diff --git a/admin.php b/admin.php
index 97630a9..f4ef93f 100644
--- a/admin.php
+++ b/admin.php
@@ -7,6 +7,7 @@ library_bootstrap();
 
 $documents = library_fetch_documents(false, []);
 $metrics = library_catalog_metrics();
+$lang = library_get_language();
 
 admin_render_header(library_trans('dashboard'), 'dashboard');
 ?>
@@ -18,7 +19,7 @@ admin_render_header(library_trans('dashboard'), 'dashboard');
             <div class="card-body">
                 <h6 class="text-uppercase text-secondary small fw-bold"><?= library_trans('total_documents') ?></h6>
                 <div class="d-flex align-items-center justify-content-between mt-3">
-                    <h2 class="display-6 fw-bold mb-0 text-primary"><?= number_format($metrics['total_documents']) ?></h2>
+                    <h2 class="display-6 fw-bold mb-0 text-primary"><?= number_format((int) ($metrics['total_count'] ?? 0)) ?></h2>
                     <i class="bi bi-file-earmark-text fs-1 text-primary opacity-25"></i>
                 </div>
             </div>
@@ -29,7 +30,7 @@ admin_render_header(library_trans('dashboard'), 'dashboard');
             <div class="card-body">
                 <h6 class="text-uppercase text-secondary small fw-bold"><?= library_trans('public_titles') ?></h6>
                 <div class="d-flex align-items-center justify-content-between mt-3">
-                    <h2 class="display-6 fw-bold mb-0 text-success"><?= number_format($metrics['public_documents']) ?></h2>
+                    <h2 class="display-6 fw-bold mb-0 text-success"><?= number_format((int) ($metrics['public_count'] ?? 0)) ?></h2>
                     <i class="bi bi-globe fs-1 text-success opacity-25"></i>
                 </div>
             </div>
@@ -38,10 +39,10 @@ admin_render_header(library_trans('dashboard'), 'dashboard');
     <div class="col-md-4">
         <div class="card shadow-sm border-0 h-100">
             <div class="card-body">
-                <h6 class="text-uppercase text-secondary small fw-bold"><?= library_trans('total_downloads') ?></h6>
+                <h6 class="text-uppercase text-secondary small fw-bold"><?= library_trans('private_titles') ?></h6>
                 <div class="d-flex align-items-center justify-content-between mt-3">
-                    <h2 class="display-6 fw-bold mb-0 text-info"><?= number_format($metrics['total_downloads']) ?></h2>
-                    <i class="bi bi-download fs-1 text-info opacity-25"></i>
+                    <h2 class="display-6 fw-bold mb-0 text-info"><?= number_format((int) ($metrics['private_count'] ?? 0)) ?></h2>
+                    <i class="bi bi-lock fs-1 text-info opacity-25"></i>
                 </div>
             </div>
         </div>
@@ -67,28 +68,34 @@ admin_render_header(library_trans('dashboard'), 'dashboard');
                     </thead>
                     <tbody>
                         <?php if (empty($documents)): ?>
-                            <tr><td colspan="4" class="text-center py-5 text-muted">No documents found.</td></tr>
+                            <tr><td colspan="4" class="text-center py-5 text-muted"><?= library_trans('no_documents_found') ?></td></tr>
                         <?php else: ?>
                             <?php foreach (array_slice($documents, 0, 10) as $doc): ?>
+                                <?php
+                                    $title = library_localized_document_title($doc, $lang);
+                                    $typeLabel = library_localized_value($doc['type_en'] ?? null, $doc['type_ar'] ?? null, $lang);
+                                    $categoryLabel = library_localized_value($doc['cat_en'] ?? $doc['category'] ?? null, $doc['cat_ar'] ?? $doc['category_ar'] ?? null, $lang);
+                                ?>
                                 <tr>
                                     <td class="ps-4">
-                                        <div class="fw-medium text-dark"><?= h($doc['title_en']) ?></div>
-                                        <div class="small text-muted" dir="rtl"><?= h($doc['title_ar']) ?></div>
+                                        <div class="fw-medium text-dark" dir="<?= library_text_dir($title, $lang) ?>"><?= h($title) ?></div>
                                         <?php if (!empty($doc['author'])): ?>
                                             <div class="small text-primary mt-1"><i class="bi bi-person me-1"></i><?= h($doc['author']) ?></div>
                                         <?php endif; ?>
                                     </td>
                                     <td>
-                                        <?php if (!empty($doc['type_en'])): ?>
-                                            <span class="badge bg-info bg-opacity-10 text-info border border-info border-opacity-25 mb-1"><?= h($doc['type_en']) ?></span><br>
+                                        <?php if ($typeLabel !== ''): ?>
+                                            <span class="badge bg-info bg-opacity-10 text-info border border-info border-opacity-25 mb-1" dir="<?= library_text_dir($typeLabel, $lang) ?>"><?= h($typeLabel) ?></span><br>
+                                        <?php endif; ?>
+                                        <?php if ($categoryLabel !== ''): ?>
+                                            <span class="badge bg-light text-dark border" dir="<?= library_text_dir($categoryLabel, $lang) ?>">
+                                                <?= h($categoryLabel) ?>
+                                            </span>
                                         <?php endif; ?>
-                                        <span class="badge bg-light text-dark border">
-                                            <?= h($doc['cat_en'] ?? $doc['category']) ?>
-                                        </span>
                                     </td>
                                     <td>
                                         <span class="badge bg-<?= $doc['visibility'] === 'public' ? 'success' : 'secondary' ?>">
-                                            <?= h($doc['visibility']) ?>
+                                            <?= h(library_visibility_label($doc['visibility'])) ?>
                                         </span>
                                     </td>
                                     <td class="text-end pe-4">
diff --git a/admin_categories.php b/admin_categories.php
index e7cea46..45480cc 100644
--- a/admin_categories.php
+++ b/admin_categories.php
@@ -17,28 +17,28 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             $nameEn = trim($_POST['name_en'] ?? '');
             $nameAr = trim($_POST['name_ar'] ?? '');
             if (!$nameEn || !$nameAr) {
-                throw new RuntimeException('Both English and Arabic names are required for Category.');
+                throw new RuntimeException(library_trans('category_name_required'));
             }
             library_create_category($nameEn, $nameAr);
-            library_set_flash('success', 'Category created successfully.');
+            library_set_flash('success', library_trans('category_created_success'));
             header('Location: /admin_categories.php');
             exit;
         } elseif ($action === 'update_category') {
             $nameEn = trim($_POST['name_en'] ?? '');
             $nameAr = trim($_POST['name_ar'] ?? '');
             if (!$id || !$nameEn || !$nameAr) {
-                throw new RuntimeException('ID, English name, and Arabic name are required.');
+                throw new RuntimeException(library_trans('category_update_required'));
             }
             library_update_category($id, $nameEn, $nameAr);
-            library_set_flash('success', 'Category updated successfully.');
+            library_set_flash('success', library_trans('category_updated_success'));
             header('Location: /admin_categories.php');
             exit;
         } elseif ($action === 'delete_category') {
             if (!$id) {
-                throw new RuntimeException('Invalid Category ID.');
+                throw new RuntimeException(library_trans('invalid_category_id'));
             }
             library_delete_category($id);
-            library_set_flash('success', 'Category deleted successfully.');
+            library_set_flash('success', library_trans('category_deleted_success'));
             header('Location: /admin_categories.php');
             exit;
         }
@@ -57,6 +57,7 @@ $result = library_get_categories_paginated($search, $limit, $offset);
 $categories = $result['data'];
 $totalCategories = $result['total'];
 $totalPages = (int)ceil($totalCategories / $limit);
+$lang = library_get_language();
 
 admin_render_header(library_trans('categories'), 'categories');
 ?>
@@ -108,8 +109,8 @@ admin_render_header(library_trans('categories'), 'categories');
                         <?php foreach ($categories as $cat): ?>
                             <tr>
                                 <td class="ps-4">
-                                    <div class="fw-medium text-dark"><?= h($cat['name_en']) ?></div>
-                                    <small class="text-muted"><?= h($cat['name_ar']) ?></small>
+                                    <?php $categoryName = library_localized_value($cat['name_en'] ?? null, $cat['name_ar'] ?? null, $lang); ?>
+                                    <div class="fw-medium text-dark" dir="<?= library_text_dir($categoryName, $lang) ?>"><?= h($categoryName) ?></div>
                                 </td>
                                 <td class="text-end pe-4">
                                     <button class="btn btn-sm btn-outline-secondary me-1" 
@@ -155,7 +156,7 @@ admin_render_header(library_trans('categories'), 'categories');
                 <label class="form-label"><?= library_trans('name_en') ?></label>
                 <div class="input-group">
                     <input type="text" class="form-control" name="name_en" id="cat_name_en" required>
-                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('cat_name_en', 'cat_name_ar', 'Arabic')" title="Translate to Arabic">
+                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('cat_name_en', 'cat_name_ar', 'Arabic')" title="<?= library_trans('translation_to_arabic') ?>">
                         <i class="bi bi-translate"></i>
                     </button>
                 </div>
@@ -164,7 +165,7 @@ admin_render_header(library_trans('categories'), 'categories');
                 <label class="form-label"><?= library_trans('name_ar') ?></label>
                 <div class="input-group">
                     <input type="text" class="form-control" name="name_ar" id="cat_name_ar" dir="rtl" required>
-                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('cat_name_ar', 'cat_name_en', 'English')" title="Translate to English">
+                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('cat_name_ar', 'cat_name_en', 'English')" title="<?= library_trans('translation_to_english') ?>">
                         <i class="bi bi-translate"></i>
                     </button>
                 </div>
diff --git a/admin_documents.php b/admin_documents.php
index 214f122..322eba3 100644
--- a/admin_documents.php
+++ b/admin_documents.php
@@ -26,23 +26,23 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         try {
             if ($action === 'create_document') {
                 library_create_document($_POST, $_FILES['document_file'] ?? [], $_FILES['cover_file'] ?? []);
-                library_set_flash('success', 'Document created successfully.');
+                library_set_flash('success', library_trans('document_created_success'));
                 header('Location: /admin_documents.php');
                 exit;
             } elseif ($action === 'update_document') {
                 if (!$id) {
-                    throw new RuntimeException('Invalid Document ID.');
+                    throw new RuntimeException(library_trans('invalid_document_id'));
                 }
                 library_update_document($id, $_POST, $_FILES['document_file'] ?? [], $_FILES['cover_file'] ?? []);
-                library_set_flash('success', 'Document updated successfully.');
+                library_set_flash('success', library_trans('document_updated_success'));
                 header('Location: /admin_documents.php');
                 exit;
             } elseif ($action === 'delete_document') {
                 if (!$id) {
-                    throw new RuntimeException('Invalid Document ID.');
+                    throw new RuntimeException(library_trans('invalid_document_id'));
                 }
                 library_delete_document($id);
-                library_set_flash('success', 'Document deleted successfully.');
+                library_set_flash('success', library_trans('document_deleted_success'));
                 header('Location: /admin_documents.php');
                 exit;
             }
@@ -67,13 +67,14 @@ $totalPages = (int)ceil($totalDocuments / $limit);
 $categories = library_get_categories();
 $allSubcategories = library_get_subcategories(null);
 $types = library_get_types();
+$lang = library_get_language();
 
