Change default navigation link class

<?php   
/*-------------------------------------------------------+
| PHPFusion Content Management System
| Copyright (C) 2002 - 2010 Nick Jones
| http://www.php-fusion.co.uk/
+--------------------------------------------------------+
| Filename: navigation_panel.php
| Author: Nick Jones (Digitanium)
+--------------------------------------------------------+
| This program is released as free software under the
| Affero GPL license. You can redistribute it and/or
| modify it under the terms of this license which you
| can read by viewing the included agpl.txt or online
| at www.gnu.org/licenses/agpl.html. Removal of this
| copyright header is strictly prohibited without
| written permission from the original author(s).
+--------------------------------------------------------*/
if (!defined("IN_FUSION")) { die("Access Denied"); }

$list_open = false;

openside($locale['global_001']);
$result = dbquery(
   "SELECT link_name, link_url, link_window, link_visibility FROM ".DB_SITE_LINKS."
   WHERE link_position='1' OR link_position='2' ORDER BY link_order"
);
if (dbrows($result)) {
   echo "<div id='navigation'>\n";
   while($data = dbarray($result)) {
      if (checkgroup($data['link_visibility'])) {
         if ($data['link_name'] != "---" && $data['link_url'] == "---") {
            if ($list_open) { echo "</ul>\n"; $list_open = false; }
            echo "<h2>".parseubb($data['link_name'], "b|i|u|color")."</h2>\n";
         } else if ($data['link_name'] == "---" && $data['link_url'] == "---") {
            if ($list_open) { echo "</ul>\n"; $list_open = false; }
            echo "<hr class='side-hr' />\n";
         } else {
            if (!$list_open) { echo "<ul>\n"; $list_open = true; }
            $link_target = ($data['link_window'] == "1" ? " target='_blank'" : "");
            if (strstr($data['link_url'], "http://") || strstr($data['link_url'], "https://")) {
               echo "<li><a href='".$data['link_url']."'".$link_target." class='side-nav'>".THEME_BULLET." <span>".parseubb($data['link_name'], "b|i|u|color")."</span></a></li>\n";
            } else {
               echo "<li><a href='".BASEDIR.$data['link_url']."'".$link_target." class='side-nav'>".THEME_BULLET." <span>".parseubb($data['link_name'], "b|i|u|color")."</span></a></li>\n";
            }
         }
      }
   }
   if ($list_open) { echo "</ul>\n"; }
   echo "</div>\n";
} else {
   echo $locale['global_002'];

}
closeside();
?>

echo "<li><a href='".$data['link_url']."'".$link_target." class='side'>".THEME_BULLET." <span>".parseubb($data['link_name'], "b|i|u|color")."</span></a></li>\n";

echo "<li><a href='".$data['link_url']."'".$link_target." class='side-nav'>".THEME_BULLET." <span>".parseubb($data['link_name'], "b|i|u|color")."</span></a></li>\n";