我的CMS设计如何？有安全性，设计或其他问题吗？

<?php
    class cms {
        private $dbhost     = "";
        private $dbuser     = "";
        private $dbpass     = "";
        private $dbdb       = "";
        private $dbc;
        public $website;
        public $user;
        public $theme;

        function __construct() {
            $this->session();
            $this->getWebsite();
        }
        function connect() {
            $dbc = mysqli_connect($this->dbhost, $this->dbuser, $this->dbpass, $this->dbdb) or die("Error " . mysqli_error($dbc));
            return $dbc;
        }
        function session() {
            if(!isset($_SESSION)) {
                session_start();
            }
        }
        function getWebsite() {
            $dbc = $this->connect();
            $stmt = $dbc->prepare("SELECT * FROM website");
            $stmt->execute();
            $result = $stmt->get_result();
            $this->website = $result->fetch_assoc();
            $stmt->close();
            $this->theme = $this->website['theme'];
        }
    }
?>

<?php
    require_once('config/config.inc.php');
    $cms = new cms();
    include("template/" . $cms->theme . "/head.php");
    $moduleArray = array_diff(scandir('module/', 1), array('..', '.', 'admin'));

    if(($_SERVER['REQUEST_METHOD'] === 'GET' || $_SERVER['REQUEST_METHOD'] === 'POST') && !empty($_GET['page'])) {
        $p = $_GET['page'];
        $ext = ".inc.php";

        if (get_magic_quotes_gpc()) {
            $p = stripslashes($p);
        }

        if(in_array($p . $ext, $moduleArray)) { 
            include("module/" . $p . $ext);
        }
        else {
            header('Location: /');
        }
    } // end (GET || POST) && GET
    else {
        foreach($moduleArray as $module) {
            $name = substr($module, 0, -8);
            echo " <a href=\"index.php?page=$name\"> $name </a><br />";
        }
    } // end ELSE

    include("template/" . $cms->theme . "/foot.php");
?>

<?php
    $dbc = $cms->connect();

    if(isset($_GET['page'])) {
        if(isset($_GET['title'])) {
            $t = $_GET['title'];

            if (get_magic_quotes_gpc()) {
                $t = stripslashes($username);
            }

            if ($stmt = $dbc->prepare("SELECT title, content_main FROM pages WHERE url=?")) {       
                $stmt->bind_param('s', $t);
                $stmt->execute();
                $stmt->store_result();
                $stmt->bind_result($title, $content_main);

                if($stmt->fetch()) {
                    echo "<h2>$title</h2><p>$content_main</p>";
                }
                else {
                    echo "<h2>404</h2><p>The page doesn't exist!</p>";
                }

                $stmt->free_result();
                $stmt->close();
            }
            else {
                echo "error";
            }
        }
        else {
            if ($stmt = $dbc->prepare("SELECT title, url FROM pages")) {        
                $stmt->execute();
                $stmt->store_result();
                $stmt->bind_result($title, $url);

                while ($stmt->fetch()) {
                    echo "<a href=\"index.php?page=page&title=$url\">$title</a></br />";
                }

                $stmt->free_result();
                $stmt->close();
            }
        }
    }
    else {
        header('Location: ../');
    }
?>

namespace CMS;
class UserHandler {

}
class Mapper {

}
class CMSData {

}
/* In this below section, we instantiate each class according to the way we will pass their dependencies to the class. */

$CMSData     = new CMSData();
$Mapper      = new Mapper($CMSData);
$UserHandler = new UserHandler($CMSData, $Mapper);