 admin_render_header(library_trans('material_entry'), 'documents');
 ?>
 <!-- Page Content -->
 <?php if ($errors): ?>
     <div class="alert alert-danger">
-        <h6 class="alert-heading fw-bold"><i class="bi bi-exclamation-triangle-fill me-2"></i>Submission Error</h6>
+        <h6 class="alert-heading fw-bold"><i class="bi bi-exclamation-triangle-fill me-2"></i><?= library_trans('submission_error') ?></h6>
         <ul class="mb-0 ps-3">
             <?php foreach ($errors as $e): ?>
                 <li><?= h($e) ?></li>
@@ -124,7 +125,7 @@ admin_render_header(library_trans('material_entry'), 'documents');
                 </thead>
                 <tbody>
                     <?php if (empty($documents)): ?>
-                        <tr><td colspan="6" class="text-center py-5 text-muted">No documents found.</td></tr>
+                        <tr><td colspan="6" class="text-center py-5 text-muted"><?= library_trans('no_documents_found') ?></td></tr>
                     <?php else: ?>
                         <?php foreach ($documents as $doc): ?>
                             <tr>
@@ -139,20 +140,25 @@ admin_render_header(library_trans('material_entry'), 'documents');
                                     <?php endif; ?>
                                 </td>
                                 <td>
-                                    <div class="fw-medium text-dark"><?= h($doc['title_en']) ?></div>
-                                    <div class="small text-muted" dir="rtl"><?= h($doc['title_ar']) ?></div>
+                                    <?php $title = library_localized_document_title($doc, $lang); ?>
+                                    <div class="fw-medium text-dark" dir="<?= library_text_dir($title, $lang) ?>"><?= h($title) ?></div>
                                     <?php if (!empty($doc['author'])): ?>
                                         <div class="small text-primary mt-1"><i class="bi bi-person me-1"></i><?= h($doc['author']) ?></div>
                                     <?php endif; ?>
                                 </td>
                                 <td>
-                                    <?php if (!empty($doc['type_en'])): ?>
-                                        <span class="badge bg-info bg-opacity-10 text-info border border-info border-opacity-25 mb-1"><?= h($doc['type_en']) ?></span><br>
+                                    <?php $typeLabel = library_localized_value($doc['type_en'] ?? null, $doc['type_ar'] ?? null, $lang); ?>
+                                    <?php if ($typeLabel !== ''): ?>
+                                        <span class="badge bg-info bg-opacity-10 text-info border border-info border-opacity-25 mb-1" dir="<?= library_text_dir($typeLabel, $lang) ?>"><?= h($typeLabel) ?></span><br>
                                     <?php endif; ?>
-                                    <span class="badge bg-light text-dark border"><?= h($doc['cat_en'] ?? $doc['category']) ?></span>
-                                    <?php if (!empty($doc['sub_en'])): ?>
+                                    <?php $categoryLabel = library_localized_value($doc['cat_en'] ?? $doc['category'] ?? null, $doc['cat_ar'] ?? $doc['category_ar'] ?? null, $lang); ?>
+                                    <?php if ($categoryLabel !== ''): ?>
+                                        <span class="badge bg-light text-dark border" dir="<?= library_text_dir($categoryLabel, $lang) ?>"><?= h($categoryLabel) ?></span>
+                                    <?php endif; ?>
+                                    <?php $subcategoryLabel = library_localized_value($doc['sub_en'] ?? $doc['sub_category'] ?? null, $doc['sub_ar'] ?? $doc['sub_category_ar'] ?? null, $lang); ?>
+                                    <?php if ($subcategoryLabel !== ''): ?>
                                         <i class="bi bi-chevron-right text-muted small"></i>
-                                        <span class="badge bg-light text-dark border"><?= h($doc['sub_en']) ?></span>
+                                        <span class="badge bg-light text-dark border" dir="<?= library_text_dir($subcategoryLabel, $lang) ?>"><?= h($subcategoryLabel) ?></span>
                                     <?php endif; ?>
                                 </td>
                                 <td><?= h((string)$doc['publish_year']) ?></td>
@@ -208,14 +214,14 @@ admin_render_header(library_trans('material_entry'), 'documents');
                     <label class="form-label small fw-bold text-uppercase text-muted"><?= library_trans('name_en') ?> <span class="text-danger">*</span></label>
                     <div class="input-group">
                         <input type="text" class="form-control" name="title_en" id="doc_title_en" required>
-                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_title_en', 'doc_title_ar', 'Arabic')"><i class="bi bi-translate"></i></button>
+                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_title_en', 'doc_title_ar', 'Arabic')" title="<?= library_trans('translation_to_arabic') ?>"><i class="bi bi-translate"></i></button>
                     </div>
                 </div>
                 <div class="col-md-6">
                     <label class="form-label small fw-bold text-uppercase text-muted"><?= library_trans('name_ar') ?></label>
                     <div class="input-group">
                         <input type="text" class="form-control" name="title_ar" id="doc_title_ar" dir="rtl">
-                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_title_ar', 'doc_title_en', 'English')"><i class="bi bi-translate"></i></button>
+                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_title_ar', 'doc_title_en', 'English')" title="<?= library_trans('translation_to_english') ?>"><i class="bi bi-translate"></i></button>
                     </div>
                 </div>
 
@@ -239,7 +245,8 @@ admin_render_header(library_trans('material_entry'), 'documents');
                     <select class="form-select" name="type_id" id="doc_type_id">
                         <option value=""><?= library_trans('select_type') ?></option>
                         <?php foreach ($types as $t): ?>
-                            <option value="<?= $t['id'] ?>"><?= h($t['name_en']) ?> / <?= h($t['name_ar']) ?></option>
+                            <?php $typeName = library_localized_value($t['name_en'] ?? null, $t['name_ar'] ?? null, $lang); ?>
+                            <option value="<?= $t['id'] ?>" dir="<?= library_text_dir($typeName, $lang) ?>"><?= h($typeName) ?></option>
                         <?php endforeach; ?>
                     </select>
                 </div>
@@ -248,7 +255,8 @@ admin_render_header(library_trans('material_entry'), 'documents');
                     <select class="form-select" name="category_id" id="doc_category_id" onchange="updateSubcategories()">
                         <option value=""><?= library_trans('select_category') ?></option>
                         <?php foreach ($categories as $c): ?>
-                            <option value="<?= $c['id'] ?>"><?= h($c['name_en']) ?> / <?= h($c['name_ar']) ?></option>
+                            <?php $categoryName = library_localized_value($c['name_en'] ?? null, $c['name_ar'] ?? null, $lang); ?>
+                            <option value="<?= $c['id'] ?>" dir="<?= library_text_dir($categoryName, $lang) ?>"><?= h($categoryName) ?></option>
                         <?php endforeach; ?>
                     </select>
                 </div>
@@ -274,14 +282,14 @@ admin_render_header(library_trans('material_entry'), 'documents');
                     <label class="form-label small fw-bold text-uppercase text-muted"><?= library_trans('summary_en') ?></label>
                     <div class="input-group">
                         <textarea class="form-control" name="summary_en" id="doc_summary_en" rows="3"></textarea>
-                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_summary_en', 'doc_summary_ar', 'Arabic')"><i class="bi bi-translate"></i></button>
+                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_summary_en', 'doc_summary_ar', 'Arabic')" title="<?= library_trans('translation_to_arabic') ?>"><i class="bi bi-translate"></i></button>
                     </div>
                 </div>
                 <div class="col-md-6">
                     <label class="form-label small fw-bold text-uppercase text-muted"><?= library_trans('summary_ar') ?></label>
                     <div class="input-group">
                         <textarea class="form-control" name="summary_ar" id="doc_summary_ar" rows="3" dir="rtl"></textarea>
-                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_summary_ar', 'doc_summary_en', 'English')"><i class="bi bi-translate"></i></button>
+                        <button class="btn btn-outline-secondary" type="button" onclick="translateText('doc_summary_ar', 'doc_summary_en', 'English')" title="<?= library_trans('translation_to_english') ?>"><i class="bi bi-translate"></i></button>
                     </div>
                 </div>
 
@@ -290,7 +298,7 @@ admin_render_header(library_trans('material_entry'), 'documents');
                     <label class="form-label small fw-bold text-uppercase text-muted"><?= library_trans('cover_image') ?></label>
                     <input class="form-control" type="file" name="cover_file" accept="image/*">
                     <div id="current_cover_preview" class="mt-2 d-none">
-                        <small class="text-muted d-block mb-1">Current Cover:</small>
+                        <small class="text-muted d-block mb-1"><?= library_trans('current_cover') ?></small>
                         <img src="" class="rounded border" style="height: 60px;">
                     </div>
                 </div>
@@ -311,8 +319,8 @@ admin_render_header(library_trans('material_entry'), 'documents');
                             <div class="row">
                                 <div class="col-md-3">
                                     <select class="form-select form-select-sm" name="visibility" id="doc_visibility">
-                                        <option value="public">Public</option>
-                                        <option value="private">Private</option>
+                                        <option value="public"><?= library_trans('visibility_public') ?></option>
+                                        <option value="private"><?= library_trans('visibility_private') ?></option>
                                     </select>
                                 </div>
                                 <div class="col-md-9 d-flex align-items-center gap-3">
@@ -347,6 +355,7 @@ admin_render_header(library_trans('material_entry'), 'documents');
 
 <script>
     let documentModal;
+    const currentLang = <?= json_encode($lang) ?>;
     const allSubcategories = <?= json_encode($allSubcategories) ?>;
 
     document.addEventListener('DOMContentLoaded', function() {
@@ -372,7 +381,7 @@ admin_render_header(library_trans('material_entry'), 'documents');
             subs.forEach(s => {
                 const opt = document.createElement('option');
                 opt.value = s.id;
-                opt.textContent = s.name_en + ' / ' + s.name_ar;
+                opt.textContent = currentLang === 'ar' ? (s.name_ar || s.name_en || '') : (s.name_en || s.name_ar || '');
                 if (selectedSubId && s.id == selectedSubId) opt.selected = true;
                 subSelect.appendChild(opt);
             });
diff --git a/admin_subcategories.php b/admin_subcategories.php
index 7ddcd6d..85087e8 100644
--- a/admin_subcategories.php
+++ b/admin_subcategories.php
@@ -18,10 +18,10 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             $nameEn = trim($_POST['name_en'] ?? '');
             $nameAr = trim($_POST['name_ar'] ?? '');
             if (!$catId || !$nameEn || !$nameAr) {
-                throw new RuntimeException('Category, English name, and Arabic name are required.');
+                throw new RuntimeException(library_trans('subcategory_name_required'));
             }
             library_create_subcategory($catId, $nameEn, $nameAr);
-            library_set_flash('success', 'Subcategory created successfully.');
+            library_set_flash('success', library_trans('subcategory_created_success'));
             header('Location: /admin_subcategories.php');
             exit;
         } elseif ($action === 'update_subcategory') {
@@ -29,18 +29,18 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             $nameEn = trim($_POST['name_en'] ?? '');
             $nameAr = trim($_POST['name_ar'] ?? '');
             if (!$id || !$catId || !$nameEn || !$nameAr) {
-                throw new RuntimeException('ID, Category, English name, and Arabic name are required.');
+                throw new RuntimeException(library_trans('subcategory_update_required'));
             }
             library_update_subcategory($id, $catId, $nameEn, $nameAr);
-            library_set_flash('success', 'Subcategory updated successfully.');
+            library_set_flash('success', library_trans('subcategory_updated_success'));
             header('Location: /admin_subcategories.php');
             exit;
         } elseif ($action === 'delete_subcategory') {
             if (!$id) {
-                throw new RuntimeException('Invalid Subcategory ID.');
+                throw new RuntimeException(library_trans('invalid_subcategory_id'));
             }
             library_delete_subcategory($id);
-            library_set_flash('success', 'Subcategory deleted successfully.');
+            library_set_flash('success', library_trans('subcategory_deleted_success'));
             header('Location: /admin_subcategories.php');
             exit;
         }
@@ -63,6 +63,7 @@ $result = library_get_subcategories_paginated(null, $search, $limit, $offset);
 $allSubcategories = $result['data'];
 $totalSubcategories = $result['total'];
 $totalPages = (int)ceil($totalSubcategories / $limit);
+$lang = library_get_language();
 
