridmain {
      width: 48.987854251012145748987854251012%;
    }

    .gridright {
      width: 23.481781376518218623481781376518%;
      margin-right: 0;
    }

    .gridfooter {
      width: 100%;
      margin-bottom: 0;
    }

    @media only screen and (max-width: 500px) {
      .gridmenu {
        width: 100%;
      }

      .menuitem {
        margin: 1.0121457489878542510121457489879%;
        padding: 1.0121457489878542510121457489879%;
      }

      .gridmain {
        width: 100%;
      }

      .main {
        padding: 1.0121457489878542510121457489879%;
      }

      .gridright {
        width: 100%;
      }

      .right {
        padding: 1.0121457489878542510121457489879%;
      }

      .gridbox {
        margin-right: 0;
        float: left;
      }
    }
  </style>
</head>
<body>
  <div class="gridcontainer">
    <div class="gridwrapper">
      <div class="gridbox gridheader">
        <div class="header">
          <h1>The Pulpit Rock</h1>
        </div>
      </div>
      <div class="gridbox gridmenu">
        <div class="menuitem">The Drive</div>
        <div class="menuitem">The Walk</div>
        <div class="menuitem">The Return</div>
        <div class="menuitem">The End</div>
      </div>
      <div class="gridbox gridmain">
        <div class="main">
          <h1>The Walk</h1>
          <p>The walk to the Pulpit Rock will take you approximately two hours, give or take an hour depending on the weather conditions and your physical shape.</p>
          <img src="/examples/pulpitrock.jpg" alt="Pulpit rock" width="" height="">

        </div>
      </div>
      <div class="gridbox gridright">
        <div class="right">
          <h2>What?</h2>
          <p>The Pulpit Rock is a part of a mountain that looks like a pulpit.</p>
          <h2>Where?</h2>
          <p>The Pulpit Rock is in Norway</p>
          <h2>Price?</h2>
          <p>The walk is free!</p>
        </div>
      </div>
      <div class="gridbox gridfooter">
        <div class="footer">
          <p>您可以调整浏览器窗口的大小，来查看不同的内容格式。</p>
        </div>
      </div>
    </div>
  </div>
</body>
</html>
        