diff --git a/PROJEKT.md b/PROJEKT.md
index d23395b..8abc71d 100644
--- a/PROJEKT.md
+++ b/PROJEKT.md
@@ -46,17 +46,10 @@ Maps:      Leaflet.js + OpenStreetMap (kostenlos, kein Google-Lock)
 
 ---
 
-## Implementierungsstand (aktuell: 2026-04-23, SW by-v312, APP_VER 300)
+## Implementierungsstand (aktuell: 2026-04-21, SW by-v279, APP_VER 267)
 
 ### Fertig implementiert ✅
 
-#### Desktop Multi-Column Layout (≥1024px)
-- page-container: 680px → 860px global
-- Walks: Liste (340px) links + Karte rechts nebeneinander, View-Toggle ausgeblendet
-- Forum: Rubriken in 2 Zeilen (CSS Grid, ceil(n/2) Spalten, zentriert, minmax(0,1fr))
-- Welcome: max-width 920px, Feature-Sections 2-spaltig (.welcome-sections grid)
-- Hinweis: layout.css lädt vor components.css → für Forum-Tabs ID-Selektor #page-forum nötig (Spezifität)
-
 #### SEO & Auffindbarkeit
 - `robots.txt`, `llms.txt` (für KI-Crawler), dynamische `sitemap.xml`
 - Server-gerenderte Seiten (für Google/Crawler): `/info`, `/wiki/rassen`, `/wiki/rasse/{slug}`, `/knigge`
@@ -66,7 +59,7 @@ Maps:      Leaflet.js + OpenStreetMap (kostenlos, kein Google-Lock)
 
 #### Navigation
 - Bottom-Nav: Karte · Routen · + · Tagebuch · Forum
-- Sidebar: Mein Hund (Tagebuch, Gesundheit, Übungen, Pläne) / Entdecken / Soziales / Community / Wissen (immer sichtbar, nicht mehr collapsible)
+- Sidebar: Mein Hund (Tagebuch, Gesundheit, Übungen, Pläne) / Entdecken / Soziales / Community / Wissen (collapsible)
 - Welcome-Seite und Landing-Page auf gleiche 5-Gruppen-Struktur abgestimmt
 
 #### Wiki-Rassen
diff --git a/backend/static/css/components.css b/backend/static/css/components.css
index 6f71a25..958a606 100644
--- a/backend/static/css/components.css
+++ b/backend/static/css/components.css
@@ -210,7 +210,6 @@
 }
 .by-tabs::-webkit-scrollbar { display: none; }
 
-
 .by-tab {
   flex-shrink:   0;
   padding:       var(--space-2) var(--space-3);
diff --git a/backend/static/css/layout.css b/backend/static/css/layout.css
index 761cb2f..2ba5c74 100644
--- a/backend/static/css/layout.css
+++ b/backend/static/css/layout.css
@@ -567,89 +567,6 @@
   .grid-3 { grid-template-columns: 1fr 1fr; }
 }
 
