add styles for valid and invalid form controls

Author: valburyakov

src/styles.css

@@ -15,4 +15,12 @@ body {
 
 .comma-list:last-child::after {
   content: "";
-}
+}
+
+.ng-valid[required], .ng-valid.required  {
+  border-left: 5px solid #42A948; /* green */
+}
+
+.ng-invalid.ng-touched:not(form)  {
+  border-left: 5px solid #a94442; /* red */
+}