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<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#scroll">
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#fallback-apply">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/test-common.js"></script>
<style>
#cb {
position: relative;
width: 200px;
height: 200px;
border: solid 1px;
}
#scroller {
width: 200px;
height: 200px;
overflow: scroll;
display: flex;
flex-direction: column-reverse;
}
#abspos {
position: absolute;
background: hotpink;
width: 50px;
height: 50px;
position-area: top;
position-try-fallbacks: flip-block;
position-anchor: --a;
}
#anchor {
anchor-name: --a;
width: 50px;
min-height: 50px;
flex: 0;
margin: 150px 0 150px 50px;
background: dodgerblue;
}
</style>
<div id="cb">
<div id="scroller">
<div id="anchor">
</div>
</div>
<div id="abspos"></div>
</div>
<script>
promise_test(async () => {
await waitUntilNextAnimationFrame();
assert_fallback_position(abspos, anchor, 'bottom');
});
promise_test(async () => {
scroller.scrollTop = -100;
await waitUntilNextAnimationFrame();
assert_fallback_position(abspos, anchor, 'top');
});
promise_test(async () => {
scroller.scrollTop = -50;
await waitUntilNextAnimationFrame();
assert_fallback_position(abspos, anchor, 'bottom');
});
</script>
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