diff --git a/css/css-color/lab-l-over-100-1.html b/css/css-color/lab-l-over-100-1.html
index 287eba98245611..be8833593d7dde 100644
--- a/css/css-color/lab-l-over-100-1.html
+++ b/css/css-color/lab-l-over-100-1.html
@@ -5,13 +5,16 @@
 <link rel="match" href="lab-l-over-100-ref.html">
 <meta name="assert" content="lab() with lightness greater than 100">
 <style>
-    .ref { background-color: lab(100 150 20); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: lab(100 150 20); height: 100px}
     /* l = 150 should clamp back to 100 */
-    .test { background-color: lab(150 150 20); width: 100px; height: 100px}
+    .test { background-color: lab(150 150 20); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/lab-l-over-100-2.html b/css/css-color/lab-l-over-100-2.html
index e85d289d21fa0b..20a95680947532 100644
--- a/css/css-color/lab-l-over-100-2.html
+++ b/css/css-color/lab-l-over-100-2.html
@@ -5,13 +5,16 @@
 <link rel="match" href="lab-l-over-100-ref.html">
 <meta name="assert" content="lab() with lightness greater than 100%">
 <style>
-    .ref { background-color: lab(100% 150 20); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: lab(100% 150 20); height: 100px}
     /* l = 150 should clamp back to 100 */
-    .test { background-color: lab(150% 150 20); width: 100px; height: 100px}
+    .test { background-color: lab(150% 150 20); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/lab-l-over-100-ref.html b/css/css-color/lab-l-over-100-ref.html
index 57328cfa7c5569..eccc492079d2d7 100644
--- a/css/css-color/lab-l-over-100-ref.html
+++ b/css/css-color/lab-l-over-100-ref.html
@@ -2,10 +2,10 @@
 <meta charset="utf-8">
 <title>CSS Color 4: Verify lightness in Lab is always clamped to a value between 0 to 100</title>
 <style>
-    .ref { background-color: lab(100 150 20); width: 100px; height: 200px}
+    .ref { background-color: lab(100 150 20); border: 1px solid black; width: 200px; height: 200px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
+    <p>Test passes if you see a square border with a single color inside.</p>
     <div class="ref"></div>
 </body>
diff --git a/css/css-color/lch-l-over-100-1.html b/css/css-color/lch-l-over-100-1.html
index 6e0c62330c39d3..12d594d1a340f8 100644
--- a/css/css-color/lch-l-over-100-1.html
+++ b/css/css-color/lch-l-over-100-1.html
@@ -5,13 +5,16 @@
 <link rel="match" href="lch-l-over-100-ref.html">
 <meta name="assert" content="lch() with lightness greater than 100">
 <style>
-    .ref { background-color: lch(100 150 20); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: lch(100 150 20); height: 100px}
     /* l = 150 should clamp back to 100 */
-    .test { background-color: lch(150 150 20); width: 100px; height: 100px}
+    .test { background-color: lch(150 150 20); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/lch-l-over-100-2.html b/css/css-color/lch-l-over-100-2.html
index 7752d0dc0eb4d5..68789b9c859f75 100644
--- a/css/css-color/lch-l-over-100-2.html
+++ b/css/css-color/lch-l-over-100-2.html
@@ -5,13 +5,16 @@
 <link rel="match" href="lch-l-over-100-ref.html">
 <meta name="assert" content="lch() with lightness graeter than 100%">
 <style>
-    .ref { background-color: lch(100% 150 20); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: lch(100% 150 20); height: 100px}
     /* l = 150% should clamp back to 100% */
-    .test { background-color: lch(150% 150 20); width: 100px; height: 100px}
+    .test { background-color: lch(150% 150 20); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/lch-l-over-100-ref.html b/css/css-color/lch-l-over-100-ref.html
index 67766274e59ace..291772e166fb93 100644
--- a/css/css-color/lch-l-over-100-ref.html
+++ b/css/css-color/lch-l-over-100-ref.html
@@ -2,11 +2,10 @@
 <meta charset="utf-8">
 <title>CSS Color 4: Specifying LCH with lightness over 100</title>
 <style>
-    .ref { background-color: lch(100 150 20); width: 100px; height: 200px}
+    .ref { background-color: lch(100 150 20); border: 1px solid black; width: 200px; height: 200px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
+    <p>Test passes if you see a square border with a single color inside.</p>
     <div class="ref"></div>
-    <div class="test"></div>
 </body>
diff --git a/css/css-color/oklab-l-over-1-1.html b/css/css-color/oklab-l-over-1-1.html
index 612fe32acb1a83..a16fe7886f83b7 100644
--- a/css/css-color/oklab-l-over-1-1.html
+++ b/css/css-color/oklab-l-over-1-1.html
