<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Flexbox Test: gap - rows and columns</title>
<link rel="author" title="Adam Argyle" href="mailto:argyle@google.com">
<style>
  section {
    background-color: green;
    block-size: 100px;
    display: flex;
    flex-wrap: wrap;
  }
  section > div{
    background-color: grey;
    width: calc(50% - 10px);
  }
  section > div:nth-child(1),
  section > div:nth-child(3) {
    margin-inline-end: 20px;
  }
  section > div:nth-child(3),
  section > div:nth-child(4) {
    margin-block-start: 20px;
  }
</style>
<body>
  <p>Test passes if there are <strong> green lines between boxes</strong>.</p>
  <section>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
  </section>
</body>