diff --git a/extensions/simple-browser/media/main.css b/extensions/simple-browser/media/main.css
index 9192d4b6b63..4775dc4a795 100644
--- a/extensions/simple-browser/media/main.css
+++ b/extensions/simple-browser/media/main.css
@@ -93,6 +93,7 @@ iframe {
 	width: 100%;
 	height: 100%;
 	border: none;
+	background: white; /* Browsers default to a white background */
 }
 
 .iframe-focused-alert {