Nachrichten: Leerraum auf Mobile fix - flex statt berechneter Höhe

frontend/src/App.jsx

@@ -1660,7 +1660,14 @@ export default function App() {
   const activeTool = TOOLS.find(t=>t.id===active);
 
   // Mobile padding bottom für fixed nav
-  const mainStyle = { flex:1, overflowY:'auto', ...(mobile ? { paddingBottom: active==='nachrichten' ? 0 : 'calc(56px + env(safe-area-inset-bottom, 0px))' } : {}) };
+  const isNachrichten = active === 'nachrichten';
+  const mainStyle = {
+    flex:1,
+    overflowY: (mobile && isNachrichten) ? 'hidden' : 'auto',
+    display: (mobile && isNachrichten) ? 'flex' : undefined,
+    flexDirection: (mobile && isNachrichten) ? 'column' : undefined,
+    ...(mobile && !isNachrichten ? { paddingBottom:'calc(56px + env(safe-area-inset-bottom, 0px))' } : {}),
+  };
 
   return(
     <>

frontend/src/tools/nachrichten.jsx

@@ -230,9 +230,6 @@ export default function Nachrichten({ toast, mobile }) {
   // ── Layout ───────────────────────────────────────────────────────────────────
   const showList = !mobile || !activeUser;
   const showChat = !mobile || !!activeUser;
-  const h = mobile
-    ? 'calc(100dvh - 56px - env(safe-area-inset-bottom, 0px))'
-    : '100vh';
 
   if (initError) return (
     <div style={{ padding:32, color:'rgba(255,255,255,0.45)', fontFamily:'monospace', fontSize:12, lineHeight:2 }}>
@@ -242,7 +239,8 @@ export default function Nachrichten({ toast, mobile }) {
   );
 
   return (
-    <div style={{ display:'flex', height:h, overflow:'hidden', background:'#111114' }}>
+    <div style={{ display:'flex', flex:1, height: mobile ? '100%' : '100vh',
+      overflow:'hidden', background:'#111114' }}>
 
       {/* ── Konversationsliste ─────────────────────────────────────────── */}
       {showList && (