Add medium-size-desktop class to notification custom title

backend/templates/settings.html

@@ -39,7 +39,7 @@ SMTPS - mailtos://user:pass@mail.domain.com?to=receivingAddress@example.com") }}
                 <div id="notification-customisation" style="display:none;">
 
                     <div class="pure-control-group">
-                        {{ render_field(form.notification_title) }}
+                        {{ render_field(form.notification_title, class="m-d") }}
                         <span class="pure-form-message-inline">Title for all notifications</span>
                     </div>
                     <div class="pure-control-group">