 admin_render_header(library_trans('subcategories'), 'subcategories');
 ?>
@@ -113,21 +114,21 @@ admin_render_header(library_trans('subcategories'), 'subcategories');
                         <tr><td colspan="3" class="text-center py-5 text-muted"><?= library_trans('no_subcategories_found') ?></td></tr>
                     <?php else: ?>
                         <?php foreach ($allSubcategories as $sub): 
-                            $parentName = 'Unknown';
+                            $parentName = library_trans('unknown');
                             foreach ($categories as $c) {
                                 if ($c['id'] == $sub['category_id']) {
-                                    $parentName = $c['name_en'] . ' / ' . $c['name_ar']; // Show bilingual name for context
+                                    $parentName = library_localized_value($c['name_en'] ?? null, $c['name_ar'] ?? null, $lang, library_trans('unknown'));
                                     break;
                                 }
                             }
                         ?>
                             <tr>
                                 <td class="ps-4">
-                                    <div class="fw-medium text-dark"><?= h($sub['name_en']) ?></div>
-                                    <small class="text-muted"><?= h($sub['name_ar']) ?></small>
+                                    <?php $subName = library_localized_value($sub['name_en'] ?? null, $sub['name_ar'] ?? null, $lang); ?>
+                                    <div class="fw-medium text-dark" dir="<?= library_text_dir($subName, $lang) ?>"><?= h($subName) ?></div>
                                 </td>
                                 <td>
-                                    <span class="badge bg-light text-dark border"><?= h($parentName) ?></span>
+                                    <span class="badge bg-light text-dark border" dir="<?= library_text_dir($parentName, $lang) ?>"><?= h($parentName) ?></span>
                                 </td>
                                 <td class="text-end pe-4">
                                     <button class="btn btn-sm btn-outline-secondary me-1" 
@@ -175,7 +176,8 @@ admin_render_header(library_trans('subcategories'), 'subcategories');
                 <select class="form-select" name="category_id" id="sub_category_id" required>
                     <option value=""><?= library_trans('select_category') ?></option>
                     <?php foreach ($categories as $cat): ?>
-                        <option value="<?= $cat['id'] ?>"><?= h($cat['name_en']) ?> / <?= h($cat['name_ar']) ?></option>
+                        <?php $categoryName = library_localized_value($cat['name_en'] ?? null, $cat['name_ar'] ?? null, $lang); ?>
+                        <option value="<?= $cat['id'] ?>" dir="<?= library_text_dir($categoryName, $lang) ?>"><?= h($categoryName) ?></option>
                     <?php endforeach; ?>
                 </select>
             </div>
@@ -183,7 +185,7 @@ admin_render_header(library_trans('subcategories'), 'subcategories');
                 <label class="form-label"><?= library_trans('name_en') ?></label>
                 <div class="input-group">
                     <input type="text" class="form-control" name="name_en" id="sub_name_en" required>
-                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('sub_name_en', 'sub_name_ar', 'Arabic')" title="Translate to Arabic">
+                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('sub_name_en', 'sub_name_ar', 'Arabic')" title="<?= library_trans('translation_to_arabic') ?>">
                         <i class="bi bi-translate"></i>
                     </button>
                 </div>
@@ -192,7 +194,7 @@ admin_render_header(library_trans('subcategories'), 'subcategories');
                 <label class="form-label"><?= library_trans('name_ar') ?></label>
                 <div class="input-group">
                     <input type="text" class="form-control" name="name_ar" id="sub_name_ar" dir="rtl" required>
-                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('sub_name_ar', 'sub_name_en', 'English')" title="Translate to English">
+                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('sub_name_ar', 'sub_name_en', 'English')" title="<?= library_trans('translation_to_english') ?>">
                         <i class="bi bi-translate"></i>
                     </button>
                 </div>
diff --git a/admin_types.php b/admin_types.php
index 973c885..f3eadd7 100644
--- a/admin_types.php
+++ b/admin_types.php
@@ -17,28 +17,28 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             $nameEn = trim($_POST['name_en'] ?? '');
             $nameAr = trim($_POST['name_ar'] ?? '');
             if (!$nameEn || !$nameAr) {
-                throw new RuntimeException('Both English and Arabic names are required for Type.');
+                throw new RuntimeException(library_trans('type_name_required'));
             }
             library_create_type($nameEn, $nameAr);
-            library_set_flash('success', 'Type created successfully.');
+            library_set_flash('success', library_trans('type_created_success'));
             header('Location: /admin_types.php');
             exit;
         } elseif ($action === 'update_type') {
             $nameEn = trim($_POST['name_en'] ?? '');
             $nameAr = trim($_POST['name_ar'] ?? '');
             if (!$id || !$nameEn || !$nameAr) {
-                throw new RuntimeException('ID, English name, and Arabic name are required.');
+                throw new RuntimeException(library_trans('type_update_required'));
             }
             library_update_type($id, $nameEn, $nameAr);
-            library_set_flash('success', 'Type updated successfully.');
+            library_set_flash('success', library_trans('type_updated_success'));
             header('Location: /admin_types.php');
             exit;
         } elseif ($action === 'delete_type') {
             if (!$id) {
-                throw new RuntimeException('Invalid Type ID.');
+                throw new RuntimeException(library_trans('invalid_type_id'));
             }
             library_delete_type($id);
-            library_set_flash('success', 'Type deleted successfully.');
+            library_set_flash('success', library_trans('type_deleted_success'));
             header('Location: /admin_types.php');
             exit;
         }
@@ -57,6 +57,7 @@ $result = library_get_types_paginated($search, $limit, $offset);
 $types = $result['data'];
 $totalTypes = $result['total'];
 $totalPages = (int)ceil($totalTypes / $limit);
+$lang = library_get_language();
 
 admin_render_header(library_trans('types'), 'types');
 ?>
@@ -108,8 +109,8 @@ admin_render_header(library_trans('types'), 'types');
                         <?php foreach ($types as $type): ?>
                             <tr>
                                 <td class="ps-4">
-                                    <div class="fw-medium text-dark"><?= h($type['name_en']) ?></div>
-                                    <small class="text-muted"><?= h($type['name_ar']) ?></small>
+                                    <?php $typeName = library_localized_value($type['name_en'] ?? null, $type['name_ar'] ?? null, $lang); ?>
+                                    <div class="fw-medium text-dark" dir="<?= library_text_dir($typeName, $lang) ?>"><?= h($typeName) ?></div>
                                 </td>
                                 <td class="text-end pe-4">
                                     <button class="btn btn-sm btn-outline-secondary me-1" 
@@ -155,7 +156,7 @@ admin_render_header(library_trans('types'), 'types');
                 <label class="form-label"><?= library_trans('name_en') ?></label>
                 <div class="input-group">
                     <input type="text" class="form-control" name="name_en" id="type_name_en" required>
-                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('type_name_en', 'type_name_ar', 'Arabic')" title="Translate to Arabic">
+                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('type_name_en', 'type_name_ar', 'Arabic')" title="<?= library_trans('translation_to_arabic') ?>">
                         <i class="bi bi-translate"></i>
                     </button>
                 </div>
@@ -164,7 +165,7 @@ admin_render_header(library_trans('types'), 'types');
                 <label class="form-label"><?= library_trans('name_ar') ?></label>
                 <div class="input-group">
                     <input type="text" class="form-control" name="name_ar" id="type_name_ar" dir="rtl" required>
-                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('type_name_ar', 'type_name_en', 'English')" title="Translate to English">
+                    <button class="btn btn-outline-secondary" type="button" onclick="translateText('type_name_ar', 'type_name_en', 'English')" title="<?= library_trans('translation_to_english') ?>">
                         <i class="bi bi-translate"></i>
                     </button>
                 </div>
diff --git a/assets/css/custom.css b/assets/css/custom.css
index c477488..f97c67a 100644
--- a/assets/css/custom.css
+++ b/assets/css/custom.css
@@ -390,4 +390,103 @@ footer a {
 
 #flipbook-toolbar button:active {
     transform: scale(0.95);
-}
\ No newline at end of file
+}
+
+.catalog-card {
+    display: grid;
+    grid-template-columns: 128px minmax(0, 1fr);
+    gap: 1.25rem;
+    align-items: stretch;
+}
+
+.catalog-card-media {
+    display: flex;
+}
+
+.catalog-card-cover {
+    width: 128px;
+    min-width: 128px;
+    height: 176px;
+    object-fit: cover;
+    border-radius: var(--radius-md);
+    border: 1px solid var(--border);
+    background: var(--surface-muted);
+    box-shadow: var(--shadow-sm);
+}
+
+.catalog-card-cover-placeholder {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    color: var(--text-secondary);
+    font-size: 0.9rem;
+    font-weight: 600;
+    text-transform: uppercase;
+    letter-spacing: 0.06em;
+}
+
+.catalog-card-body {
+    min-width: 0;
+    display: flex;
+    flex-direction: column;
+    justify-content: center;
+}
+
+.catalog-card-title,
+.catalog-card-title-alt {
+    overflow-wrap: anywhere;
+}
+
+.catalog-card-title-alt {
+    font-size: 0.96rem;
+}
+
+.catalog-card-badges {
+    position: relative;
+    z-index: 1;
+}
+
+.catalog-card-meta {
+    display: grid;
+    gap: 0.65rem;
+}
+
+.catalog-card-meta > div {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.35rem;
+}
+
+.catalog-card-label {
+    min-width: 3.75rem;
+    color: var(--text);
+    font-weight: 600;
+}
+
+@media (max-width: 767.98px) {
+    .catalog-card {
+        grid-template-columns: 1fr;
+    }
+
+    .catalog-card-media {
+        justify-content: center;
+    }
+
+    .catalog-card-body {
+        text-align: start;
+    }
+}
+
+.topbar-lang-switch {
+    border-radius: 999px;
+    padding-inline: 0.9rem;
+    font-weight: 700;
+    line-height: 1.2;
+}
+
+.topbar-lang-switch:hover,
+.topbar-lang-switch:focus {
+    background: var(--accent);
+    border-color: var(--accent);
+    color: #fff;
+}
diff --git a/document.php b/document.php
index daea541..23b2f9f 100644
--- a/document.php
+++ b/document.php
@@ -11,15 +11,105 @@ $context = ($_GET['context'] ?? '') === 'admin' ? 'admin' : 'public';
 $publicOnly = $context !== 'admin';
 $document = $documentId > 0 ? library_fetch_document($documentId, $publicOnly) : null;
 
