public function setDefault()
 {
     if (!$this->isPostRequest()) {
         exit;
     }
     ThemeModel::getInstance()->setDefaultTheme();
     messages::add('Theme_ThemeRestored', ['name' => ThemeModel::getInstance()->getDefaultTheme()], 'success');
     $this->systemRedirect('/theme');
 }
<!DOCTYPE html>
<html>
<head>
    <title> phAdmin </title>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <?php 
$ph->include_system_css('themes/' . \ph\phAdmin\application\models\ThemeModel::getInstance()->getCurrentThemeFile())->include_system_css('skeleton.css')->include_system_css('common.css')->include_system_js_lib('jquery-2.1.4.min.js')->include_system_js_lib('bootstrap-3.3.5-dist/bootstrap.min.js');
?>
</head>

<body>

    <?php 
$this->renderTemplate('header');
?>

    <div class="container">
        <?php 
$this->renderContent();
?>
    </div>

    <?php 
$this->renderTemplate('footer');
?>

</body>
</html>