<!DOCTYPE html>
<html>
  <meta charset="utf-8">
  <title>CSS Multi-column Layout Test: Test the column-rule's block-size</title>
  <link rel="author" title="Ting-Yu Lin" href="tlin@mozilla.com">
  <link rel="author" title="Mozilla" href="https://www.mozilla.org/">

  <style>
  article {
    column-count: 2;
    column-rule: 6px solid;
    width: 400px;
    height: 500px;
    background-color: lightgreen;
    border: 2em solid purple;
    padding: 2em;
  }
  div.block {
    width: 100px;
    height: 200px;
  }
  div.column-span {
    column-span: all;
    height: 50px;
    background-color: lightblue;
  }
  </style>

  <article>
    <div class="block">block1</div>
    <div class="column-span">column-span1</div>
    <div class="block">block2</div>
    <div class="column-span">column-span2</div>
    <div class="block" style="height: 400px;">block3</div>
  </article>
</html>