diff --git a/backend/static/css/layout.css b/backend/static/css/layout.css
index 65b62e3..e3f44b5 100644
--- a/backend/static/css/layout.css
+++ b/backend/static/css/layout.css
@@ -592,7 +592,7 @@
   /* ----------------------------------------------------------
      WALKS: Liste (links) + Karte (rechts) nebeneinander
      ---------------------------------------------------------- */
-  #page-walks .page-container { max-width: none; }
+  #page-walks .page-container { max-width: 1100px; }
 
   .walks-layout {
     flex-direction: row;
@@ -620,6 +620,20 @@
   /* Toolbar-Zeile kompakter da Toggle wegfällt */
   #page-walks .by-toolbar { padding: var(--space-2) var(--space-4); }
 
+  /* ----------------------------------------------------------
+     CHAT: Split-Pane zentriert mit max-width
+     ---------------------------------------------------------- */
+  #page-chat .page-body {
+    display:         flex;
+    flex-direction:  column;
+    align-items:     stretch;
+    max-width:       1100px;
+    margin:          0 auto;
+    width:           100%;
+  }
+
+  #chat-split { min-height: 600px; }
+
   /* ----------------------------------------------------------
      FORUM: Rubriken über volle Breite, Threads darunter
      ---------------------------------------------------------- */
diff --git a/backend/static/js/app.js b/backend/static/js/app.js
index 0a98f15..da4e856 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 = '387'; // ← bei jedem Deploy mit Frontend-Änderungen erhöhen
+const APP_VER = '388'; // ← bei jedem Deploy mit Frontend-Änderungen erhöhen
 
 const App = (() => {
 
diff --git a/backend/static/js/pages/chat.js b/backend/static/js/pages/chat.js
index acd9c64..f5d7b63 100644
--- a/backend/static/js/pages/chat.js
+++ b/backend/static/js/pages/chat.js
@@ -59,8 +59,7 @@ window.Page_chat = (() => {
       // Split-Pane: linke Spalte bleibt, rechte zeigt Placeholder
       if (!document.getElementById('chat-split')) {
         _container.innerHTML = `
-          <div id="chat-split" style="display:flex;flex:1;min-height:0;overflow:hidden;
-               position:absolute;inset:0">
+          <div id="chat-split" style="display:flex;flex:1;min-height:0;overflow:hidden;width:100%">
             <div id="chat-list-pane" style="width:320px;flex-shrink:0;display:flex;
                  flex-direction:column;border-right:1px solid var(--c-border);
                  background:var(--c-surface);min-height:0">
diff --git a/backend/static/sw.js b/backend/static/sw.js
index d0447e5..4944c02 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-v407';
+const CACHE_VERSION = 'by-v408';
 const CACHE_STATIC  = `${CACHE_VERSION}-static`;
 const CACHE_TILES   = 'ban-yaro-tiles-v1';  // bleibt über SW-Updates erhalten