diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-001.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-001.html
new file mode 100644
index 00000000000000..63ca0091148f97
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-001.html
@@ -0,0 +1,18 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: unsized div</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-001-ref.html">
+<meta name="assert" content="contain-intrinsic-size is used to size the div as if it had a single child of this size">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+}
+</style>
+
+<div id=target></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-002.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-002.html
new file mode 100644
index 00000000000000..1a2f9941039248
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-002.html
@@ -0,0 +1,24 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: div with max-content parent</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-002-ref.html">
+<meta name="assert" content="contain-intrinsic-size is used to size the div, with parent's max-content width respecting it">
+
+<style>
+#border {
+  width: max-content;
+  border: 1px solid black;
+}
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+}
+</style>
+
+<div id=border>
+  <div id=target></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-003.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-003.html
new file mode 100644
index 00000000000000..51d11b5c599632
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-003.html
@@ -0,0 +1,19 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: width specified</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-003-ref.html">
+<meta name="assert" content="contain-intrinsic-size's width is ignored if width is specified">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+  width: 50px;
+}
+</style>
+
+<div id=target></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-004.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-004.html
new file mode 100644
index 00000000000000..433bcbfb76bfac
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-004.html
@@ -0,0 +1,19 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: width is min-content</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-004-ref.html">
+<meta name="assert" content="div is sized to intrinsic-width if width is min-content">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+  width: min-content;
+}
+</style>
+
+<div id=target></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-005.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-005.html
new file mode 100644
index 00000000000000..d192870c99bab6
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-005.html
@@ -0,0 +1,19 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: width is max-content</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-005-ref.html">
+<meta name="assert" content="div is sized to intrinsic-width if width is max-content">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+  width: max-content;
+}
+</style>
+
+<div id=target></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-006.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-006.html
new file mode 100644
index 00000000000000..6583710b2a37a7
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-006.html
@@ -0,0 +1,18 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: unsized div, intrinsic-size is small</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-006-ref.html">
+<meta name="assert" content="content dimensions are ignored if intrinsic-size is specified">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 5px 6px;
+  contain: size;
+}
+</style>
+
+<div id=target>Lorem ipsum</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-007.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-007.html
new file mode 100644
index 00000000000000..b434c3dfd13f54
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-007.html
@@ -0,0 +1,28 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: div with border</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-007-ref.html">
+<meta name="assert" content="contain-intrinsic-size sizes the content box, not the border box">
+
+<style>
+#border {
+  border: 1px solid blue;
+  width: max-content;
+}
+
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 55px 66px;
+  contain: size;
+  border-style: solid;
+  border-color: black;
+  border-width: 2px 3px 5px 7px;
+}
+</style>
+
+<div id=border>
+  <div id=target></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-008.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-008.html
new file mode 100644
index 00000000000000..927b3933a0579d
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-008.html
@@ -0,0 +1,39 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: writing modes</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-008-ref.html">
+<meta name="assert" content="contain-intrinsic-size specifies physical dimensions, and respects writing modes">
+
+<style>
+.border {
+  border: 1px solid blue;
+  width: max-content;
+  margin: 5px;
+}
+
+.box {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 55px 66px;
+  contain: size;
+  border-style: solid;
+  border-color: black;
+  border-width: 2px 3px 5px 7px;
+  padding: 11px 13px 17px 19px;
