css/selectors/nesting-ref.html

<!DOCTYPE html>
<title>@nest | basic</title>
<link rel="author" title="Adam Argyle" href="mailto:argyle@google.com">
<link rel="help" href="https://drafts.csswg.org/css-nesting-1/">
<style>
  .test {
    background-color: red;
    width: 100px;
    height: 100px;
    display: grid;
  }

  .test-1 > div {
    background-color: green;
  }

  .test-2 > div {
    background-color: green;
  }

  .test-3 .test-3-child {
    background-color: green;
  }

  .test-4 section > span > b {
    display: inline-block;
    background-color: green;
    width: 100%;
    height: 100%;
  }

  @media (min-width: 50px) {
    .test-5 > div {
      background-color: green;
    }
  }

  .test-6.test {
    background-color: green;
  }

  :is(.test-7, .t7-) + .test-7-child,
  :is(.test-7, .t7-).t7-- {
    background-color: green;
  }

  .test-8 {
    background-color: green;
  }

  .test-9:is(.t9-, .test-9.t9--) {
    background-color: green;
  }

  @supports (display: grid) {
    .test-10 {
      background-color: green;
    }
  }

  body * + * {
    margin-top: 8px;
  }
</style>
<body>
  <p>Tests pass if <strong>block is green</strong></p>
  <div class="test test-1"><div></div></div>
  <div class="test test-2"><div></div></div>
  <div class="test test-3"><div class="test-3-child"></div></div>
  <div class="test test-4">
    <section>
      <span><b></b></span>
    </section>
  </div>
  <div class="test test-5"><div></div></div>
  <div class="test test-6"><div></div></div>
  <div class="test t7- t7--"><div class="test-7-child"></div></div>
  <div class="test test-8"><div></div></div>
  <div class="test test-9 t9-- t9-"><div></div></div>
  <div class="test test-10"><div></div></div>
</body>