<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-backgrounds-3/#background-color">
<link rel="match" href="simple-bg-color-ref.html">
<style>
.box1 {
  width: 100px;
  height: 150px;
  background-color: green;
}
.box2 {
  width: 200px;
  height: 250px;
  background-color: red;
}
</style>
<body>
  <div class='box1'></div>
  <div class='box2'></div>
</body>