<!DOCTYPE html>
<title>CSS Anchor Positioning: anchor-scope and Shadow DOM</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#anchor-scope">
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/10325">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id=host>
<template shadowrootmode=open>
<style>
::slotted(.outer_anchored), .inner_anchored {
background: coral;
position: absolute;
top: anchor(bottom, 1px);
position-anchor: --a;
width: 5px;
height: 5px;
}
.anchor {
background: skyblue;
height: 10px;
anchor-name: --a;
}
.cb {
position: relative;
width: 200px;
height: 200px;
border: 1px solid black;
}
.scope {
anchor-scope: --a;
}
</style>
<div class=cb>
<div class=anchor></div>
<div class=scope>
<div class=anchor></div>
<slot></slot><!-- .outer_anchored appears here in the flat tree-->
</div>
<div class=inner_anchored></div>
</div>
</template>
<div class=outer_anchored></div>
</div>
<script>
test((t) => {
// The outer_anchored element is slotted into the <slot> in
// the shadow tree. It should be in the same anchor-scope
// as the second .anchor element.
let outer_anchored = document.querySelector('.outer_anchored');
assert_equals(getComputedStyle(outer_anchored).top, '20px');
// The inner_anchored element exists directly in the shadow tree,
// and can not see the second .anchor since it's hidden behind
// an anchor-scope.
let inner_anchored = host.shadowRoot.querySelector('.inner_anchored');
assert_equals(getComputedStyle(inner_anchored).top, '10px');
}, 'anchor-scope scopes to the flat tree');
</script>
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