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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /css/css-anchor-position/position-anchor-match-parent-rendering.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Anchor Positioning: 'position-anchor: match-parent'</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#valdef-position-anchor-match-parent">
<link rel="author" href="mailto:jeroen.zwartepoorte@gmail.com">
<link rel="match" href="position-anchor-match-parent-rendering-ref.html">
<style>
.cases {
display: flex;
flex-wrap: wrap;
gap: 8px;
width: 642px;
}
.case {
position: relative;
box-sizing: border-box;
width: 122px;
height: 102px;
border: 1px solid silver;
}
.anchor {
position: absolute;
anchor-name: --a;
left: 20px;
top: 20px;
width: 50px;
height: 20px;
background: silver;
}
.parent {
position: fixed;
inset: 0;
}
.probe, .pseudo-parent::before {
position: fixed;
position-anchor: match-parent;
left: anchor(right, 20px);
top: anchor(bottom, 70px);
width: 20px;
height: 20px;
background: green;
}
.pseudo-parent::before {
content: "";
}
</style>
<div class="cases">
<!-- Parent has a default anchor element. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<div class="probe"></div>
</div>
</div>
<!-- Parent has 'position-anchor: none'. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: none">
<div class="probe"></div>
</div>
</div>
<!-- Parent's 'position-anchor' selects no anchor element. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --nonexistent">
<div class="probe"></div>
</div>
</div>
<!-- Parent is not positioned. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position: static; position-anchor: --a">
<div class="probe"></div>
</div>
</div>
<!-- Parent is relatively positioned, so 'position-anchor' does not apply. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position: relative; position-anchor: --a">
<div class="probe"></div>
</div>
</div>
<!-- Parent also uses 'match-parent'. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<div class="parent" style="position-anchor: match-parent">
<div class="probe"></div>
</div>
</div>
</div>
<!-- Chain of 'match-parent' parents, several levels deep. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<div class="parent" style="position-anchor: match-parent">
<div class="parent" style="position-anchor: match-parent">
<div class="parent" style="position-anchor: match-parent">
<div class="probe"></div>
</div>
</div>
</div>
</div>
</div>
<!-- Parent's 'match-parent' resolved to no anchor element. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: none">
<div class="parent" style="position-anchor: match-parent">
<div class="probe"></div>
</div>
</div>
</div>
<!-- Only the grandparent has a default anchor element. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<div class="parent">
<div class="probe"></div>
</div>
</div>
</div>
<!-- Anchored ancestor, with plain wrappers in between. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<div>
<div>
<div class="probe"></div>
</div>
</div>
</div>
</div>
<!-- Intermediate 'match-parent' is not absolutely positioned. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<!-- 'position-anchor' does not apply to the wrapper, so it has no
default anchor element for the probe to match. -->
<div style="position-anchor: match-parent">
<div class="probe"></div>
</div>
</div>
</div>
<!-- Parent's default anchor element is not acceptable for the probe. -->
<div class="case">
<div class="anchor"></div>
<div class="parent" style="position-anchor: --a">
<!-- The containing block of an absolutely positioned probe is the parent
itself, which the anchor element is not a descendant of. -->
<div class="probe" style="position: absolute"></div>
</div>
</div>
<!-- Originating element of a '::before' has a default anchor element. -->
<div class="case">
<div class="anchor"></div>
<div class="parent pseudo-parent" style="position-anchor: --a"></div>
</div>
<!-- Originating element of a '::before' has no default anchor element. -->
<div class="case">
<div class="anchor"></div>
<div class="parent pseudo-parent" style="position-anchor: none"></div>
</div>
</div>