+$lang = library_get_language();
+$pageCopy = [
+    'en' => [
+        'not_found_title' => 'Document not found',
+        'not_found_description' => 'The requested library document could not be found.',
+        'not_found_copy' => 'This item is unavailable or private.',
+        'go_back' => 'Go back',
+        'back_to_admin' => 'Back to Admin Studio',
+        'back_to_catalog' => 'Back to catalog',
+        'detail_fallback' => 'Document detail',
+        'meta_description' => 'Read the document online, review its metadata, and see the selected-language summary and description.',
+        'author' => 'Author',
+        'views' => 'Views',
+        'file' => 'File',
+        'unknown_author' => 'Unknown author',
+        'unavailable' => 'Unavailable',
+        'reader_kicker' => 'Online reader',
+        'reader_title' => 'Read in the browser',
+        'open_fullscreen' => 'Open fullscreen',
+        'open_file' => 'Open file',
+        'private_item' => 'Private item',
+        'private_copy' => 'This title is marked as login-required by the admin, so it stays hidden from the public reading experience.',
+        'loading_book' => 'Loading book...',
+        'page' => 'Page',
+        'previous_page' => 'Previous page',
+        'next_page' => 'Next page',
+        'document_stored' => 'Document stored',
+        'document_stored_copy' => 'This file type is stored successfully, but inline reading is optimized for PDF in this first slice.',
+        'download_or_open' => 'Download / open file',
+        'no_file_title' => 'No file attached',
+        'no_file_copy' => 'Upload a file from the Admin Studio to enable reading.',
+        'summary_kicker' => 'AI summary',
+        'summary_title' => 'Quick summary',
+        'regenerate' => 'Regenerate',
+        'generate' => 'Generate',
+        'no_summary' => 'No summary yet for the selected language. Click Generate to create one from the document content.',
+        'metadata_kicker' => 'Metadata',
+        'metadata_title' => 'Catalog notes',
+        'published' => 'Published',
+        'tags' => 'Tags',
+        'size' => 'Size',
+        'description_kicker' => 'Description',
+        'description_title' => 'Source text used by AI',
+        'no_excerpt' => 'No excerpt yet for the selected language.',
+    ],
+    'ar' => [
+        'not_found_title' => 'المستند غير موجود',
+        'not_found_description' => 'تعذر العثور على مستند المكتبة المطلوب.',
+        'not_found_copy' => 'هذا العنصر غير متاح أو خاص.',
+        'go_back' => 'العودة',
+        'back_to_admin' => 'العودة إلى استوديو الإدارة',
+        'back_to_catalog' => 'العودة إلى الفهرس',
+        'detail_fallback' => 'تفاصيل المستند',
+        'meta_description' => 'اقرأ المستند عبر الإنترنت، وراجع بياناته الوصفية، وشاهد الملخص والوصف وفق اللغة المختارة.',
+        'author' => 'المؤلف',
+        'views' => 'المشاهدات',
+        'file' => 'الملف',
+        'unknown_author' => 'مؤلف غير معروف',
+        'unavailable' => 'غير متاح',
+        'reader_kicker' => 'القارئ الإلكتروني',
+        'reader_title' => 'اقرأ داخل المتصفح',
+        'open_fullscreen' => 'فتح بملء الشاشة',
+        'open_file' => 'فتح الملف',
+        'private_item' => 'عنصر خاص',
+        'private_copy' => 'هذا العنوان محدد من قبل المشرف كمحتوى يتطلب تسجيل الدخول، لذلك يظل مخفياً عن تجربة القراءة العامة.',
+        'loading_book' => 'جارٍ تحميل الكتاب...',
+        'page' => 'الصفحة',
+        'previous_page' => 'الصفحة السابقة',
+        'next_page' => 'الصفحة التالية',
+        'document_stored' => 'تم حفظ المستند',
+        'document_stored_copy' => 'تم حفظ هذا النوع من الملفات بنجاح، لكن القراءة المضمنة مهيأة لملفات PDF في هذه النسخة الأولى.',
+        'download_or_open' => 'تنزيل / فتح الملف',
+        'no_file_title' => 'لا يوجد ملف مرفق',
+        'no_file_copy' => 'ارفع ملفاً من استوديو الإدارة لتفعيل القراءة.',
+        'summary_kicker' => 'ملخص الذكاء الاصطناعي',
+        'summary_title' => 'ملخص سريع',
+        'regenerate' => 'إعادة التوليد',
+        'generate' => 'توليد',
+        'no_summary' => 'لا يوجد ملخص بعد للغة المختارة. اضغط على توليد لإنشاء ملخص من محتوى المستند.',
+        'metadata_kicker' => 'البيانات الوصفية',
+        'metadata_title' => 'ملاحظات الفهرس',
+        'published' => 'تاريخ النشر',
+        'tags' => 'الوسوم',
+        'size' => 'الحجم',
+        'description_kicker' => 'الوصف',
+        'description_title' => 'النص المصدر المستخدم من الذكاء الاصطناعي',
+        'no_excerpt' => 'لا يوجد مقتطف بعد للغة المختارة.',
+    ],
+][$lang];
+
 if (!$document) {
     http_response_code(404);
-    library_render_header('Document not found', 'The requested library document could not be found.', $context === 'admin' ? 'admin' : 'catalog');
+    library_render_header($pageCopy['not_found_title'], $pageCopy['not_found_description'], $context === 'admin' ? 'admin' : 'catalog');
     ?>
     <section class="panel empty-panel text-center py-5">
         <div class="empty-icon mb-3">?</div>
-        <h1 class="h4">Document not found</h1>
-        <p class="text-secondary mb-4">This item is unavailable or private.</p>
-        <a class="btn btn-dark" href="<?= $context === 'admin' ? '/admin.php' : '/index.php' ?>">Go back</a>
+        <h1 class="h4"><?= h($pageCopy['not_found_title']) ?></h1>
+        <p class="text-secondary mb-4"><?= h($pageCopy['not_found_copy']) ?></p>
+        <a class="btn btn-dark" href="<?= $context === 'admin' ? '/admin.php' : '/index.php' ?>"><?= h($pageCopy['go_back']) ?></a>
     </section>
     <?php
     library_render_footer();
@@ -38,14 +128,20 @@ if ($context !== 'admin') {
     $document = library_fetch_document((int) $document['id'], true) ?: $document;
 }
 
+$selectedTitle = library_localized_document_title($document, $lang, $pageCopy['detail_fallback']);
+$selectedTitleLang = library_text_lang($selectedTitle, $lang);
+$selectedTitleDir = library_text_dir($selectedTitle, $selectedTitleLang);
+$selectedSummary = library_localized_document_summary($document, $lang);
+$selectedDescription = library_localized_document_description($document, $lang, $pageCopy['no_excerpt']);
+
 library_render_header(
-    (string) ($document['title_en'] ?: $document['title_ar'] ?: 'Document detail'),
-    'Read a library document online, review metadata, and generate a bilingual AI summary from the document content.',
+    $selectedTitle,
+    $pageCopy['meta_description'],
     $context === 'admin' ? 'admin' : 'catalog'
 );
 ?>
 <section class="mb-4">
-    <a class="back-link" href="<?= $context === 'admin' ? '/admin.php' : '/index.php' ?>">← Back to <?= $context === 'admin' ? 'Admin Studio' : 'catalog' ?></a>
+    <a class="back-link" href="<?= $context === 'admin' ? '/admin.php' : '/index.php' ?>">← <?= h($context === 'admin' ? $pageCopy['back_to_admin'] : $pageCopy['back_to_catalog']) ?></a>
 </section>
 
 <section class="row g-4 align-items-start">
@@ -53,12 +149,7 @@ library_render_header(
         <div class="panel mb-4">
             <div class="d-flex flex-wrap justify-content-between gap-3 mb-3">
                 <div>
-                    <?php if (!empty($document['title_en'])): ?>
-                        <h1 class="display-6 mb-1"><?= h((string) $document['title_en']) ?></h1>
-                    <?php endif; ?>
-                    <?php if (!empty($document['title_ar'])): ?>
-                        <div class="lead text-secondary" dir="rtl" lang="ar"><?= h((string) $document['title_ar']) ?></div>
-                    <?php endif; ?>
+                    <h1 class="display-6 mb-1" lang="<?= h($selectedTitleLang) ?>" dir="<?= h($selectedTitleDir) ?>"><?= h($selectedTitle) ?></h1>
                 </div>
                 <div class="d-flex flex-wrap gap-2 align-content-start">
                     <span class="badge text-bg-light"><?= h(library_language_label((string) $document['document_language'])) ?></span>
@@ -68,38 +159,38 @@ library_render_header(
             </div>
 
             <div class="row g-3 small text-secondary border-top pt-3">
-                <div class="col-md-4"><strong class="text-dark d-block mb-1">Author</strong><?= h((string) ($document['author'] ?: 'Unknown author')) ?></div>
-                <div class="col-md-4"><strong class="text-dark d-block mb-1">Views</strong><?= h((string) $document['view_count']) ?></div>
-                <div class="col-md-4"><strong class="text-dark d-block mb-1">File</strong><?= h((string) ($document['file_name'] ?: 'Unavailable')) ?></div>
+                <div class="col-md-4"><strong class="text-dark d-block mb-1"><?= h($pageCopy['author']) ?></strong><?= h((string) ($document['author'] ?: $pageCopy['unknown_author'])) ?></div>
+                <div class="col-md-4"><strong class="text-dark d-block mb-1"><?= h($pageCopy['views']) ?></strong><?= h((string) $document['view_count']) ?></div>
+                <div class="col-md-4"><strong class="text-dark d-block mb-1"><?= h($pageCopy['file']) ?></strong><?= h((string) ($document['file_name'] ?: $pageCopy['unavailable'])) ?></div>
             </div>
         </div>
 
         <div class="panel reader-panel">
             <div class="d-flex justify-content-between align-items-center gap-3 mb-3">
                 <div>
-                    <div class="section-kicker">Online reader</div>
-                    <h2 class="h4 mb-0">Read in the browser</h2>
+                    <div class="section-kicker"><?= h($pageCopy['reader_kicker']) ?></div>
+                    <h2 class="h4 mb-0"><?= h($pageCopy['reader_title']) ?></h2>
                 </div>
                 <?php if (!empty($document['file_path'])): ?>
                     <?php if (library_can_preview($document)): ?>
-                        <a class="btn btn-outline-secondary btn-sm" href="/viewer.php?id=<?= $document['id'] ?><?= $context === 'admin' ? '&context=admin' : '' ?>" target="_blank">Open fullscreen</a>
+                        <a class="btn btn-outline-secondary btn-sm" href="/viewer.php?id=<?= $document['id'] ?><?= $context === 'admin' ? '&context=admin' : '' ?>" target="_blank"><?= h($pageCopy['open_fullscreen']) ?></a>
                     <?php else: ?>
-                        <a class="btn btn-outline-secondary btn-sm" href="<?= h(library_file_url((string) $document['file_path'])) ?>" target="_blank" rel="noopener">Open file</a>
+                        <a class="btn btn-outline-secondary btn-sm" href="<?= h(library_file_url((string) $document['file_path'])) ?>" target="_blank" rel="noopener"><?= h($pageCopy['open_file']) ?></a>
                     <?php endif; ?>
                 <?php endif; ?>
             </div>
 
 <?php if ($document['visibility'] === 'private' && $context !== 'admin'): ?>
             <div class="reader-lock">
-                <h3 class="h5 mb-2">Private item</h3>
-                <p class="text-secondary mb-0">This title is marked as login-required by the admin, so it stays hidden from the public reading experience.</p>
+                <h3 class="h5 mb-2"><?= h($pageCopy['private_item']) ?></h3>
+                <p class="text-secondary mb-0"><?= h($pageCopy['private_copy']) ?></p>
             </div>
 <?php elseif (library_can_preview($document)): ?>
             <!-- Flipbook Container -->
             <div id="flipbook-wrapper" data-book-direction="<?= library_get_language() === 'ar' ? 'rtl' : 'ltr' ?>" dir="ltr" style="position: relative; background: #2d3035; border-radius: 8px; overflow: hidden; height: 700px; display: flex; align-items: center; justify-content: center; direction: ltr;">
                 <div id="flipbook-loader" class="text-center text-white">
                     <div class="spinner-border mb-2" role="status"></div>
-                    <div>Loading Book...</div>
+                    <div><?= h($pageCopy['loading_book']) ?></div>
                 </div>
                 <!-- The actual book container for PageFlip -->
                 <div id="flipbook" class="shadow-lg" dir="ltr" style="display:none; direction: ltr;"></div>
@@ -107,12 +198,12 @@ library_render_header(
             
