d: lightgreen;
      }
      div.b {
        width: 20px;
        height: 50px;
        background: pink;
      }
      div.c {
        width: 20px;
        height: 100px;
        background: orange;
      }
    </style>
  </head>
  <body>

    <!-- default (start) -->
    <div class="flexbox">
      <div class="a" style="margin-top:190px"/>
    </div>
    <div class="flexbox">
      <div class="b" style="margin-top:140px"/><div class="a"></div>
    </div>
    <div class="flexbox">
      <div class="c" styl