add cd-add button to vm config

Signed-off-by: Arthur Lu <learthurgo@gmail.com>

css/style.css

@@ -87,6 +87,10 @@ img.clickable {
 	visibility: hidden;	
 }
 
+.none {
+	display: none;
+}
+
 .visuallyhidden {
 	border: 0;
 	clip: rect(0 0 0 0);