             <!-- Custom Toolbar -->
             <div id="flipbook-toolbar" class="d-flex justify-content-center align-items-center gap-3 mt-3 p-2 bg-white border rounded shadow-sm opacity-50 pe-none">
-                <button id="fb-prev" class="btn btn-outline-dark border-0 btn-lg" title="Previous Page">
+                <button id="fb-prev" class="btn btn-outline-dark border-0 btn-lg" title="<?= h($pageCopy['previous_page']) ?>">
                     <i class="bi bi-arrow-left-circle-fill"></i>
                 </button>
                 
                 <div class="text-center" style="min-width: 120px;">
-                    <span class="small text-uppercase text-secondary fw-bold" style="letter-spacing: 1px;">Page</span>
+                    <span class="small text-uppercase text-secondary fw-bold" style="letter-spacing: 1px;"><?= h($pageCopy['page']) ?></span>
                     <div class="d-flex align-items-baseline justify-content-center gap-1">
                         <span id="fb-current" class="fs-5 fw-bold font-monospace">1</span>
                         <span class="text-muted">/</span>
@@ -120,21 +211,21 @@ library_render_header(
                     </div>
                 </div>
 
-                <button id="fb-next" class="btn btn-outline-dark border-0 btn-lg" title="Next Page">
+                <button id="fb-next" class="btn btn-outline-dark border-0 btn-lg" title="<?= h($pageCopy['next_page']) ?>">
                     <i class="bi bi-arrow-right-circle-fill"></i>
                 </button>
             </div>
 
 <?php elseif (!empty($document['file_path'])): ?>
             <div class="reader-lock">
-                <h3 class="h5 mb-2">Document stored</h3>
-                <p class="text-secondary mb-3">This file type is stored successfully, but inline reading is optimized for PDF in this first slice.</p>
-                <a class="btn btn-dark" href="<?= h(library_file_url((string) $document['file_path'])) ?>" target="_blank" rel="noopener">Download / open file</a>
+                <h3 class="h5 mb-2"><?= h($pageCopy['document_stored']) ?></h3>
+                <p class="text-secondary mb-3"><?= h($pageCopy['document_stored_copy']) ?></p>
+                <a class="btn btn-dark" href="<?= h(library_file_url((string) $document['file_path'])) ?>" target="_blank" rel="noopener"><?= h($pageCopy['download_or_open']) ?></a>
             </div>
 <?php else: ?>
             <div class="reader-lock">
-                <h3 class="h5 mb-2">No file attached</h3>
-                <p class="text-secondary mb-0">Upload a file from the Admin Studio to enable reading.</p>
+                <h3 class="h5 mb-2"><?= h($pageCopy['no_file_title']) ?></h3>
+                <p class="text-secondary mb-0"><?= h($pageCopy['no_file_copy']) ?></p>
             </div>
 <?php endif; ?>
         </div>
@@ -144,46 +235,41 @@ library_render_header(
         <div class="panel mb-4" id="summary-card">
             <div class="d-flex justify-content-between align-items-start gap-3 mb-3">
                 <div>
-                    <div class="section-kicker">AI summary</div>
-                    <h2 class="h4 mb-0">Bilingual quick summary</h2>
+                    <div class="section-kicker"><?= h($pageCopy['summary_kicker']) ?></div>
+                    <h2 class="h4 mb-0"><?= h($pageCopy['summary_title']) ?></h2>
                 </div>
                 <form method="post" action="/document.php?id=<?= h((string) $document['id']) ?><?= $context === 'admin' ? '&context=admin' : '' ?>#summary-card">
                     <input type="hidden" name="action" value="generate_summary">
-                    <button class="btn btn-dark btn-sm" type="submit"><?= !empty($document['summary_text']) ? 'Regenerate' : 'Generate' ?></button>
+                    <button class="btn btn-dark btn-sm" type="submit"><?= $selectedSummary !== '' ? h($pageCopy['regenerate']) : h($pageCopy['generate']) ?></button>
                 </form>
             </div>
 
-<?php if (!empty($document['summary_text'])): ?>
-            <div class="summary-box"><?= nl2br(h((string) $document['summary_text'])) ?></div>
+<?php if ($selectedSummary !== ''): ?>
+            <div class="summary-box" lang="<?= h($lang) ?>" dir="<?= $lang === 'ar' ? 'rtl' : 'ltr' ?>"><?= nl2br(h($selectedSummary)) ?></div>
 <?php else: ?>
-            <div class="summary-box summary-box-muted">No AI summary yet. Click "Generate" to create a bilingual summary from the document content.</div>
+            <div class="summary-box summary-box-muted"><?= h($pageCopy['no_summary']) ?></div>
 <?php endif; ?>
         </div>
 
         <div class="panel mb-4">
-            <div class="section-kicker">Metadata</div>
-            <h2 class="h5 mb-3">Catalog notes</h2>
+            <div class="section-kicker"><?= h($pageCopy['metadata_kicker']) ?></div>
+            <h2 class="h5 mb-3"><?= h($pageCopy['metadata_title']) ?></h2>
             <dl class="row small gy-2 mb-0">
-                <dt class="col-4">Published</dt>
+                <dt class="col-4"><?= h($pageCopy['published']) ?></dt>
                 <dd class="col-8 mb-0"><?= h(date('M d, Y', strtotime((string) $document['created_at']))) ?></dd>
-                <dt class="col-4">Tags</dt>
+                <dt class="col-4"><?= h($pageCopy['tags']) ?></dt>
                 <dd class="col-8 mb-0"><?= h((string) ($document['tags'] ?: '—')) ?></dd>
-                <dt class="col-4">Size</dt>
+                <dt class="col-4"><?= h($pageCopy['size']) ?></dt>
                 <dd class="col-8 mb-0"><?= h((string) ($document['file_size_kb'] ?: 0)) ?> KB</dd>
             </dl>
         </div>
 
         <div class="panel">
-            <div class="section-kicker">Descriptions</div>
-            <h2 class="h5 mb-3">Source text used by AI</h2>
+            <div class="section-kicker"><?= h($pageCopy['description_kicker']) ?></div>
+            <h2 class="h5 mb-3"><?= h($pageCopy['description_title']) ?></h2>
             <div class="description-stack">
                 <div>
-                    <div class="small text-uppercase text-secondary mb-2">English</div>
-                    <p class="mb-0 text-secondary"><?= h((string) ($document['description_en'] ?: 'No English excerpt yet.')) ?></p>
-                </div>
-                <div>
-                    <div class="small text-uppercase text-secondary mb-2">العربية</div>
-                    <p class="mb-0 text-secondary" dir="rtl" lang="ar"><?= h((string) ($document['description_ar'] ?: 'لا يوجد مقتطف عربي حتى الآن.')) ?></p>
+                    <p class="mb-0 text-secondary" lang="<?= h($lang) ?>" dir="<?= $lang === 'ar' ? 'rtl' : 'ltr' ?>"><?= h($selectedDescription) ?></p>
                 </div>
             </div>
         </div>
diff --git a/includes/admin_layout.php b/includes/admin_layout.php
index 8fe46a5..d08e90e 100644
--- a/includes/admin_layout.php
+++ b/includes/admin_layout.php
@@ -117,12 +117,12 @@ function admin_render_footer(): void {
         const text = source.value.trim();
 
         if (!text) {
-            alert('Please enter text to translate.');
+            alert(<?= json_encode(library_trans('translation_enter_text')) ?>);
             return;
         }
 
         const originalPlaceholder = target.placeholder;
-        target.placeholder = 'Translating...';
+        target.placeholder = <?= json_encode(library_trans('translating')) ?>;
         const originalOpacity = target.style.opacity;
         target.style.opacity = '0.7';
 
@@ -133,17 +133,17 @@ function admin_render_footer(): void {
                 body: JSON.stringify({ text: text, target_lang: targetLang })
             });
 
-            if (!response.ok) throw new Error('Translation failed');
+            if (!response.ok) throw new Error(<?= json_encode(library_trans('translation_failed')) ?>);
 
             const data = await response.json();
             if (data.translation) {
                 target.value = data.translation;
             } else if (data.error) {
-                alert('Translation error: ' + data.error);
+                alert(<?= json_encode(library_trans('translation_error_prefix')) ?> + ' ' + data.error);
             }
         } catch (e) {
             console.error(e);
-            alert('Translation failed. Please try again.');
+            alert(<?= json_encode(library_trans('translation_failed')) ?>);
         } finally {
             target.placeholder = originalPlaceholder;
             target.style.opacity = originalOpacity;
diff --git a/includes/layout.php b/includes/layout.php
index b8ef9a8..4ddec47 100644
--- a/includes/layout.php
+++ b/includes/layout.php
@@ -78,7 +78,7 @@ function library_render_header(string $pageTitle, string $pageDescription, strin
                     <li class="nav-item border-start border-secondary mx-2 d-none d-lg-block" style="opacity: 0.3; height: 24px;"></li>
                     
