diff --git a/template/link.php b/template/link.php
index c37b870..b3652a3 100644
--- a/template/link.php
+++ b/template/link.php
@@ -1,34 +1,36 @@
 <?php
 # Copyright (C) 2018-2023 Valerio Bozzolan
 # Boz Libre Hosting Panel
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
 # published by the Free Software Foundation, either version 3 of the
 # License, or (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 /*
  * This is the template for a link
  *
  * Called from
  * 	include/functions.php - the_link() function
  *
  * Available variables:
  * 	$title string e.g. "Home" - it will be escaped.
  * 	$url string e.g. "/"
  *      $classes string e.g. "disabled"
  * 	$args mixed
  */
 
+$classes = $classes ?? null;
+
 // unuseful when load directly
 defined( 'BOZ_PHP' ) or die;
 
 ?><a class="btn btn-default<?= HTML::spaced( $classes ) ?>" href="<?= esc_attr( $url ) ?>"><?= esc_html( $title ) ?></a>