-/* ============================================================
-   Desktop Multi-Column Layouts (min-width: 1024px)
-   ============================================================ */
-@media (min-width: 1024px) {
-
-  /* Etwas breiterer Standard-Container auf großen Screens */
-  .page-container { max-width: 860px; }
-
-  /* ----------------------------------------------------------
-     WELCOME: 2-spaltige Feature-Sections, zentrierter Hero
-     ---------------------------------------------------------- */
-  .welcome-layout { max-width: 920px; }
-
-  .welcome-sections {
-    display:               grid;
-    grid-template-columns: 1fr 1fr;
-    gap:                   var(--space-4);
-    align-items:           start;
-  }
-
-  .welcome-sections .card { margin-bottom: 0; }
-
-  /* ----------------------------------------------------------
-     WALKS: Liste (links) + Karte (rechts) nebeneinander
-     ---------------------------------------------------------- */
-  #page-walks .page-container { max-width: none; }
-
-  .walks-layout {
-    flex-direction: row;
-    align-items:    stretch;
-  }
-
-  /* View-Toggle auf Desktop nicht nötig */
-  .walks-view-toggle { display: none; }
-
-  /* Beide Panels immer sichtbar */
-  #walks-list-view,
-  #walks-map-view {
-    display:        flex !important;
-    flex-direction: column;
-  }
-
-  #walks-list-view {
-    width:        340px;
-    flex-shrink:  0;
-    border-right: 1px solid var(--c-border-light);
-  }
-
-  #walks-map-view { flex: 1; }
-
-  /* Toolbar-Zeile kompakter da Toggle wegfällt */
-  #page-walks .by-toolbar { padding: var(--space-2) var(--space-4); }
-
-  /* ----------------------------------------------------------
-     FORUM: Rubriken über volle Breite, Threads darunter
-     ---------------------------------------------------------- */
-  #page-forum .page-container { max-width: 1100px; }
-
-  /* Rubriken auf genau 2 Zeilen verteilen, zentriert
-     — #page-forum nötig für Spezifität > .by-tabs (components.css lädt später) */
-  #page-forum .forum-category-tabs {
-    display:               grid;
-    grid-template-columns: repeat(var(--forum-tab-cols, 7), minmax(0, 1fr));
-    overflow:              visible;
-    gap:                   var(--space-1);
-    padding-bottom:        var(--space-2);
-  }
-
-  #page-forum .forum-category-tabs .by-tab {
-    justify-content: center;
-    text-align:      center;
-    white-space:     nowrap;
-  }
-
-  /* Suche + Threads volle Breite */
-  .forum-main-col {
-    display:        flex;
-    flex-direction: column;
-    gap:            var(--space-3);
-  }
-
-}
-
 /* ============================================================
    Phosphor Icons — SVG Sprite
    ============================================================ */
diff --git a/backend/static/index.html b/backend/static/index.html
index c567bfb..0fad607 100644
--- a/backend/static/index.html
+++ b/backend/static/index.html
@@ -169,18 +169,23 @@
         <span class="sidebar-item-badge" id="lost-badge" style="display:none">0</span>
       </div>
 
-      <span class="sidebar-section-label">Wissen</span>
-      <div class="sidebar-item" data-page="wiki">
-        <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#books"></use></svg> Wiki
-      </div>
-      <div class="sidebar-item" data-page="knigge">
-        <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#handshake"></use></svg> Knigge
-      </div>
-      <div class="sidebar-item" data-page="movies">
-        <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#film-slate"></use></svg> Filme
-      </div>
-      <div class="sidebar-item" data-page="erste-hilfe">
-        <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#first-aid"></use></svg> Erste Hilfe
+      <button class="sidebar-section-toggle" id="wissen-toggle" aria-expanded="false">
+        <span>Wissen</span>
+        <svg class="ph-icon wissen-caret" aria-hidden="true"><use href="/icons/phosphor.svg#caret-right"></use></svg>
+      </button>
+      <div class="sidebar-section-body" id="wissen-body">
+        <div class="sidebar-item" data-page="wiki">
+          <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#books"></use></svg> Wiki
+        </div>
+        <div class="sidebar-item" data-page="knigge">
+          <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#handshake"></use></svg> Knigge
+        </div>
+        <div class="sidebar-item" data-page="movies">
+          <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#film-slate"></use></svg> Filme
+        </div>
+        <div class="sidebar-item" data-page="erste-hilfe">
+          <svg class="ph-icon" aria-hidden="true"><use href="/icons/phosphor.svg#first-aid"></use></svg> Erste Hilfe
+        </div>
       </div>
 
       <div class="sidebar-item" data-page="admin" id="sidebar-admin"
diff --git a/backend/static/js/app.js b/backend/static/js/app.js
index 9eab727..ca369bb 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 = '300'; // ← bei jedem Deploy mit Frontend-Änderungen erhöhen
+const APP_VER = '290'; // ← bei jedem Deploy mit Frontend-Änderungen erhöhen
 
 const App = (() => {
 
@@ -103,6 +103,7 @@ const App = (() => {
 
     state.page = pageId;
     UI.scrollTop();
+    _expandWissenIfActive(pageId);
 
     // Seiten-Modul lazy laden (einmalig)
     _loadPage(pageId, params);
@@ -309,6 +310,12 @@ const App = (() => {
         return;
       }
 
