diff --git a/public/.htaccess b/public/.htaccess
index 77351b7..5fe8181 100644
--- a/public/.htaccess
+++ b/public/.htaccess
@@ -59,3 +59,6 @@ RewriteRule ^sitemap\.xml$ /sitemap.php [L]
 # Ajoute .php si le fichier correspondant existe
 RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI}.php -f
 RewriteRule ^(.+?)/?$ /$1.php [L,QSA]
+
+# 404 intelligent : redirige vers l'article le plus proche
+ErrorDocument 404 /index.php?action=not_found
diff --git a/public/index.php b/public/index.php
index ac36f28..f88a8db 100644
--- a/public/index.php
+++ b/public/index.php
@@ -22,10 +22,38 @@ $action = $_GET['action'] ?? 'list';
 $uuid   = $_GET['uuid']   ?? '';
 $slug   = $_GET['slug']   ?? '';
 
-$_noindexActions = ['create', 'edit', 'admin', 'categories', 'diff', 'add_files', 'import_image', 'import_image_step2', 'sources', 'profile', 'delete_file', 'delete_external_link', 'rename_category', 'delete_category', 'toggle_private_category', 'admin_save_site'];
+$_noindexActions = ['create', 'edit', 'admin', 'categories', 'diff', 'add_files', 'import_image', 'import_image_step2', 'sources', 'profile', 'delete_file', 'delete_external_link', 'rename_category', 'delete_category', 'toggle_private_category', 'admin_save_site', 'not_found'];
 $metaRobots = in_array($action, $_noindexActions, true) ? 'noindex, nofollow' : null;
 unset($_noindexActions);
 
+// ─── Recherche de l'article le plus proche et redirection 301 ────────────────
+function searchAndRedirect(string $rawPath, ArticleManager $articles): void
+{
+    require_once BASE_PATH . '/src/SearchEngine.php';
+    $query = (string)preg_replace('/\s{2,}/', ' ', trim(
+        (string)preg_replace('/[^a-zA-ZÀ-ÿ0-9\s]/u', ' ', str_replace(['-', '_', '/'], ' ', $rawPath))
+    ));
+    if ($query === '') {
+        return;
+    }
+    $privateCats = $articles->getPrivateCategories();
+    $pool = array_values(array_filter(
+        $articles->getAll(true),
+        static function (array $a) use ($privateCats): bool {
+            if (strtotime((string)($a['published_at'] ?? '')) > time()) {
+                return false;
+            }
+            $cat = trim($a['category'] ?? '');
+            return $cat === '' || !in_array($cat, $privateCats, true);
+        }
+    ));
+    $results = (new SearchEngine())->search($query, $pool);
+    if (!empty($results)) {
+        header('Location: /post/' . rawurlencode($results[0]['article']['slug'] ?? ''), true, 301);
+        exit;
+    }
+}
+
 // ─── Extraction de métadonnées depuis une URL ────────────────────────────────
 function fetchUrlMeta(string $url): array
 {
@@ -472,6 +500,7 @@ switch ($action) {
     case 'view':
         $article = $slug !== '' ? $articles->getBySlug($slug) : null;
         if (!$article) {
+            searchAndRedirect($slug, $articles);
             http_response_code(404);
             echo 'Article introuvable.';
             exit;
@@ -1826,6 +1855,29 @@ switch ($action) {
         include BASE_PATH . '/templates/search.php';
         break;
 
+    case 'not_found':
+        $notFoundPath = trim(
+            (string)(parse_url($_SERVER['REDIRECT_URL'] ?? $_SERVER['REQUEST_URI'] ?? '', PHP_URL_PATH) ?? ''),
+            '/'
+        );
+        if ($notFoundPath !== '') {
+            searchAndRedirect($notFoundPath, $articles);
+        }
+        http_response_code(404);
+        ob_start();
+        ?>
+        <div class="container py-5 text-center">
+            <h1 class="h2 mb-3">Page introuvable</h1>
+            <p class="text-muted mb-4">Cette adresse ne correspond à aucun article.<br>Vous avez peut-être suivi un ancien lien.</p>
+            <a href="/" class="btn btn-primary">← Retour à l'accueil</a>
+        </div>
+        <?php
+        $content    = ob_get_clean();
+        $title      = '404 — ' . siteTitle();
+        $metaRobots = 'noindex, nofollow';
+        include BASE_PATH . '/templates/layout.php';
+        break;
+
     case 'list':
     default:
         $privateCats  = $articles->getPrivateCategories();