                     <li class="nav-item">
-                        <a class="nav-link fw-bold text-primary" href="<?= h($switchUrl) ?>">
+                        <a class="btn btn-sm btn-outline-dark topbar-lang-switch" href="<?= h($switchUrl) ?>" lang="<?= h($targetLang) ?>" dir="<?= $targetLang === 'ar' ? 'rtl' : 'ltr' ?>">
                             <?= h($switchLabel) ?>
                         </a>
                     </li>
diff --git a/includes/library.php b/includes/library.php
index 0945e31..c7f701c 100644
--- a/includes/library.php
+++ b/includes/library.php
@@ -69,6 +69,7 @@ function library_trans(string $key, ?string $lang = null): string
             'return_to_site' => 'Return to Site',
             'total_documents' => 'Total Documents',
             'public_titles' => 'Public Titles',
+            'private_titles' => 'Private Titles',
             'total_downloads' => 'Total Downloads',
             'recent_documents' => 'Recent Documents',
             'title_author' => 'Title / Author',
@@ -128,7 +129,41 @@ function library_trans(string $key, ?string $lang = null): string
             'previous' => 'Previous',
             'next' => 'Next',
             'showing_page' => 'Showing page',
-            'of' => 'of'
+            'of' => 'of',
+            'no_documents_found' => 'No documents found.',
+            'submission_error' => 'Submission Error',
+            'current_cover' => 'Current Cover:',
+            'visibility_public' => 'Public',
+            'visibility_private' => 'Private',
+            'unknown' => 'Unknown',
+            'translation_to_arabic' => 'Translate to Arabic',
+            'translation_to_english' => 'Translate to English',
+            'translation_enter_text' => 'Please enter text to translate.',
+            'translating' => 'Translating...',
+            'translation_failed' => 'Translation failed. Please try again.',
+            'translation_error_prefix' => 'Translation error:',
+            'category_name_required' => 'Both English and Arabic names are required for Category.',
+            'category_update_required' => 'ID, English name, and Arabic name are required.',
+            'invalid_category_id' => 'Invalid Category ID.',
+            'category_created_success' => 'Category created successfully.',
+            'category_updated_success' => 'Category updated successfully.',
+            'category_deleted_success' => 'Category deleted successfully.',
+            'subcategory_name_required' => 'Category, English name, and Arabic name are required.',
+            'subcategory_update_required' => 'ID, Category, English name, and Arabic name are required.',
+            'invalid_subcategory_id' => 'Invalid Subcategory ID.',
+            'subcategory_created_success' => 'Subcategory created successfully.',
+            'subcategory_updated_success' => 'Subcategory updated successfully.',
+            'subcategory_deleted_success' => 'Subcategory deleted successfully.',
+            'type_name_required' => 'Both English and Arabic names are required for Type.',
+            'type_update_required' => 'ID, English name, and Arabic name are required.',
+            'invalid_type_id' => 'Invalid Type ID.',
+            'type_created_success' => 'Type created successfully.',
+            'type_updated_success' => 'Type updated successfully.',
+            'type_deleted_success' => 'Type deleted successfully.',
+            'invalid_document_id' => 'Invalid Document ID.',
+            'document_created_success' => 'Document created successfully.',
+            'document_updated_success' => 'Document updated successfully.',
+            'document_deleted_success' => 'Document deleted successfully.'
         ],
         'ar' => [
             'catalog' => 'الفهرس',
@@ -145,12 +180,13 @@ function library_trans(string $key, ?string $lang = null): string
             'admin_panel' => 'لوحة التحكم',
             'dashboard' => 'لوحة القيادة',
             'material_entry' => 'إدخال المواد',
-            'categories' => 'الفئات',
-            'subcategories' => 'الفئات الفرعية',
+            'categories' => 'التصنيف',
+            'subcategories' => 'التصنيف الفرعي',
             'types' => 'الأنواع',
             'return_to_site' => 'العودة للموقع',
             'total_documents' => 'إجمالي المستندات',
             'public_titles' => 'العناوين العامة',
+            'private_titles' => 'العناوين الخاصة',
             'total_downloads' => 'إجمالي التنزيلات',
             'recent_documents' => 'أحدث المستندات',
             'title_author' => 'العنوان / المؤلف',
@@ -171,7 +207,7 @@ function library_trans(string $key, ?string $lang = null): string
             'description_en' => 'الوصف (إنجليزي)',
             'description_ar' => 'الوصف (عربي)',
             'confirm_delete' => 'هل أنت متأكد من حذف هذا العنصر؟',
-            'manage_categories_desc' => 'إدارة فئات المستندات.',
+            'manage_categories_desc' => 'إدارة التصنيف للمستندات',
             'add_new_category' => 'إضافة فئة جديدة',
             'search_placeholder' => 'بحث...',
             'clear' => 'مسح',
@@ -200,7 +236,7 @@ function library_trans(string $key, ?string $lang = null): string
             'required_new_docs' => 'مطلوب للمستندات الجديدة.',
             'leave_empty_keep' => 'اتركه فارغاً للاحتفاظ بالملف الحالي.',
             'save_changes' => 'حفظ التغييرات',
-            'manage_subcategories_desc' => 'إدارة الفئات الفرعية للمستندات.',
+            'manage_subcategories_desc' => 'إدارة التصنيف الفرعي للمستندات.',
             'add_new_subcategory' => 'إضافة فئة فرعية جديدة',
             'no_subcategories_found' => 'لم يتم العثور على فئات فرعية.',
             'category' => 'الفئة',
@@ -210,7 +246,41 @@ function library_trans(string $key, ?string $lang = null): string
             'previous' => 'السابق',
             'next' => 'التالي',
             'showing_page' => 'عرض صفحة',
-            'of' => 'من'
+            'of' => 'من',
+            'no_documents_found' => 'لم يتم العثور على مستندات.',
+            'submission_error' => 'خطأ في الإرسال',
+            'current_cover' => 'الغلاف الحالي:',
+            'visibility_public' => 'عام',
+            'visibility_private' => 'خاص',
+            'unknown' => 'غير معروف',
+            'translation_to_arabic' => 'ترجمة إلى العربية',
+            'translation_to_english' => 'ترجمة إلى الإنجليزية',
+            'translation_enter_text' => 'يرجى إدخال نص للترجمة.',
+            'translating' => 'جارٍ الترجمة...',
+            'translation_failed' => 'فشلت الترجمة. يرجى المحاولة مرة أخرى.',
+            'translation_error_prefix' => 'خطأ في الترجمة:',
+            'category_name_required' => 'اسما التصنيف بالإنجليزية والعربية مطلوبان.',
+            'category_update_required' => 'المعرف واسم التصنيف بالإنجليزية والعربية مطلوبة.',
+            'invalid_category_id' => 'معرف التصنيف غير صالح.',
+            'category_created_success' => 'تم إنشاء التصنيف بنجاح.',
+            'category_updated_success' => 'تم تحديث التصنيف بنجاح.',
+            'category_deleted_success' => 'تم حذف التصنيف بنجاح.',
+            'subcategory_name_required' => 'التصنيف واسم التصنيف الفرعي بالإنجليزية والعربية مطلوبة.',
+            'subcategory_update_required' => 'المعرف والتصنيف واسم التصنيف الفرعي بالإنجليزية والعربية مطلوبة.',
+            'invalid_subcategory_id' => 'معرف التصنيف الفرعي غير صالح.',
+            'subcategory_created_success' => 'تم إنشاء التصنيف الفرعي بنجاح.',
+            'subcategory_updated_success' => 'تم تحديث التصنيف الفرعي بنجاح.',
+            'subcategory_deleted_success' => 'تم حذف التصنيف الفرعي بنجاح.',
+            'type_name_required' => 'اسما النوع بالإنجليزية والعربية مطلوبان.',
+            'type_update_required' => 'المعرف واسم النوع بالإنجليزية والعربية مطلوبة.',
+            'invalid_type_id' => 'معرف النوع غير صالح.',
+            'type_created_success' => 'تم إنشاء النوع بنجاح.',
+            'type_updated_success' => 'تم تحديث النوع بنجاح.',
+            'type_deleted_success' => 'تم حذف النوع بنجاح.',
+            'invalid_document_id' => 'معرف المستند غير صالح.',
+            'document_created_success' => 'تم إنشاء المستند بنجاح.',
+            'document_updated_success' => 'تم تحديث المستند بنجاح.',
+            'document_deleted_success' => 'تم حذف المستند بنجاح.'
         ]
     ];
 
@@ -341,31 +411,110 @@ function library_old(string $key, string $default = ''): string
     return isset($_POST[$key]) ? trim((string) $_POST[$key]) : $default;
 }
 
+function library_localized_value(?string $english, ?string $arabic, ?string $lang = null, string $fallback = ''): string
+{
+    $lang = $lang ?? library_get_language();
+    $primary = trim((string) ($lang === 'ar' ? $arabic : $english));
+    $secondary = trim((string) ($lang === 'ar' ? $english : $arabic));
+
+    if ($primary !== '') {
+        return $primary;
+    }
+
+    if ($secondary !== '') {
+        return $secondary;
+    }
+
+    return $fallback;
+}
+
+function library_localized_document_title(array $document, ?string $lang = null, string $fallback = 'Untitled'): string
+{
+    return library_localized_value(
+        $document['title_en'] ?? null,
+        $document['title_ar'] ?? null,
+        $lang,
+        $fallback
+    );
+}
+
+function library_localized_document_description(array $document, ?string $lang = null, string $fallback = ''): string
+{
+    return library_localized_value(
+        $document['description_en'] ?? null,
+        $document['description_ar'] ?? null,
+        $lang,
+        $fallback
+    );
+}
+
+function library_localized_document_summary(array $document, ?string $lang = null, string $fallback = ''): string
+{
+    $summary = library_localized_value(
+        $document['summary_en'] ?? null,
+        $document['summary_ar'] ?? null,
+        $lang,
+        ''
+    );
+
+    if ($summary !== '') {
+        return $summary;
+    }
+
+    $combined = trim((string) ($document['summary_text'] ?? ''));
+    return $combined !== '' ? $combined : $fallback;
+}
+
 function library_document_type_label(string $type): string
 {
+    $lang = library_get_language();
     $map = [
-        'pdf' => 'PDF reader',
-        'txt' => 'Text note',
-        'doc' => 'Word document',
-        'docx' => 'Word document',
-        'ppt' => 'PowerPoint',
-        'pptx' => 'PowerPoint',
+        'en' => [
+            'pdf' => 'PDF reader',
+            'txt' => 'Text note',
+            'doc' => 'Word document',
+            'docx' => 'Word document',
+            'ppt' => 'PowerPoint',
+            'pptx' => 'PowerPoint',
+        ],
+        'ar' => [
+            'pdf' => 'قارئ PDF',
+            'txt' => 'ملاحظة نصية',
+            'doc' => 'مستند Word',
+            'docx' => 'مستند Word',
+            'ppt' => 'عرض PowerPoint',
+            'pptx' => 'عرض PowerPoint',
+        ],
     ];
-    return $map[strtolower($type)] ?? strtoupper($type);
+
+    return $map[$lang][strtolower($type)] ?? strtoupper($type);
 }
 
 function library_language_label(string $lang): string
 {
+    $uiLang = library_get_language();
     $map = [
-        'en' => 'English',
-        'ar' => 'Arabic',
-        'bilingual' => 'Bilingual',
+        'en' => [
+            'en' => 'English',
+            'ar' => 'Arabic',
+            'bilingual' => 'Bilingual',
+        ],
+        'ar' => [
+            'en' => 'الإنجليزية',
+            'ar' => 'العربية',
+            'bilingual' => 'ثنائي اللغة',
+        ],
     ];
-    return $map[$lang] ?? 'Unknown';
+
+    return $map[$uiLang][$lang] ?? ($uiLang === 'ar' ? 'غير معروف' : 'Unknown');
 }
 
 function library_visibility_label(string $visibility): string
 {
+    if (library_get_language() === 'ar') {
+        return $visibility === 'private' ? 'خاص / يتطلب تسجيل الدخول' : 'عام';
+    }
+
     return $visibility === 'private' ? 'Private / login' : 'Public';
 }
 
diff --git a/index.php b/index.php
index e4b8fc0..32d80c8 100644
--- a/index.php
+++ b/index.php
@@ -6,66 +6,176 @@ require_once __DIR__ . '/includes/layout.php';
 
 library_bootstrap();
 
+$lang = library_get_language();
 $query = trim((string) ($_GET['q'] ?? ''));
 $language = trim((string) ($_GET['language'] ?? ''));
 
