<!DOCTYPE html>
<html>

<head>
<meta charset="utf-8">
<link rel="author" title="Brandon Stewart" href="mailto:brandonstewart@apple.com">
<link rel="help" href="https://drafts.csswg.org/css-grid-3">
<meta name="assert" content="When the height of an element in the grid changes, ensure the grid is properly resized">
</head>

<style>
  grid {
    display: grid;
    grid-template-rows: masonry;
    grid-template-columns: auto;
    grid-gap: 10px;
    border: 10px;
    border-style: solid;
  }
  item1 {
    background-color: grey;
    height: 125px;
    width: 250px;
  }
  item2 {
    background-color: grey;
    height: 250px;
    width: 250px;
  }
</style>
</head>
<body>
  <grid>
    <item1>1</item1>
    <item2>2</item2>
  </grid>
</body>
</html>