<!DOCTYPE html>
<html>
<head>
    <title>CSS Flexible Box Test: flex-direction proprety - column</title>
    <link rel="author" title="haosdent" href="mailto:haosdent@gmail.com">
    <style type="text/css">
        /* Positioned container allows for the self-describing statement to still
           be visible in the case of failure */
        .container {
            position: relative;
            background: red;
            margin: 1em 0;
            border: 1px solid black;
        }
        span ~ span {
            margin: 2em 1em 1em;
        }
        span {
            display: block;
            background: green;
            color: white;
            margin: 1em;
            width: 8em;
        }
    </style>
</head>
<body>
    <p>The test passed if you see all the cells are arraged vertically.</p>
    <div class="container">
      <span>first</span>
      <span>second</span>
      <span>third</span>
      <span>forth</span>
    </div>
</body>
</html>