1 files changed, 42 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/semantics/interactive-elements/the-dialog-element/modal-dialog-backdrop-ref.html b/testing/web-platform/tests/html/semantics/interactive-elements/the-dialog-element/modal-dialog-backdrop-ref.html
new file mode 100644
index 0000000000..d703b7f28e
--- /dev/null
+++ b/testing/web-platform/tests/html/semantics/interactive-elements/the-dialog-element/modal-dialog-backdrop-ref.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<style>
+.dialog-default-ua-style {
+    position: absolute;
+    overflow: auto;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    left: 0;
+    margin: auto;
+    border: solid;
+    padding: 1em;
+    background: white;
+    color: black;
+}
+
+#dialog {
+    margin: auto;
+    height: 100px;
+    width: 100px;
+    top: 100px;
+    z-index: 1000;
+    background: green;
+}
+
+#backdrop {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    background: rgba(0,0,0,0.1);
+    z-index: 100;
+}
+</style>
+<body>
+Test for the default user agent style of dialog::backdrop. The test passes if
+there is a green box, above a very lightly translucent gray box spanning the
+viewport.
+<div id="backdrop"></div>
+<div class="dialog-default-ua-style" id="dialog"></div>
+</body>