+      // Wissen-Toggle aufklappen/zuklappen
+      if (e.target.closest('#wissen-toggle')) {
+        _toggleWissen();
+        return;
+      }
+
       // Sidebar-Item auf Mobile → schließen nach Navigation
       if (e.target.closest('#sidebar .sidebar-item')) {
         _closeSidebar();
@@ -346,6 +353,22 @@ const App = (() => {
     document.getElementById('sidebar-backdrop')?.classList.remove('visible');
   }
 
+  const _WISSEN_PAGES = new Set(['wiki', 'knigge', 'movies', 'erste-hilfe']);
+
+  function _toggleWissen(force) {
+    const toggle = document.getElementById('wissen-toggle');
+    const body   = document.getElementById('wissen-body');
+    if (!toggle || !body) return;
+    const open = force !== undefined ? force : toggle.getAttribute('aria-expanded') !== 'true';
+    toggle.setAttribute('aria-expanded', open ? 'true' : 'false');
+    body.classList.toggle('open', open);
+    try { localStorage.setItem('by_wissen_open', open ? '1' : '0'); } catch (_) {}
+  }
+
+  function _expandWissenIfActive(page) {
+    if (_WISSEN_PAGES.has(page)) _toggleWissen(true);
+  }
+
   // ----------------------------------------------------------
   // SCHNELL-HINZUFÜGEN (+ Button)
   // ----------------------------------------------------------
@@ -747,7 +770,10 @@ const App = (() => {
 
     _bindNavigation();
 
-    try { localStorage.removeItem('by_wissen_open'); } catch (_) {}
+    // Wissen-Sektion: gespeicherten Zustand wiederherstellen
+    try {
+      if (localStorage.getItem('by_wissen_open') === '1') _toggleWissen(true);
+    } catch (_) {}
 
     await _checkAuth();
 
diff --git a/backend/static/js/pages/admin.js b/backend/static/js/pages/admin.js
index 89cc5b1..1b8ca90 100644
--- a/backend/static/js/pages/admin.js
+++ b/backend/static/js/pages/admin.js
@@ -114,20 +114,17 @@ window.Page_admin = (() => {
       </svg>`;
     }
 
-    // Umami v2 liefert plain numbers, v1 liefert {value: X} — beide abfangen
-    const tv  = v => (v != null && typeof v === 'object') ? (v.value ?? 0) : (v ?? 0);
+    const tv  = v => v?.value ?? 0;
     const fmt = v => Number(v).toLocaleString('de');
 
     // Bounce Rate & Verweildauer
-    const _bounces = tv(d.today?.bounces);
-    const _visits  = tv(d.today?.visits);
-    const bounceToday = _visits > 0
-      ? ((_bounces / _visits) * 100).toFixed(0) + ' %'
-      : '—';
-    const _totaltime = tv(d.week?.totaltime);
-    const _visitsW   = tv(d.week?.visits);
-    const timeWeek = _totaltime > 0 && _visitsW > 0
-      ? Math.round(_totaltime / _visitsW) + ' s'
+    const bounceToday = d.today?.bounceRate?.value != null
+      ? (d.today.bounceRate.value * 100).toFixed(0) + ' %'
+      : (d.today?.bounces?.value != null && d.today?.visits?.value > 0
+          ? ((d.today.bounces.value / d.today.visits.value) * 100).toFixed(0) + ' %'
+          : '—');
+    const timeWeek = d.week?.totaltime?.value > 0 && d.week?.visits?.value > 0
+      ? Math.round(d.week.totaltime.value / d.week.visits.value) + ' s'
       : '—';
 
     el.innerHTML = `
diff --git a/backend/static/js/pages/forum.js b/backend/static/js/pages/forum.js
index 2399f62..6914d1a 100644
--- a/backend/static/js/pages/forum.js
+++ b/backend/static/js/pages/forum.js
@@ -104,31 +104,22 @@ window.Page_forum = (() => {
                   data-section="map">${UI.icon('users')} Mitgliederkarte</button>
         </div>
 
