diff --git a/tests/wpt/mozilla/tests/css/input_button_margins_a.html b/tests/wpt/mozilla/tests/css/input_button_margins_a.html
index 37766fe87e5..9f8f6558343 100644
--- a/tests/wpt/mozilla/tests/css/input_button_margins_a.html
+++ b/tests/wpt/mozilla/tests/css/input_button_margins_a.html
@@ -7,6 +7,8 @@ body, html {
 input {
     margin-left: 64px;
     border: none;
+    background: lightblue;
+    color: transparent;
     vertical-align: top;
 }
 </style>
diff --git a/tests/wpt/mozilla/tests/css/input_button_margins_ref.html b/tests/wpt/mozilla/tests/css/input_button_margins_ref.html
index 63b80497bf4..b2822ec7e33 100644
--- a/tests/wpt/mozilla/tests/css/input_button_margins_ref.html
+++ b/tests/wpt/mozilla/tests/css/input_button_margins_ref.html
@@ -7,6 +7,8 @@ input {
     position: absolute;
     left: 64px;
     border: none;
+    background: lightblue;
+    color: transparent;
 }
 </style>
 <input type=button value=Hello>