<!DOCTYPE html>
<html>
<head>
<link href="resources/flexbox.css" rel="stylesheet">
 <style>
    .flexbox {
      border: 1px solid black;
      width: 400px;
      height: 200px;
    }
    .item1 {
      margin: 0 auto;
      background: lightblue;
    }
    .item1v {
      margin: auto 0;
      background: lightblue;
    }
    .item2 {
      background: lime;
    }
  </style>
</head>
<body>
  <div class="flexbox column">
    <div class="item1">centeredWithMargins</div>
    <div class="item2 align-self-center">centeredWithAlignSelf</div>
  </div>
  <div style="writing-mode: vertical-lr;">
    <div class="flexbox column">
      <div class="item1v">centeredWithMargins</div>
      <div class="item2 align-self-center">centeredWithAlignSelf</div>
    </div>
  </div>
</body>
</html>