scope-starting-style.html | Explore in Territory

<!DOCTYPE html>
<title>@scope - inner @starting-style</title>
<link rel="help" href="https://drafts.csswg.org/css-cascade-6/#scope-atrule">
<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/8876">
<link rel="help" href="https://drafts.csswg.org/css-cascade-5/#scope-scope">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  @scope (.a) {
    @starting-style {
      :scope {
        width: 100px;
      }

      .b {
        width: 100px;
      }
    }
  }

  .a, .b {
    transition: width 100s steps(2, start); /* 50% progress */
    width: 200px;
  }
</style>
<main>
  <div class=a>
    <div class=b>
    </div>
  </div>
  <div class=b></div>
</main>
<script>
  test(() => {
    let a = document.querySelector('main > .a');
    let b = document.querySelector('main > .a > .b');
    assert_equals(getComputedStyle(a).width, '150px');
    assert_equals(getComputedStyle(b).width, '150px');

    let out_of_scope_b = document.querySelector('main > .b');
    assert_equals(getComputedStyle(out_of_scope_b).width, '200px');
  }, 'Style rules within @starting-style are scoped');
</script>

chromium/third_party/blink/web_tests/external/wpt/css/css-cascade/scope-starting-style.html