+}
+.verticalrl {
+  writing-mode: vertical-rl;
+}
+.verticallr {
+  writing-mode: vertical-lr;
+}
+.horizontaltb {
+  writing-mode: horizontal-tb;
+}
+</style>
+
+<div class=border><div class="box verticalrl">Lorem</div></div>
+<div class=border><div class="box verticallr">Ipsum</div></div>
+<div class=border><div class="box horizontaltb">Dolor</div></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-009.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-009.html
new file mode 100644
index 00000000000000..7c61df35e4f3be
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-009.html
@@ -0,0 +1,69 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS contain-intrinsic-size: select multiple</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<meta name="assert" content="contain-intrinsic-size sizes select multiple">
+
+<style>
+.cis-both {
+  contain-intrinsic-size: 55px 66px;
+}
+
+.cis-width {
+  contain-intrinsic-size: 55px none;
+}
+
+.cis-height {
+  contain-intrinsic-size: none 66px;
+}
+
+select {
+  padding: 0;
+}
+
+.test {
+  display: grid-lanes;
+  contain: size;
+  background: lightblue;
+  border: 1px solid blue;
+  margin: 5px;
+}
+</style>
+
+<!-- To measure the size of an empty <select> without size containment -->
+<select id="reference" multiple size="2"></select>
+
+<select multiple class="test cis-both"
+data-expected-client-width="55" data-expected-client-height="66"></select>
+<select multiple class="test cis-width"
+data-expected-client-width="55"></select>
+<select multiple class="test cis-height"
+data-expected-client-height="66"></select>
+
+<select multiple size="2" class="test cis-width"
+data-expected-client-width="55"></select>
+<select multiple size="2" class="test cis-height"
+data-expected-client-height="66"></select>
+
+<select multiple size="10" class="test cis-width"
+data-expected-client-width="55"></select>
+<select multiple size="10" class="test cis-height"
+data-expected-client-height="66"></select>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/check-layout-th.js"></script>
+<script>
+const reference = document.getElementById("reference");
+const normalWidth = reference.clientWidth;
+for (let test of document.querySelectorAll(".test.cis-width")) {
+  reference.size = test.size || 4;
+  test.dataset.expectedClientHeight = reference.clientHeight;
+}
+for (let test of document.querySelectorAll(".test.cis-height")) {
+  test.dataset.expectedClientWidth = normalWidth;
+ }
+
+checkLayout('.test');
+</script>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-010.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-010.html
new file mode 100644
index 00000000000000..afeac9e8556000
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-010.html
@@ -0,0 +1,17 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: replaced content</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-012-ref.html">
+<meta name="assert" content="contain-intrinsic-size overrides replaced content's intrinsic dimensions">
+
+<style>
+#target {
+  display: grid-lanes;
+  contain-intrinsic-size: 100px 200px;
+  contain: size;
+}
+</style>
+
+<img id=target src="../../../../css-sizing/contain-intrinsic-size/resources/dice.png"></img>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-011.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-011.html
new file mode 100644
index 00000000000000..bbf7adfe3e4a38
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-011.html
@@ -0,0 +1,34 @@
+<!doctype html>
+<html class="reftest-wait">
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: intrinsic-size changes.</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-013-ref.html">
+<meta name="assert" content="changes in intrinsic-size cause reflow">
+<script src="/common/reftest-wait.js"></script>
+
+<style>
+#border {
+  width: max-content;
+  border: 1px solid black;
+}
+#border > div {
+  display: grid-lanes;
+  contain-intrinsic-size: 55px 66px;
+  contain: size;
+}
+</style>
+
+<div id=border><div id=target></div></div>
+
+<script>
+function changeStyle() {
+  document.getElementById("target").style = "contain-intrinsic-size: 77px 88px;";
+  requestAnimationFrame(takeScreenshot);
+}
+
+onload = () => requestAnimationFrame(() => requestAnimationFrame(changeStyle));
+
+</script>
+</html>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-012.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-012.html
new file mode 100644
index 00000000000000..464829fa472bc0
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-012.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: sized div</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-018-ref.html">
+<meta name="assert" content="width / height ignore intrinsic-size">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  width: 55px;
+  height: 66px;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+}
+</style>
+
+<div id=target></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-013.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-013.html
new file mode 100644
index 00000000000000..4bfe85767d3841
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-013.html
@@ -0,0 +1,19 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: div with fit-content width</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../css-sizing/contain-intrinsic-size/contain-intrinsic-size-019-ref.html">
