diff --git a/backend/main.py b/backend/main.py
index dc31b11..9218a81 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -327,7 +327,7 @@ MEDIA_DIR = os.getenv("MEDIA_DIR", "/data/media")
 os.makedirs(MEDIA_DIR, exist_ok=True)
 app.mount("/media", StaticFiles(directory=MEDIA_DIR), name="media")
 
-APP_VER = "783"  # muss mit APP_VER in app.js übereinstimmen
+APP_VER = "784"  # muss mit APP_VER in app.js übereinstimmen
 
 @app.get("/.well-known/assetlinks.json")
 async def assetlinks():
diff --git a/backend/static/index.html b/backend/static/index.html
index dd4b114..7213d86 100644
--- a/backend/static/index.html
+++ b/backend/static/index.html
@@ -575,10 +575,10 @@
 <div id="modal-container"></div>
 
 <!-- JS: Reihenfolge ist wichtig — erst Basis, dann Features -->
-<script src="/js/api.js?v=783"></script>
-<script src="/js/ui.js?v=783"></script>
-<script src="/js/app.js?v=783"></script>
-<script src="/js/worlds.js?v=783"></script>
+<script src="/js/api.js?v=784"></script>
+<script src="/js/ui.js?v=784"></script>
+<script src="/js/app.js?v=784"></script>
+<script src="/js/worlds.js?v=784"></script>
 
 <!-- Feature-Seiten werden lazy geladen -->
 
diff --git a/backend/static/js/app.js b/backend/static/js/app.js
index 8d6c130..163f8de 100644
--- a/backend/static/js/app.js
+++ b/backend/static/js/app.js
@@ -3,7 +3,7 @@
    Router, State-Management, Navigation, Initialisierung.
    ============================================================ */
 
-const APP_VER     = '783'; // ← bei jedem Deploy mit Frontend-Änderungen erhöhen
+const APP_VER     = '784'; // ← bei jedem Deploy mit Frontend-Änderungen erhöhen
 const APP_VERSION = '1.5.0'; // ← semantische Version, wird bei make release gesetzt
 const IS_STAGING  = location.hostname === 'staging.banyaro.app';
 // Cache-Bust-Parameter nach Update-Reload sofort entfernen
diff --git a/backend/static/js/worlds.js b/backend/static/js/worlds.js
index ef13b02..33fb509 100644
--- a/backend/static/js/worlds.js
+++ b/backend/static/js/worlds.js
@@ -917,23 +917,51 @@ window.Worlds = (() => {
     } catch { return dog.foto_url || null; }
   }
 
+  let _bgUrl = null; // aktuell gesetztes Hintergrundbild
+
+  function _applyBgOrientation() {
+    const ov    = document.getElementById('worlds-overlay');
+    const track = document.getElementById('worlds-track');
+    if (!ov || !track || !_bgUrl) return;
+    const portrait = window.matchMedia('(orientation: portrait)').matches;
+    if (portrait) {
+      // Panorama: Bild über alle drei Welten, scrollt mit dem Swipe
+      ov.style.backgroundImage    = '';
+      track.style.backgroundImage    = `url('${_bgUrl}')`;
+      track.style.backgroundSize     = 'cover';
+      track.style.backgroundPosition = 'center 40%';
+      track.style.backgroundRepeat   = 'no-repeat';
+    } else {
+      // Vollbild pro Welt (Landscape / Desktop)
+      track.style.backgroundImage    = '';
+      ov.style.backgroundImage    = `url('${_bgUrl}')`;
+      ov.style.backgroundSize     = 'cover';
+      ov.style.backgroundPosition = 'center 40%';
+      ov.style.backgroundRepeat   = 'no-repeat';
+    }
+  }
+
+  // Orientierungswechsel → Bild neu setzen
+  window.matchMedia('(orientation: portrait)').addEventListener('change', _applyBgOrientation);
+
   function _applyBgImage(url) {
-    const ov = document.getElementById('worlds-overlay');
-    if (!ov) return;
+    const ov    = document.getElementById('worlds-overlay');
+    const track = document.getElementById('worlds-track');
+    if (!ov || !track) return;
     if (url) {
       const toLoad = new Image();
       toLoad.onload = () => {
         _hasBgPhoto = true;
-        ov.style.backgroundImage    = `url('${url}')`;
-        ov.style.backgroundSize     = 'cover';
-        ov.style.backgroundPosition = 'center 40%';
-        ov.style.backgroundRepeat   = 'no-repeat';
+        _bgUrl = url;
+        _applyBgOrientation();
         document.getElementById('wh-photo-hint')?.remove();
       };
       toLoad.onerror = () => _applyBgImage(null);
       toLoad.src = url;
     } else {
       _hasBgPhoto = false;
+      _bgUrl = null;
+      track.style.backgroundImage    = '';
       ov.style.backgroundImage = 'linear-gradient(160deg,#1a1f35 0%,#16213e 33%,#1a2535 67%,#0f1921 100%)';
       ov.style.backgroundSize  = '100% 100%';
     }
@@ -979,8 +1007,7 @@ window.Worlds = (() => {
     const staleMin   = Math.max(weatherObj.ageMin || 0, dogsObj.ageMin || 0);
 
     // Panorama-Bild setzen (nur wenn noch kein Bild vorhanden)
-    const ov = document.getElementById('worlds-overlay');
-    if (dog && !ov?.style.backgroundImage?.startsWith('url')) {
+    if (dog && !_bgUrl) {
       _loadDailyImage(dog).then(_applyBgImage);
     } else if (!dog) { _applyBgImage(null); }
 
diff --git a/backend/static/sw.js b/backend/static/sw.js
index f38d799..fbdb8fe 100644
--- a/backend/static/sw.js
+++ b/backend/static/sw.js
@@ -3,7 +3,7 @@
    Offline-Cache + Push Notifications + Tile-Cache
    ============================================================ */
 
-const CACHE_VERSION = 'by-v783';
+const CACHE_VERSION = 'by-v784';
 const CACHE_STATIC  = `${CACHE_VERSION}-static`;
 const CACHE_TILES   = 'ban-yaro-tiles-v1';  // bleibt über SW-Updates erhalten
 const CACHE_API     = 'ban-yaro-api-v1';    // API-Response-Cache