Mark the active Text or Image tab.

The active tab stays solid green, and the other tab is pale with green
text. A tab whose field failed validation now shows red text.

publish/style.css

@@ -118,11 +118,27 @@ div.note {
   padding-top: 3px;
   padding-bottom: 3px;
   padding-left: 5px;
-  background-color: #006633;
-  color: white;
+  background-color: #e3ebe6;
+  color: #006633;
   cursor: pointer;
   border-radius: 8px 0 0 8px;
 }
+#main .tab:hover {
+  background-color: #d2e2d8;
+}
+/* The tab that is showing */
+#main .tab.active {
+  background-color: #006633;
+  color: white;
+  cursor: default;
+}
+/* A tab whose field failed validation */
+#main .tab.red {
+  color: #cc0000;
+}
+#main .tab.active.red {
+  color: #ffd0d0;
+}
 /* WordCount */
 #main .counter {
   font-size: 11pt;