diff --git a/css/css-pseudo/highlight-cascade-008-ref.html b/css/css-pseudo/highlight-cascade-008-ref.html
new file mode 100644
index 000000000000000..a982ab30ecd7146
--- /dev/null
+++ b/css/css-pseudo/highlight-cascade-008-ref.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<title>Custom property values from the root element</title>
+<script src="support/selections.js"></script>
+<style>
+  div::selection {
+    background-color: green;
+    text-decoration-line: underline;
+    text-decoration-style: line;
+    text-decoration-thickness: 1px;
+    text-decoration-color: blue;
+  }
+</style>
+<div>PASS if background-color is green when selected, underline is 1px thick and blue.</div>
+<script>
+  selectNodeContents(document.querySelector("div"));
+</script>
\ No newline at end of file
diff --git a/css/css-pseudo/highlight-cascade-008.html b/css/css-pseudo/highlight-cascade-008.html
new file mode 100644
index 000000000000000..0bc1369ba1db4aa
--- /dev/null
+++ b/css/css-pseudo/highlight-cascade-008.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<title>Custom property values from the root element</title>
+<link rel="author" title="Stephen Chenney" href="mailto:schenney@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#highlight-cascade">
+<link rel="match" href="highlight-cascade-008-ref.html">
+<meta name="assert" value="This test verifies that when a custom property is not found in highlight cascade, it's value is taken from the root element.">
+<script src="support/selections.js"></script>
+<style>
+  :root {
+    --background-color: green;
+    --decoration-thickness: 10px;
+    --decoration-color: purple;
+  }
+  ::selection {
+    --decoration-thickness: 1px;
+    --decoration-color: green;
+  }
+  div::selection {
+    --decoration-color: blue;
+    background-color: var(--background-color, red);
+    text-decoration-line: underline;
+    text-decoration-style: line;
+    text-decoration-thickness: var(--decoration-thickness, 5px);
+    text-decoration-color: var(--decoration-color, red);
+  }
+</style>
+<div>PASS if background-color is green when selected, underline is 1px thick and blue.</div>
+<script>
+  selectNodeContents(document.querySelector("div"));
+</script>
\ No newline at end of file
