diff --git a/inc/header.php b/inc/header.php
index f7cf66d..69053e9 100644
--- a/inc/header.php
+++ b/inc/header.php
@@ -8,7 +8,7 @@ require_once __DIR__ . '/../config.php';
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <title><?= htmlspecialchars($page_title ?? SITE_TITLE) ?></title>
   <link rel="icon" href="/img/favicon.ico" sizes="any">
-  <link rel="stylesheet" href="/css/style.css">
+  <link rel="stylesheet" href="/css/style.css?v=<?= filemtime(__DIR__ . '/../css/style.css') ?>">
   <script src="/js/htmx.min.js" defer></script>
   <script src="/js/idiomorph-ext.min.js" defer></script>
 </head>