+$pageCopy = [
+    'en' => [
+        'meta_title' => 'Digital Catalog',
+        'meta_description' => 'Browse the public digital catalog, switch the interface language from the top bar, and open documents in the browser.',
+        'hero_eyebrow' => 'Electronic library · one language per view',
+        'hero_title' => 'A cleaner catalog with a top-bar language switch.',
+        'hero_copy' => 'The public library now stays in one interface language at a time. Use the switch in the top bar to move between English and Arabic while keeping the same page.',
+        'browse_catalog' => 'Browse catalog',
+        'add_documents' => 'Add documents',
+        'snapshot_kicker' => 'Live shelf snapshot',
+        'snapshot_title' => 'What this delivery includes',
+        'snapshot_badge' => 'Updated UI',
+        'public_titles' => 'Public titles',
+        'private_titles' => 'Private titles',
+        'ai_summaries' => 'AI summaries',
+        'snapshot_item_1' => 'Single-language public pages with a top-bar switch',
+        'snapshot_item_2' => 'Catalog filters for keyword and content language',
+        'snapshot_item_3' => 'Document pages with localized title, summary, and description',
+        'discovery_kicker' => 'Public discovery',
+        'discovery_title' => 'Search the live collection',
+        'keyword' => 'Keyword',
+        'keyword_placeholder' => 'Title, author, tag, or excerpt',
+        'language_filter' => 'Content language',
+        'all_shelves' => 'All shelves',
+        'filter' => 'Filter',
+        'rules_kicker' => 'Visibility rules',
+        'rules_title' => 'Admin-controlled access',
+        'rules_copy' => 'Public items appear in this catalog immediately. Private items stay off the public shelf and remain available only from the admin workspace.',
+        'rules_link' => 'Review publishing controls',
+        'catalog_kicker' => 'Catalog',
+        'catalog_title' => 'Available public titles',
+        'result_singular' => 'result',
+        'result_plural' => 'results',
+        'empty_title' => 'No public documents yet',
+        'empty_copy' => 'Upload your first Arabic or English document from the Admin Studio to turn this into a browsable library.',
+        'open_admin' => 'Open Admin Studio',
+        'no_cover' => 'No cover',
+        'untitled' => 'Untitled document',
+        'cover_alt' => 'Cover image for',
+        'author' => 'Author',
+        'views' => 'Views',
+        'tags' => 'Tags',
+        'author_fallback' => 'Not set',
+        'open_reader' => 'Open reader →',
+        'workflow_kicker' => 'Workflow',
+        'workflow_title' => 'Thin slice, end to end',
+        'workflow_item_1' => 'Admin uploads a document and chooses public or private visibility.',
+        'workflow_item_2' => 'Readers discover public titles from the catalog and open the detail page.',
+        'workflow_item_3' => 'Summaries and descriptions follow the selected interface language.',
+        'recent_kicker' => 'Recently added',
+        'recent_title' => 'Latest public titles',
+        'manage_shelf' => 'Manage shelf',
+        'unknown_author' => 'Unknown author',
+    ],
+    'ar' => [
+        'meta_title' => 'الفهرس الرقمي',
+        'meta_description' => 'تصفح الفهرس الرقمي العام، وبدّل لغة الواجهة من الشريط العلوي، وافتح المستندات داخل المتصفح.',
+        'hero_eyebrow' => 'مكتبة إلكترونية · لغة واحدة لكل عرض',
+        'hero_title' => 'فهرس أوضح مع مفتاح تبديل اللغة في الشريط العلوي.',
+        'hero_copy' => 'تعرض المكتبة العامة الآن لغة واجهة واحدة في كل مرة. استخدم المفتاح في الشريط العلوي للتبديل بين العربية والإنجليزية مع البقاء في الصفحة نفسها.',
+        'browse_catalog' => 'تصفح الفهرس',
+        'add_documents' => 'إضافة مستندات',
+        'snapshot_kicker' => 'نظرة مباشرة على الرف',
+        'snapshot_title' => 'ما الذي يتضمنه هذا التحديث',
+        'snapshot_badge' => 'واجهة محدثة',
+        'public_titles' => 'العناوين العامة',
+        'private_titles' => 'العناوين الخاصة',
+        'ai_summaries' => 'ملخصات الذكاء الاصطناعي',
+        'snapshot_item_1' => 'صفحات عامة بلغة واحدة مع مفتاح تبديل في الشريط العلوي',
+        'snapshot_item_2' => 'مرشحات للفهرس حسب الكلمة المفتاحية ولغة المحتوى',
+        'snapshot_item_3' => 'صفحات مستندات بعنوان وملخص ووصف حسب اللغة المختارة',
+        'discovery_kicker' => 'الاكتشاف العام',
+        'discovery_title' => 'ابحث في المجموعة المباشرة',
+        'keyword' => 'الكلمة المفتاحية',
+        'keyword_placeholder' => 'العنوان أو المؤلف أو الوسوم أو المقتطف',
+        'language_filter' => 'لغة المحتوى',
+        'all_shelves' => 'كل الرفوف',
+        'filter' => 'تصفية',
+        'rules_kicker' => 'قواعد الظهور',
+        'rules_title' => 'وصول يتحكم به المشرف',
+        'rules_copy' => 'تظهر العناصر العامة في هذا الفهرس فوراً، بينما تبقى العناصر الخاصة خارج الرف العام ومتاحة فقط من مساحة الإدارة.',
+        'rules_link' => 'مراجعة إعدادات النشر',
+        'catalog_kicker' => 'الفهرس',
+        'catalog_title' => 'العناوين العامة المتاحة',
+        'result_singular' => 'نتيجة',
+        'result_plural' => 'نتائج',
+        'empty_title' => 'لا توجد مستندات عامة بعد',
+        'empty_copy' => 'ارفع أول مستند عربي أو إنجليزي من استوديو الإدارة لتحويل هذا القسم إلى مكتبة قابلة للتصفح.',
+        'open_admin' => 'فتح استوديو الإدارة',
+        'no_cover' => 'بلا غلاف',
+        'untitled' => 'مستند بدون عنوان',
+        'cover_alt' => 'صورة غلاف لـ',
+        'author' => 'المؤلف',
+        'views' => 'المشاهدات',
+        'tags' => 'الوسوم',
+        'author_fallback' => 'غير محدد',
+        'open_reader' => 'فتح القارئ ←',
+        'workflow_kicker' => 'سير العمل',
+        'workflow_title' => 'مسار كامل ومختصر',
+        'workflow_item_1' => 'يرفع المشرف مستنداً ويحدد ما إذا كان عاماً أو خاصاً.',
+        'workflow_item_2' => 'يكتشف القراء العناوين العامة من الفهرس ويفتحون صفحة التفاصيل.',
+        'workflow_item_3' => 'تتبع الملخصات والأوصاف لغة الواجهة المختارة.',
+        'recent_kicker' => 'أضيف مؤخراً',
+        'recent_title' => 'أحدث العناوين العامة',
+        'manage_shelf' => 'إدارة الرف',
+        'unknown_author' => 'مؤلف غير معروف',
+    ],
+][$lang];
+
 // Pagination Logic
-$page = isset($_GET['page']) ? max(1, (int)$_GET['page']) : 1;
-$limit = 12; // Grid layout 3x4
+$page = isset($_GET['page']) ? max(1, (int) $_GET['page']) : 1;
+$limit = 12;
 $offset = ($page - 1) * $limit;
 
 $result = library_fetch_documents_paginated(true, ['q' => $query, 'language' => $language], $limit, $offset);
 $documents = $result['data'];
 $totalDocuments = $result['total'];
-$totalPages = (int)ceil($totalDocuments / $limit);
+$totalPages = (int) ceil($totalDocuments / $limit);
 
 $metrics = library_catalog_metrics();
 $recentDocuments = library_recent_documents(3, true);
 
 library_render_header(
-    'Digital Catalog',
-    'Browse a polished Arabic and English e-library with online reading, public/private publishing controls, and AI-ready summaries.',
+    $pageCopy['meta_title'],
+    $pageCopy['meta_description'],
     'catalog'
 );
 ?>
 <section class="hero-surface mb-4 mb-lg-5">
     <div class="row g-4 align-items-center">
         <div class="col-lg-7">
-            <span class="eyebrow">Electronic library · Arabic + English</span>
-            <h1 class="display-6 mb-3">A focused e-library for bilingual reading, controlled publishing, and AI-ready summaries.</h1>
-            <p class="lead text-secondary mb-4">Readers can search the public shelf, open PDFs in-browser, and review concise AI summaries. Your content team can publish titles as public or private from one admin studio.</p>
+            <span class="eyebrow"><?= h($pageCopy['hero_eyebrow']) ?></span>
+            <h1 class="display-6 mb-3"><?= h($pageCopy['hero_title']) ?></h1>
+            <p class="lead text-secondary mb-4"><?= h($pageCopy['hero_copy']) ?></p>
             <div class="d-flex flex-wrap gap-2">
-                <a class="btn btn-dark" href="#catalog-grid">Browse catalog</a>
-                <a class="btn btn-outline-secondary" href="/admin.php">Add documents</a>
+                <a class="btn btn-dark" href="#catalog-grid"><?= h($pageCopy['browse_catalog']) ?></a>
+                <a class="btn btn-outline-secondary" href="/admin.php"><?= h($pageCopy['add_documents']) ?></a>
             </div>
         </div>
         <div class="col-lg-5">
             <div class="panel h-100">
                 <div class="d-flex justify-content-between align-items-start gap-3 mb-4">
                     <div>
-                        <div class="section-kicker">Live shelf snapshot</div>
-                        <h2 class="h5 mb-1">What this first delivery includes</h2>
+                        <div class="section-kicker"><?= h($pageCopy['snapshot_kicker']) ?></div>
+                        <h2 class="h5 mb-1"><?= h($pageCopy['snapshot_title']) ?></h2>
                     </div>
-                    <span class="badge text-bg-light">MVP slice</span>
+                    <span class="badge text-bg-light"><?= h($pageCopy['snapshot_badge']) ?></span>
                 </div>
                 <div class="metric-grid">
                     <article class="metric-card">
                         <span class="metric-value"><?= h((string) $metrics['public_count']) ?></span>
-                        <span class="metric-label">Public titles</span>
+                        <span class="metric-label"><?= h($pageCopy['public_titles']) ?></span>
                     </article>
                     <article class="metric-card">
                         <span class="metric-value"><?= h((string) $metrics['private_count']) ?></span>
-                        <span class="metric-label">Private titles</span>
+                        <span class="metric-label"><?= h($pageCopy['private_titles']) ?></span>
                     </article>
                     <article class="metric-card">
                         <span class="metric-value"><?= h((string) $metrics['summarized_count']) ?></span>
-                        <span class="metric-label">AI summaries</span>
+                        <span class="metric-label"><?= h($pageCopy['ai_summaries']) ?></span>
                     </article>
                 </div>
                 <ul class="list-unstyled mb-0 mt-4 compact-list">
-                    <li>Public catalog with search and language filters</li>
-                    <li>Admin upload workflow with visibility control</li>
-                    <li>Document detail view with embedded PDF reader</li>
+                    <li><?= h($pageCopy['snapshot_item_1']) ?></li>
+                    <li><?= h($pageCopy['snapshot_item_2']) ?></li>
+                    <li><?= h($pageCopy['snapshot_item_3']) ?></li>
                 </ul>
             </div>
         </div>
@@ -75,145 +185,144 @@ library_render_header(
 <section class="row g-4 mb-4 mb-lg-5">
     <div class="col-lg-8">
         <div class="panel h-100">
-            <div class="section-kicker">Public discovery</div>
-            <h2 class="h4 mb-3">Search the live collection</h2>
+            <div class="section-kicker"><?= h($pageCopy['discovery_kicker']) ?></div>
+            <h2 class="h4 mb-3"><?= h($pageCopy['discovery_title']) ?></h2>
             <form class="row g-3 align-items-end" method="get" action="/index.php">
                 <div class="col-md-7">
-                    <label class="form-label" for="q">Keyword</label>
-                    <input class="form-control" id="q" name="q" type="search" value="<?= h($query) ?>" placeholder="Title, author, tag, or excerpt">
+                    <label class="form-label" for="q"><?= h($pageCopy['keyword']) ?></label>
+                    <input class="form-control" id="q" name="q" type="search" value="<?= h($query) ?>" placeholder="<?= h($pageCopy['keyword_placeholder']) ?>">
                 </div>
                 <div class="col-md-3">
-                    <label class="form-label" for="language">Language</label>
+                    <label class="form-label" for="language"><?= h($pageCopy['language_filter']) ?></label>
                     <select class="form-select" id="language" name="language">
-                        <option value="">All shelves</option>
-                        <option value="en" <?= $language === 'en' ? 'selected' : '' ?>>English</option>
-                        <option value="ar" <?= $language === 'ar' ? 'selected' : '' ?>>Arabic</option>
-                        <option value="bilingual" <?= $language === 'bilingual' ? 'selected' : '' ?>>Bilingual</option>
+                        <option value=""><?= h($pageCopy['all_shelves']) ?></option>
+                        <option value="en" <?= $language === 'en' ? 'selected' : '' ?>><?= h(library_language_label('en')) ?></option>
+                        <option value="ar" <?= $language === 'ar' ? 'selected' : '' ?>><?= h(library_language_label('ar')) ?></option>
+                        <option value="bilingual" <?= $language === 'bilingual' ? 'selected' : '' ?>><?= h(library_language_label('bilingual')) ?></option>
                     </select>
                 </div>
                 <div class="col-md-2 d-grid">
-                    <button class="btn btn-dark" type="submit">Filter</button>
+                    <button class="btn btn-dark" type="submit"><?= h($pageCopy['filter']) ?></button>
                 </div>
             </form>
         </div>
     </div>
     <div class="col-lg-4">
         <div class="panel h-100">
-            <div class="section-kicker">Visibility rules</div>
-            <h2 class="h5 mb-3">Admin-controlled access</h2>
-            <p class="text-secondary mb-3">Public items appear in this catalog immediately. Private items stay out of the public shelf and are marked for member login in the admin workspace.</p>
-            <a class="link-arrow" href="/admin.php">Review publishing controls</a>
+            <div class="section-kicker"><?= h($pageCopy['rules_kicker']) ?></div>
+            <h2 class="h5 mb-3"><?= h($pageCopy['rules_title']) ?></h2>
+            <p class="text-secondary mb-3"><?= h($pageCopy['rules_copy']) ?></p>
+            <a class="link-arrow" href="/admin.php"><?= h($pageCopy['rules_link']) ?></a>
         </div>
     </div>
 </section>
 
