<div class="wrap">
  <div class="content">1</div>
  <div class="content">2</div>
  <div class="content">3</div>
</div>
.wrap {
  display:flex;
  flex-flow: column;
  border:2px #ccc solid;
  height:300px;
  margin:0 0 1em;
}
.content {
  padding:1em;
  background-color:#FFCC80;
  margin:0.5em auto;
  width:50%;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.