diff --git a/config.php b/config.php
index 7beda22..80aa5fd 100755
--- a/config.php
+++ b/config.php
@@ -19,6 +19,7 @@ $loader = new \Twig\Loader\FilesystemLoader(__DIR__ . '/templates');
 $twig = new \Twig\Environment($loader, [
     // 'cache' => __DIR__ . '/cache/twig', // Uncomment for production
     'debug' => true,
+    'max_recursion' => 100,
 ]);
 
 // --- Translation Setup ---
@@ -52,7 +53,8 @@ try {
     $categories = App\Models\Category::getAll($db);
     $items = App\Models\Item::getAll($db);
 
-    function buildTree($categories, $items, $parentId = null, &$visited = []) {
+    function buildTree($categories, $items, $parentId = null, &$visited = [], $depth = 0) {
+        if ($depth > 10) return []; // Prevent deep recursion
         $tree = [];
         foreach ($categories as $cat) {
             if ($cat['parent_id'] == $parentId && !in_array($cat['id'], $visited)) {
@@ -60,7 +62,7 @@ try {
                 $node = [
                     'id' => $cat['id'],
                     'name' => $cat['name'],
-                    'children' => buildTree($categories, $items, $cat['id'], $visited),
+                    'children' => buildTree($categories, $items, $cat['id'], $visited, $depth + 1),
                     'items' => []
                 ];
                 foreach ($items as $item) {
@@ -75,8 +77,33 @@ try {
     }
 
     $categoryTree = buildTree($categories, $items);
+
+    function renderTree($nodes, $depth = 0) {
+        if ($depth > 10) return '';
+        $html = '';
+        foreach ($nodes as $node) {
+            $html .= '<li>';
+            $html .= '<span class="category" onclick="toggleCategory(this)">' . htmlspecialchars($node['name']) . '</span>';
+            if (!empty($node['children'])) {
+                $html .= '<ul style="display: none;">';
+                $html .= renderTree($node['children'], $depth + 1);
+                $html .= '</ul>';
+            }
+            if (!empty($node['items'])) {
+                $html .= '<ul class="items">';
+                foreach ($node['items'] as $item) {
+                    $html .= '<li><a href="#" onclick="editItem(' . (int)$item['id'] . ')" class="item-link">' . htmlspecialchars($item['name']) . '</a></li>';
+                }
+                $html .= '</ul>';
+            }
+            $html .= '</li>';
+        }
+        return $html;
+    }
+
+    $sidebarHtml = '<ul class="category-tree">' . renderTree($categoryTree) . '</ul>';
 } catch (Exception $e) {
     error_log('Error building category tree: ' . $e->getMessage());
-    $categoryTree = [];
+    $sidebarHtml = '<ul class="nav flex-column nav-pills"><li class="nav-item"><a class="nav-link" href="#" data-route="/">Overview</a></li><li class="nav-item"><a class="nav-link" href="#" data-route="/categories">Categories</a></li><li class="nav-item"><a class="nav-link" href="#" data-route="/parts">Parts</a></li></ul>';
 }
-$twig->addGlobal('category_tree', $categoryTree);
+$twig->addGlobal('sidebar_html', $sidebarHtml);
diff --git a/templates/partials/sidebar.twig b/templates/partials/sidebar.twig
index bb9312d..5aeb3d7 100755
--- a/templates/partials/sidebar.twig
+++ b/templates/partials/sidebar.twig
@@ -1,27 +1 @@
-{% autoescape %}
-{% macro render_node(node) %}
-<li>
-    <span class="category" onclick="toggleCategory(this)">{{ node.name }}</span>
-    {% if node.children %}
-        <ul style="display: none;">
-        {% for child in node.children %}
-            {{ _self.render_node(child) }}
-        {% endfor %}
-        </ul>
-    {% endif %}
-    {% if node.items %}
-        <ul class="items">
-        {% for item in node.items %}
-            <li><a href="#" onclick="editItem({{ item.id }})" class="item-link">{{ item.name }}</a></li>
-        {% endfor %}
-        </ul>
-    {% endif %}
-</li>
-{% endmacro %}
-
-<ul class="category-tree">
-{% for node in category_tree %}
-    {{ _self.render_node(node) }}
-{% endfor %}
-</ul>
-{% endautoescape %}
\ No newline at end of file
+{{ sidebar_html|raw }}
\ No newline at end of file