+<meta name="assert" content="div is sized to intrinsic-width when width is fit-content">
+
+<style>
+#target {
+  display: grid-lanes;
+  background: lightblue;
+  contain-intrinsic-size: 111px 222px;
+  contain: size;
+  width: fit-content;
+}
+</style>
+
+<div id=target></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-014-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-014-ref.html
new file mode 100644
index 00000000000000..7ccbd90fc971fe
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-014-ref.html
@@ -0,0 +1,61 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+.grid {
+  display: grid;
+  border: 1px solid black;
+  grid-template-columns: repeat(auto-fit, 100px);
+  height: 40px;
+}
+.one {
+  contain-intrinsic-size: 100px;
+  contain: size;
+  min-width: 200px;
+}
+.two {
+  contain-intrinsic-size: 200px;
+  contain: size;
+  min-width: 100px;
+}
+.three {
+  contain-intrinsic-size: 100px;
+  contain: size;
+  min-width: 200px;
+  max-width: 150px;
+}
+.four {
+  contain-intrinsic-size: 200px;
+  contain: size;
+  min-width: 100px;
+  max-width: 150px;
+}
+.item {
+  background: green;
+  height: 100%;
+}
+</style>
+
+<p>min-width larger than contain-intrinsic-width:
+<div class="grid one">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
+
+<p>min-width smaller than contain-intrinsic-width:
+<div class="grid two">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
+
+<p>max-width ignored since min-width is larger:
+<div class="grid three">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
+
+<p>min-width shrinks grid-lanes container since it overrides contain-intrinsic-width:
+<div class="grid four">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-014.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-014.html
new file mode 100644
index 00000000000000..677d5bf63212e6
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-014.html
@@ -0,0 +1,66 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid auto-fit, min- max- size interactions</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-014-ref.html">
+<meta name="assert" content="auto-fit columns, with intrinsic-size interacting with min- and max- width">
+
+<style>
+.grid-lanes {
+  display: grid-lanes;
+  border: 1px solid black;
+  grid-template-columns: repeat(auto-fit, 100px);
+  height: 40px;
+}
+.one {
+  contain-intrinsic-size: 100px;
+  contain: size;
+  min-width: 200px;
+}
+.two {
+  contain-intrinsic-size: 200px;
+  contain: size;
+  min-width: 100px;
+}
+.three {
+  contain-intrinsic-size: 100px;
+  contain: size;
+  min-width: 200px;
+  max-width: 150px;
+}
+.four {
+  contain-intrinsic-size: 200px;
+  contain: size;
+  min-width: 100px;
+  max-width: 150px;
+}
+.item {
+  background: green;
+  height: 100%;
+}
+</style>
+
+<p>min-width larger than contain-intrinsic-width:
+<div class="grid-lanes one">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
+
+<p>min-width smaller than contain-intrinsic-width:
+<div class="grid-lanes two">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
+
+<p>max-width ignored since min-width is larger:
+<div class="grid-lanes three">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
+
+<p>min-width shrinks grid-lanes container since it overrides contain-intrinsic-width:
+<div class="grid-lanes four">
+  <div class="item">one</div>
+  <div class="item">two</div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-015-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-015-ref.html
new file mode 100644
index 00000000000000..8a2eb6d4b9ee58
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-015-ref.html
@@ -0,0 +1,33 @@
+<!doctype html>
+<meta charset="utf8">
+<style type="text/css">
+.panel {
+  display: grid;
+  background: red;
+  border: 1px solid #ddd;
+  border-radius: 8px;
+  padding: 12px;
+  overflow: visible;
+  position: relative;
+  width: min-content;
+}
+.box {
+  background: green;
+  padding: 8px 10px;
+  border-radius: 6px;
+}
+.panel.size {
+  contain: size;
+}
+.panel.size .box.large {
+  width: 600px;
+}
+</style>
+</head>
+<body>
+<div class="panel size">
+  <div class="box large">
+    The masonry container does not stretch to fit this content.
+  </div>
+</div>
+</body>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-015.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-015.html
new file mode 100644
index 00000000000000..313dab1b45e739
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-015.html
@@ -0,0 +1,39 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: unsized div</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-015-ref.html">
+<meta name="assert" content="size is contained but no inline size is provided">
+<style type="text/css">
+.panel {
+  display: grid-lanes;
+  background: red;
+  border: 1px solid #ddd;
+  border-radius: 8px;
+  padding: 12px;
+  overflow: visible;
+  position: relative;
+  width: min-content;
+}
+.box {
+  background: green;
+  padding: 8px 10px;
+  border-radius: 6px;
+}
+/* Size containment: the panel's used size is independent from its child's size */
+.panel.size {
+  contain: size;
+}
+.panel.size .box.large {
+  width: 600px;
+}
+</style>
+</head>
+<body>
+<div class="panel size">
+  <div class="box large">
+    The masonry container does not stretch to fit this content.
