Add margin to individual response list

- prevents response title to be mixed up with first question

www/form/app-form.less

@@ -548,6 +548,7 @@
             .cp-form-individual {
                 background: @cp_form-bg1;
                 padding: 10px;
+                margin-bottom: 20px;
                 & > *:not(:last-child) {
                     margin-right: 10px;
                 }