Merge branch 'main' into develop

public/404.php

@@ -1,5 +1,5 @@
 <?php
-require_once 'includes/functions.php';
+require_once __DIR__ . '/../backend/includes/functions.php';
 
 // Page configuration
 $page_title = '404 - Seite nicht gefunden | HexaHost.de';
@@ -13,7 +13,7 @@ http_response_code(404);
 includeHeader($page_title, $page_description, $current_page);
 ?>
 
-<main>
+<main id="main-content">
     <section class="error-page">
         <div class="container">
             <div class="error-content glass-card">