diff --git a/public/index.html b/public/index.html
index 4e447d6..625a9fe 100644
--- a/public/index.html
+++ b/public/index.html
@@ -17,9 +17,9 @@
   <link rel="preconnect" href="https://unpkg.com" crossorigin />
   <link rel="dns-prefetch" href="https://openweathermap.org" />
 
-  <!-- Preload: kritische Skripte (frühzeitig laden, bevor Parser sie findet) -->
-  <link rel="preload" href="/api.js"    as="script" crossorigin />
-  <link rel="preload" href="/router.js" as="script" crossorigin />
+  <!-- Preload: kritische ES-Module (modulepreload ist korrekt für type="module") -->
+  <link rel="modulepreload" href="/api.js" />
+  <link rel="modulepreload" href="/router.js" />
 
   <!-- Styles -->
   <link rel="stylesheet" href="/styles/tokens.css" />
@@ -53,14 +53,6 @@
   <script type="module" src="/router.js"></script>
 
   <!-- Service Worker registrieren -->
-  <script>
-    if ('serviceWorker' in navigator) {
-      window.addEventListener('load', () => {
-        navigator.serviceWorker.register('/sw.js').catch((err) => {
-          console.warn('[SW] Registrierung fehlgeschlagen:', err);
-        });
-      });
-    }
-  </script>
+  <script src="/sw-register.js" defer></script>
 </body>
 </html>
diff --git a/public/sw-register.js b/public/sw-register.js
new file mode 100644
index 0000000..d198577
--- /dev/null
+++ b/public/sw-register.js
@@ -0,0 +1,13 @@
+/**
+ * Modul: Service Worker Registrierung
+ * Zweck: Ausgelagert aus index.html um CSP-Inline-Script-Verletzung zu vermeiden
+ * Abhängigkeiten: keine
+ */
+
+if ('serviceWorker' in navigator) {
+  window.addEventListener('load', () => {
+    navigator.serviceWorker.register('/sw.js').catch((err) => {
+      console.warn('[SW] Registrierung fehlgeschlagen:', err);
+    });
+  });
+}
diff --git a/public/sw.js b/public/sw.js
index 94da0b6..bee6168 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -23,6 +23,7 @@ const APP_SHELL = [
   '/index.html',
   '/api.js',
   '/router.js',
+  '/sw-register.js',
   '/styles/tokens.css',
   '/styles/reset.css',
   '/styles/layout.css',