Default to white background on website

If the user has customized their background color, the text color will
not stay as the default but the background will, leading to unreadable
text.

Closes #4510

www/qute.css

@@ -7,6 +7,7 @@ body {
 	font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
 	-webkit-text-size-adjust: none;
 	color: #333333;
+	background-color: #ffffff;
     overflow-y: scroll;
 }