adapt.css: make diff colors red/green

adapt.css

@@ -160,6 +160,14 @@ h2.wikiaction { margin:0px }
   padding:2px;
 }
 
+/* Diff View */
+.diffmarkup del {
+  background-color: #fdd !important;
+}
+.diffmarkup ins {
+  background-color: #dfd !important;
+}
+
 /* For the (Site.)Search page */
 .searchbox {
   margin-right:2px;