+  </div>
+</div>
+</body>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-001-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-001-ref.html
new file mode 100644
index 00000000000000..91de33c465e31d
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-001-ref.html
@@ -0,0 +1,27 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid;
+  grid-template-columns: 77px 88px;
+  contain-intrinsic-size: 70px 80px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-001.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-001.html
new file mode 100644
index 00000000000000..841d771aea0811
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-001.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid definite size</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-column-001-ref.html">
+<meta name="assert" content="grid container is sized by intrinsic-size, even if definite track sizes overflow">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid-lanes;
+  grid-template-columns: 77px 88px;
+  contain-intrinsic-size: 70px 80px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-002-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-002-ref.html
new file mode 100644
index 00000000000000..94b80e01b15c79
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-002-ref.html
@@ -0,0 +1,26 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid;
+  grid-template-columns: 3fr 4fr;
+  contain-intrinsic-size: 70px 80px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-002.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-002.html
new file mode 100644
index 00000000000000..76ef1b2b9148fc
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-002.html
@@ -0,0 +1,31 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid indefinite size</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-column-002-ref.html">
+<meta name="assert" content="grid container is sized by intrinsic-size, with fr-tracks using that space">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid-lanes;
+  grid-template-columns: 3fr 4fr;
+  contain-intrinsic-size: 70px 80px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-003-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-003-ref.html
new file mode 100644
index 00000000000000..1df51c5d1e2e28
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-003-ref.html
@@ -0,0 +1,27 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid;
+  grid-template-columns: 77px 88px;
+  contain-intrinsic-size: 200px 300px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-003.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-003.html
new file mode 100644
index 00000000000000..08664fbd0e3c7c
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-column-003.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid definite size, large size</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-column-003-ref.html">
+<meta name="assert" content="contain-intrinsic-size sizes grid container, even if definite tracks are smaller">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid-lanes;
+  grid-template-columns: 77px 88px;
+  contain-intrinsic-size: 200px 300px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-logical-001.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-logical-001.html
new file mode 100644
index 00000000000000..3971a0dd3fc5a2
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-logical-001.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: Logical versions</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="../../../../reference/ref-filled-green-100px-square-only.html">
+
+<p>Test passes if there is a filled green square.</p>
+
+<div style="display: grid-lanes; contain: size; contain-intrinsic-inline-size: 50px; contain-intrinsic-block-size: 100px; background: green; writing-mode: vertical-lr;"></div>
+<div style="width: 100px; height: 50px; background: green;"></div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-001-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-001-ref.html
new file mode 100644
index 00000000000000..de20135ce128c4
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-001-ref.html
@@ -0,0 +1,27 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid;
+  grid-template: 55px 66px;
+  contain-intrinsic-size: 70px 80px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-001.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-001.html
new file mode 100644
index 00000000000000..72dd85ffc81194
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-001.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid definite size</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-row-001-ref.html">
+<meta name="assert" content="grid container is sized by intrinsic-size, even if definite track sizes overflow">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid-lanes;
+  grid-template-rows: 55px 66px;
+  contain-intrinsic-size: 70px 80px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-002-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-002-ref.html
new file mode 100644
index 00000000000000..df1f5e7da021d0
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-002-ref.html
@@ -0,0 +1,26 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid-lanes;
+  grid-template-rows: 1fr 2fr;
+  contain-intrinsic-size: 80px 90px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-002.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-002.html
new file mode 100644
index 00000000000000..bb802eb853f7c0
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-002.html
@@ -0,0 +1,31 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid indefinite size</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-row-002-ref.html">
+<meta name="assert" content="grid container is sized by intrinsic-size, with fr-tracks using that space">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid;
+  grid-template-rows: 1fr 2fr;
+  contain-intrinsic-size: 80px 90px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-003-ref.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-003-ref.html
new file mode 100644
index 00000000000000..0310deb505caf7
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-003-ref.html
@@ -0,0 +1,27 @@
+<!doctype html>
+<meta charset="utf8">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid;
+  grid-template-rows: 55px 66px;
+  contain-intrinsic-size: 200px 300px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
diff --git a/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-003.html b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-003.html
new file mode 100644
index 00000000000000..a9538fe3cb0382
--- /dev/null
+++ b/css/css-grid/grid-lanes/tentative/intrinsic-sizing/grid-lanes-contain-intrinsic-size-row-003.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset="utf8">
+<title>CSS contain-intrinsic-size: grid definite size, large size</title>
+<link rel="author" title="Celeste Pan" href="mailto:celestepan@microsoft.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-3">
+<link rel="match" href="grid-lanes-contain-intrinsic-size-row-003-ref.html">
+<meta name="assert" content="contain-intrinsic-size sizes grid container, even if definite tracks are smaller">
+
+<style>
+#grid {
+  border: 3px solid black;
+  display: grid-lanes;
+  grid-template-rows: 55px 66px;
+  contain-intrinsic-size: 200px 300px;
+  contain: size;
+  width: max-content;
+  background: lightblue;
+  grid-gap: 5px;
+}
+.item {
+  background: lightgreen;
+  opacity: 0.5;
+  height: 100%;
+}
+</style>
+
+<div id=grid>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+  <div class=item></div>
+</div>
