diff --git a/css/css-device-adapt/idlharness.html b/css/css-device-adapt/idlharness.html
deleted file mode 100644
index b9cca1bb7ee2fb..00000000000000
--- a/css/css-device-adapt/idlharness.html
+++ /dev/null
@@ -1,31 +0,0 @@
-<!DOCTYPE html>
-<title>css-device-adapt IDL tests</title>
-<link rel="help" href="https://drafts.csswg.org/css-device-adapt/">
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="/resources/WebIDLParser.js"></script>
-<script src="/resources/idlharness.js"></script>
-
-<style>
-  p { color: black; }
-</style>
-<style>
- @viewport { width: device-width; }
-</style>
-
-<script>
-  'use strict';
-
-  idl_test(
-    ['css-device-adapt'],
-    ['cssom'],
-    idl_array => {
-      idl_array.add_objects({
-        CSSRule: ['cssRule'],
-        CSSViewportRule: ['cssViewportRule'],
-      });
-      self.cssRule = document.styleSheets[0].cssRules[0];
-      self.cssViewportRule = document.styleSheets[1].cssRules[0];
-    }
-  );
-</script>
diff --git a/css/css-values/vh-support-atviewport.html b/css/css-values/vh-support-atviewport.html
deleted file mode 100644
index c1999c4a22e293..00000000000000
--- a/css/css-values/vh-support-atviewport.html
+++ /dev/null
@@ -1,41 +0,0 @@
-<!DOCTYPE html>
-<html><head>
-	<meta charset="utf-8">
-	<title>
-		CSS Values and Units Test:
-		Viewports units are supported in @viewport rules
-	</title>
-	<meta content="
-		Viewports units are supported in @viewport rules
-	" name="assert">
-
-	<link href="mailto:fremycompany.developer@yahoo.fr" rel="author" title="François REMY">
-
-	<link href="http://www.w3.org/TR/css3-values/#viewport-relative-lengths" rel="help">
-	<link href="https://drafts.csswg.org/css-device-adapt-1/#atviewport-rule" rel="help">
-
-	<link href="reference/vh-support-atviewport-ref.htm" rel="match">
-
-	<style type="text/css">
-			html
-				{
-					background-color: yellow;
-				}
-
-			body
-				{
-					background-color: blue;
-					height: 100vh;
-					margin: 0;
-				}
-
-			@viewport
-				{
-					width: 50vw;
-				}
-	</style>
-
-</head>
-<body>
-
-</body></html>
\ No newline at end of file