-        <!-- Rechte Spalte: Suche + Threads -->
-        <div class="forum-main-col">
-
-          <div class="forum-search-wrap">
-            <input type="search" class="forum-search" id="forum-search"
-                   placeholder="Forum durchsuchen…" autocomplete="off">
-          </div>
-
-          <!-- Thread-Liste / Karte / Suche -->
-          <div id="forum-main">
-            <p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Lädt…</p>
-          </div>
+        <!-- Suchleiste -->
+        <div class="forum-search-wrap">
+          <input type="search" class="forum-search" id="forum-search"
+                 placeholder="Forum durchsuchen…" autocomplete="off">
+        </div>
 
+        <!-- Thread-Liste / Karte / Suche -->
+        <div id="forum-main">
+          <p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Lädt…</p>
         </div>
 
       </div>
     `;
 
-    // Desktop: Tabs gleichmäßig auf 2 Zeilen verteilen
-    const _tabsEl = document.getElementById('forum-tabs');
-    const _tabCount = _tabsEl.querySelectorAll('.by-tab').length;
-    _tabsEl.style.setProperty('--forum-tab-cols', Math.ceil(_tabCount / 2));
-
     // Tab-Klicks
-    _tabsEl.addEventListener('click', e => {
+    document.getElementById('forum-tabs').addEventListener('click', e => {
       const btn = e.target.closest('[data-kat], [data-section]');
       if (!btn) return;
 
diff --git a/backend/static/js/pages/uebungen.js b/backend/static/js/pages/uebungen.js
index 0450d1f..30b1ff9 100644
--- a/backend/static/js/pages/uebungen.js
+++ b/backend/static/js/pages/uebungen.js
@@ -632,7 +632,7 @@ window.Page_uebungen = (() => {
           <div style="font-size:var(--text-sm);font-weight:var(--weight-semibold);
                       color:var(--c-text);line-height:1.3">${_esc(r.exercise_name)}</div>
           <div style="font-size:var(--text-xs);color:var(--c-text-secondary);line-height:1.4">${_esc(r.reason)}</div>
-          <div style="display:flex;flex-direction:column;gap:var(--space-2);margin-top:auto;padding-top:var(--space-1)">
+          <div style="display:flex;align-items:center;justify-content:space-between;margin-top:auto;padding-top:var(--space-1)">
             <div>
               <span style="font-size:var(--text-xs);color:var(--c-text-secondary)">${r.suggested_reps}× empfohlen</span>
               <span style="font-size:var(--text-xs);font-weight:700;color:${trendColor};margin-left:4px">${trend}</span>
@@ -640,7 +640,7 @@ window.Page_uebungen = (() => {
             </div>
             <button class="ueb-trainer-btn btn btn-primary"
                     data-tab="${_esc(r.tab)}" data-name="${_esc(r.exercise_name)}" data-reps="${r.suggested_reps}"
-                    style="font-size:var(--text-xs);padding:4px 10px;width:100%">
+                    style="font-size:var(--text-xs);padding:4px 10px;flex-shrink:0">
               Üben
             </button>
           </div>
@@ -656,7 +656,7 @@ window.Page_uebungen = (() => {
           Dein Plan für heute
         </span>
       </div>
-      <div style="display:flex;flex-direction:column;gap:var(--space-2)">
+      <div style="display:flex;gap:var(--space-2);align-items:stretch">
         ${cards.join('')}
       </div>`;
 
diff --git a/backend/static/js/pages/walks.js b/backend/static/js/pages/walks.js
index 34155a5..f20e43e 100644
--- a/backend/static/js/pages/walks.js
+++ b/backend/static/js/pages/walks.js
@@ -111,10 +111,6 @@ window.Page_walks = (() => {
     _view = view;
     document.querySelectorAll('.walks-view-btn').forEach(b =>
       b.classList.toggle('active', b.dataset.view === view));
-
-    // Desktop: beide Panels bleiben via CSS sichtbar
-    if (window.innerWidth >= 1024) return;
-
     document.getElementById('walks-list-view').style.display = view === 'liste' ? '' : 'none';
     document.getElementById('walks-map-view').style.display  = view === 'karte' ? '' : 'none';
 
