<!DOCTYPE html>
<title>Tests that the anchor element can be in a different tree scope</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#target-anchor-element">
<link rel="author" href="mailto:xiaochengh@chromium.org">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
.cb {
  position: absolute;
}

#host1::part(anchor) {
  anchor-name: --a1;
  margin-left: 15px;
}
#target1 {
  position: absolute;
  left: anchor(--a1 left);
}
</style>

<div class="cb">
  <div id="host1"></div>
  <div id="target1"></div>
</div>

<div class="cb">
  <div id="host2"></div>
</div>

<script>
test(() => {
  host1.attachShadow({mode: 'open'}).innerHTML = '<div part="anchor"></div>';
  assert_equals(target1.offsetLeft, 15);
}, 'Should be able to set anchor-name to a shadow DOM part and anchor to it');

test(() => {
  let shadow = host2.attachShadow({mode: 'open'});
  shadow.innerHTML = `
    <style>
      :host {
        anchor-name: --a2;
        margin-left: 15px;
      }
      #target2 {
        position: absolute;
        left: anchor(--a2 left);
      }
    </style>
    <div id="target2"></div>
  `;
  assert_equals(shadow.getElementById('target2').offsetLeft, 15);
}, 'Should be able to set anchor-name to the shadow host and anchor to it');
</script>