@@ -5,13 +5,16 @@
 <link rel="match" href="oklab-l-over-1-ref.html">
 <meta name="assert" content="oklab() with lightness greater than 1">
 <style>
-    .ref { background-color: oklab(1 0.5 0.2); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: oklab(1 0.5 0.2); height: 100px}
     /* l = 1.5 should clamp back to 1 */
-    .test { background-color: oklab(1.5 0.5 0.2); width: 100px; height: 100px}
+    .test { background-color: oklab(1.5 0.5 0.2); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/oklab-l-over-1-2.html b/css/css-color/oklab-l-over-1-2.html
index 11948f014bfd27..6300cb8af3bc58 100644
--- a/css/css-color/oklab-l-over-1-2.html
+++ b/css/css-color/oklab-l-over-1-2.html
@@ -5,13 +5,16 @@
 <link rel="match" href="oklab-l-over-1-ref.html">
 <meta name="assert" content="oklab() with lightness greater than 100%">
 <style>
-    .ref { background-color: oklab(100% 0.5 0.2); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: oklab(100% 0.5 0.2); height: 100px}
     /* l = 150 should clamp back to 100 */
-    .test { background-color: oklab(150% 0.5 0.2); width: 100px; height: 100px}
+    .test { background-color: oklab(150% 0.5 0.2); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/oklab-l-over-1-ref.html b/css/css-color/oklab-l-over-1-ref.html
index eb380dcb750e6f..f050bbc6434ee6 100644
--- a/css/css-color/oklab-l-over-1-ref.html
+++ b/css/css-color/oklab-l-over-1-ref.html
@@ -2,10 +2,10 @@
 <meta charset="utf-8">
 <title>CSS Color 4: Verify lightness in Lab is always clamped to a value between 0 to 100</title>
 <style>
-    .ref { background-color: oklab(1 0.5 0.2); width: 100px; height: 200px}
+    .ref { background-color: oklab(1 0.5 0.2); border: 1px solid black; width: 200px; height: 200px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
+    <p>Test passes if you see a square border with a single color inside.</p>
     <div class="ref"></div>
 </body>
diff --git a/css/css-color/oklch-l-over-1-1.html b/css/css-color/oklch-l-over-1-1.html
index 4eb3cda8462639..c734723541d10f 100644
--- a/css/css-color/oklch-l-over-1-1.html
+++ b/css/css-color/oklch-l-over-1-1.html
@@ -5,13 +5,16 @@
 <link rel="match" href="oklch-l-over-1-ref.html">
 <meta name="assert" content="oklch() with lightness greater than 1">
 <style>
-    .ref { background-color: oklch(1 0.5 50); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: oklch(1 0.5 50); height: 100px}
     /* l = 1.5 should clamp back to 1 */
-    .test { background-color: oklch(1.5 0.5 50); width: 100px; height: 100px}
+    .test { background-color: oklch(1.5 0.5 50); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/oklch-l-over-1-2.html b/css/css-color/oklch-l-over-1-2.html
index de8b1a6cdd05c3..59eac2b367764b 100644
--- a/css/css-color/oklch-l-over-1-2.html
+++ b/css/css-color/oklch-l-over-1-2.html
@@ -5,13 +5,16 @@
 <link rel="match" href="oklch-l-over-1-ref.html">
 <meta name="assert" content="oklch() with lightness greater than 100%">
 <style>
-    .ref { background-color: oklch(100% 0.5 50); width: 100px; height: 100px}
+    .square { border: 1px solid black; width: 200px; height: 200px}
+    .ref { background-color: oklch(100% 0.5 50); height: 100px}
     /* l = 150% should clamp back to 100% */
-    .test { background-color: oklch(150% 0.5 50); width: 100px; height: 100px}
+    .test { background-color: oklch(150% 0.5 50); height: 100px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
-    <div class="ref"></div>
-    <div class="test"></div>
+    <p>Test passes if you see a square border with a single color inside.</p>
+    <div class="square">
+        <div class="ref"></div>
+        <div class="test"></div>
+    </div>
 </body>
diff --git a/css/css-color/oklch-l-over-1-ref.html b/css/css-color/oklch-l-over-1-ref.html
index 2c7815c5f0e408..ae1b5e00e57039 100644
--- a/css/css-color/oklch-l-over-1-ref.html
+++ b/css/css-color/oklch-l-over-1-ref.html
@@ -2,10 +2,10 @@
 <meta charset="utf-8">
 <title>CSS Color 4: Verify lightness in Oklch is always clamped to a value between 0 to 1</title>
 <style>
-    .ref { background-color: oklch(1 0.5 50); width: 100px; height: 200px}
+    .ref { background-color: oklch(1 0.5 50); border: 1px solid black; width: 200px; height: 200px}
 </style>
 
 <body>
-    <p>Test passes if you see a single color.</p>
+    <p>Test passes if you see a square border with a single color inside.</p>
     <div class="ref"></div>
 </body>