@@ -138,14 +134,6 @@ window.Page_walks = (() => {
       );
       _renderList();
       _renderMarkers();
-      // Desktop: Karte direkt initialisieren (beide Panels sichtbar)
-      if (window.innerWidth >= 1024) {
-        UI.loadLeaflet().then(() => {
-          _initMap();
-          setTimeout(() => _map?.invalidateSize(), 150);
-          setTimeout(() => _map?.invalidateSize(), 400);
-        });
-      }
     } catch (err) {
       UI.toast.error(err.message || 'Fehler beim Laden.');
     }
diff --git a/backend/static/js/pages/welcome.js b/backend/static/js/pages/welcome.js
index 68f28b7..36360f9 100644
--- a/backend/static/js/pages/welcome.js
+++ b/backend/static/js/pages/welcome.js
@@ -28,7 +28,7 @@ window.Page_welcome = (() => {
                      || window.navigator.standalone === true;
 
     _container.innerHTML = `
-      <div class="welcome-layout" style="margin:0 auto;padding:var(--space-6) var(--space-4) var(--space-8)">
+      <div style="max-width:480px;margin:0 auto;padding:var(--space-6) var(--space-4) var(--space-8)">
 
         <!-- Hero -->
         <div style="text-align:center;margin-bottom:var(--space-8)">
@@ -68,9 +68,7 @@ window.Page_welcome = (() => {
           </div>
         </button>
 
-        <!-- Feature-Abschnitte (auf Desktop 2-spaltig) -->
-        <div class="welcome-sections">
-
+        <!-- Features: Mein Hund -->
         ${_featureCard('Mein Hund', [
           ['book-open',       'Tagebuch',        'Momente, Fotos und Meilensteine festhalten', 'diary'],
           ['first-aid',       'Gesundheit',      'Impfungen, Tierarztbesuche & Medikamente',   'health'],
@@ -78,18 +76,21 @@ window.Page_welcome = (() => {
           ['clipboard-text',  'Trainingspläne',  'Strukturierte Pläne für jedes Lernziel',     'trainingsplaene'],
         ])}
 
+        <!-- Features: Entdecken -->
         ${_featureCard('Entdecken', [
           ['map-trifold',   'Karte',   'Orte, Routen und Meldungen in der Nähe',  'map'],
           ['path',          'Routen',  'GPS-Routen aufzeichnen und bewerten',      'routes'],
           ['calendar-dots', 'Events',  'Turniere und Veranstaltungen',             'events'],
         ])}
 
+        <!-- Features: Soziales -->
         ${_featureCard('Soziales', [
           ['users',            'Freunde',     'Verbinde dich mit anderen Hundebesitzern', 'friends'],
           ['chat-circle-dots', 'Nachrichten', 'Private Chats mit deinen Freunden',        'chat'],
           ['bell',             'Aktuelles',   'Benachrichtigungen und Neuigkeiten',        'notifications'],
         ])}
 
+        <!-- Features: Community -->
         ${_featureCard('Community', [
           ['warning-octagon',  'Giftköder-Alarm',  'Warnungen sofort melden und empfangen',  'poison'],
           ['paw-print',        'Gassi-Treffen',    'Hunde-Dates mit anderen Besitzern',       'walks'],
@@ -98,6 +99,7 @@ window.Page_welcome = (() => {
           ['magnifying-glass', 'Verlorene Hunde',  'Hilf vermisste Hunde zu finden',          'lost'],
         ])}
 
+        <!-- Features: Wissen -->
         ${_featureCard('Wissen', [
           ['books',      'Wiki',       'Rassendatenbank, Gesundheits-Wiki, Quiz', 'wiki'],
           ['handshake',  'Knigge',     'Regeln, Begegnungen, Leinenpflicht',      'knigge'],
@@ -105,8 +107,6 @@ window.Page_welcome = (() => {
           ['first-aid',  'Erste Hilfe','Notfallratgeber für häufige Situationen', 'erste-hilfe'],
         ])}
 
-        </div>
-
         <!-- App installieren -->
         <div class="card" style="margin-bottom:var(--space-5)" id="install-section">
           <div style="padding:var(--space-3) var(--space-4);
diff --git a/backend/static/sw.js b/backend/static/sw.js
index 812f0cd..44879f1 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-v312';
+const CACHE_VERSION = 'by-v302';
 const CACHE_STATIC  = `${CACHE_VERSION}-static`;
 const CACHE_TILES   = 'ban-yaro-tiles-v1';  // bleibt über SW-Updates erhalten