 <section class="mb-5" id="catalog-grid">
-    <div class="d-flex justify-content-between align-items-center mb-3">
+    <div class="d-flex justify-content-between align-items-center mb-3 gap-3 flex-wrap">
         <div>
-            <div class="section-kicker">Catalog</div>
-            <h2 class="h3 mb-0">Available public titles</h2>
+            <div class="section-kicker"><?= h($pageCopy['catalog_kicker']) ?></div>
+            <h2 class="h3 mb-0"><?= h($pageCopy['catalog_title']) ?></h2>
         </div>
-        <span class="text-secondary small"><?= h((string) $totalDocuments) ?> result<?= $totalDocuments === 1 ? '' : 's' ?></span>
+        <span class="text-secondary small"><?= h((string) $totalDocuments) ?> <?= h($totalDocuments === 1 ? $pageCopy['result_singular'] : $pageCopy['result_plural']) ?></span>
     </div>
 
 <?php if (!$documents): ?>
     <div class="panel empty-panel text-center py-5">
         <div class="empty-icon mb-3">⌘</div>
-        <h3 class="h5">No public documents yet</h3>
-        <p class="text-secondary mb-4">Upload your first Arabic or English PDF from the Admin Studio to turn this into a browsable library.</p>
-        <a class="btn btn-dark" href="/admin.php">Open Admin Studio</a>
+        <h3 class="h5"><?= h($pageCopy['empty_title']) ?></h3>
+        <p class="text-secondary mb-4"><?= h($pageCopy['empty_copy']) ?></p>
+        <a class="btn btn-dark" href="/admin.php"><?= h($pageCopy['open_admin']) ?></a>
     </div>
 <?php else: ?>
-    <div class="row g-4">
+    <div class="row row-cols-1 row-cols-md-2 row-cols-lg-3 g-4">
 <?php foreach ($documents as $document): ?>
 <?php
-    $cardSummary = (string) ($document['summary_text'] ?: ($document['description_en'] ?: $document['description_ar'] ?: 'No summary yet.'));
-    $cardSummaryLang = library_text_lang(
-        $cardSummary,
-        !empty($document['description_ar']) && empty($document['summary_text']) && empty($document['description_en']) ? 'ar' : 'en'
-    );
-    $cardSummaryDir = library_text_dir($cardSummary, $cardSummaryLang);
+    $cardTitle = library_localized_document_title($document, $lang, $pageCopy['untitled']);
+    $cardTitleLang = library_text_lang($cardTitle, $lang);
+    $cardTitleDir = library_text_dir($cardTitle, $cardTitleLang);
 ?>
-        <div class="col-md-6 col-xl-4">
-            <article class="panel h-100 d-flex flex-column">
-                <div class="d-flex justify-content-between align-items-start gap-3 mb-3">
-                    <div class="d-flex flex-wrap gap-2">
-                        <span class="badge text-bg-light"><?= h(library_language_label((string) $document['document_language'])) ?></span>
-                        <span class="badge text-bg-light"><?= h(library_document_type_label((string) $document['document_type'])) ?></span>
+        <div class="col">
+            <article class="panel catalog-card h-100 position-relative">
+                <div class="catalog-card-media">
+                    <?php if (!empty($document['cover_image_path'])): ?>
+                        <img
+                            src="/<?= h((string) $document['cover_image_path']) ?>"
+                            alt="<?= h($pageCopy['cover_alt'] . ' ' . $cardTitle) ?>"
+                            class="catalog-card-cover"
+                            width="128"
+                            height="176"
+                        >
+                    <?php else: ?>
+                        <div class="catalog-card-cover catalog-card-cover-placeholder" aria-hidden="true">
+                            <span><?= h($pageCopy['no_cover']) ?></span>
+                        </div>
+                    <?php endif; ?>
+                </div>
+
+                <div class="catalog-card-body">
+                    <div class="d-flex flex-wrap justify-content-between align-items-start gap-3 mb-2">
+                        <div class="min-w-0">
+                            <h3 class="h5 mb-1 catalog-card-title" lang="<?= h($cardTitleLang) ?>" dir="<?= h($cardTitleDir) ?>"><?= h($cardTitle) ?></h3>
+                        </div>
+                    </div>
+
+                    <div class="catalog-card-meta small text-secondary">
+                        <div><span class="catalog-card-label"><?= h($pageCopy['author']) ?></span><span><?= h((string) ($document['author'] ?: $pageCopy['author_fallback'])) ?></span></div>
+                        <div><span class="catalog-card-label"><?= h($pageCopy['views']) ?></span><span><?= h((string) $document['view_count']) ?></span></div>
+                        <div><span class="catalog-card-label"><?= h($pageCopy['tags']) ?></span><span><?= h((string) ($document['tags'] ?: '—')) ?></span></div>
+                    </div>
+
+                    <div class="mt-3">
+                        <a class="link-arrow stretched-link" href="/document.php?id=<?= h((string) $document['id']) ?>"><?= h($pageCopy['open_reader']) ?></a>
                     </div>
-                    <?php if (!empty($document['is_featured'])): ?>
-                        <span class="badge text-bg-dark">Featured</span>
-                    <?php endif; ?>
-                </div>
-                <div class="mb-3">
-                    <?php if (!empty($document['title_en'])): ?>
-                        <h3 class="h5 mb-1"><?= h((string) $document['title_en']) ?></h3>
-                    <?php endif; ?>
-                    <?php if (!empty($document['title_ar'])): ?>
-                        <div class="text-secondary" dir="rtl" lang="ar"><?= h((string) $document['title_ar']) ?></div>
-                    <?php endif; ?>
-                </div>
-                <dl class="row small text-secondary mb-3 gx-2 gy-1">
-                    <dt class="col-4">Author</dt>
-                    <dd class="col-8 mb-0"><?= h((string) ($document['author'] ?: 'Not set')) ?></dd>
-                    <dt class="col-4">Views</dt>
-                    <dd class="col-8 mb-0"><?= h((string) $document['view_count']) ?></dd>
-                    <dt class="col-4">Tags</dt>
-                    <dd class="col-8 mb-0"><?= h((string) ($document['tags'] ?: '—')) ?></dd>
-                </dl>
-                <p class="text-secondary flex-grow-1" lang="<?= h($cardSummaryLang) ?>" dir="<?= h($cardSummaryDir) ?>"><?= h($cardSummary) ?></p>
-                <div class="d-flex gap-2 mt-3">
-                    <a class="btn btn-dark btn-sm" href="/document.php?id=<?= h((string) $document['id']) ?>">Open reader</a>
-                    <a class="btn btn-outline-secondary btn-sm" href="/document.php?id=<?= h((string) $document['id']) ?>#summary-card">View summary</a>
                 </div>
             </article>
         </div>
 <?php endforeach; ?>
     </div>
-    
-    <!-- Pagination -->
+
     <?php if ($totalPages > 1): ?>
         <div class="mt-5">
             <?php library_render_pagination($page, $totalPages, '/index.php'); ?>
         </div>
     <?php endif; ?>
-    
+
 <?php endif; ?>
 </section>
 
 <section class="row g-4">
     <div class="col-lg-4">
         <div class="panel h-100">
-            <div class="section-kicker">Workflow</div>
-            <h2 class="h5 mb-3">Thin slice, end to end</h2>
+            <div class="section-kicker"><?= h($pageCopy['workflow_kicker']) ?></div>
+            <h2 class="h5 mb-3"><?= h($pageCopy['workflow_title']) ?></h2>
             <ol class="compact-list-numbered mb-0 text-secondary">
-                <li>Admin uploads a document and chooses public or private visibility.</li>
-                <li>Readers discover public titles from the catalog and open the detail page.</li>
-                <li>AI summaries can be generated from the saved excerpt for faster review.</li>
+                <li><?= h($pageCopy['workflow_item_1']) ?></li>
+                <li><?= h($pageCopy['workflow_item_2']) ?></li>
+                <li><?= h($pageCopy['workflow_item_3']) ?></li>
             </ol>
         </div>
     </div>
     <div class="col-lg-8">
         <div class="panel h-100">
-            <div class="d-flex justify-content-between align-items-center mb-3">
+            <div class="d-flex justify-content-between align-items-center mb-3 gap-3 flex-wrap">
                 <div>
-                    <div class="section-kicker">Recently added</div>
-                    <h2 class="h5 mb-0">Latest public titles</h2>
+                    <div class="section-kicker"><?= h($pageCopy['recent_kicker']) ?></div>
+                    <h2 class="h5 mb-0"><?= h($pageCopy['recent_title']) ?></h2>
                 </div>
-                <a class="link-arrow" href="/admin.php">Manage shelf</a>
+                <a class="link-arrow" href="/admin.php"><?= h($pageCopy['manage_shelf']) ?></a>
             </div>
             <div class="row g-3">
 <?php foreach ($recentDocuments as $document): ?>
 <?php
-    $recentTitle = (string) ($document['title_en'] ?: $document['title_ar'] ?: 'Untitled');
-    $recentTitleLang = library_text_lang($recentTitle, !empty($document['title_ar']) && empty($document['title_en']) ? 'ar' : 'en');
+    $recentTitle = library_localized_document_title($document, $lang, $pageCopy['untitled']);
+    $recentTitleLang = library_text_lang($recentTitle, $lang);
     $recentTitleDir = library_text_dir($recentTitle, $recentTitleLang);
 ?>
                 <div class="col-md-4">
                     <a class="recent-card text-decoration-none" href="/document.php?id=<?= h((string) $document['id']) ?>">
                         <span class="small text-secondary d-block mb-2"><?= h(library_language_label((string) $document['document_language'])) ?></span>
                         <strong class="d-block text-dark mb-1" lang="<?= h($recentTitleLang) ?>" dir="<?= h($recentTitleDir) ?>"><?= h($recentTitle) ?></strong>
-                        <span class="small text-secondary"><?= h((string) ($document['author'] ?: 'Unknown author')) ?></span>
+                        <span class="small text-secondary"><?= h((string) ($document['author'] ?: $pageCopy['unknown_author'])) ?></span>
                     </a>
                 </div>
 <?php endforeach; ?>
@@ -222,4 +331,4 @@ library_render_header(
     </div>
 </section>
 <?php
-library_render_footer();
\ No newline at end of file
+library_render_footer();