Minor design tweak for smartphones

Author: javiereguiluz

templates/security/login.html.twig

@@ -40,7 +40,7 @@
 
         <div id="login-help" class="col-sm-7">
             <h3>
-                <i class="fa fa-long-arrow-left" aria-hidden="true"></i>
+                <i class="hidden-xs fa fa-long-arrow-left" aria-hidden="true"></i>
                 {{ 'help.login_users'|trans }}
             </h3>