Issue #1860304: Create an outgoing link on missing modules

css/module_filter.css

@@ -30,3 +30,7 @@
 .winnow-clear:hover:after {
   opacity: 1;
 }
+.admin-missing {
+  /* Use Claro variable, but give a default as this will not exist in other themes */
+  color: var(--color-maximumred, #f00);
+}