diff --git a/frontend/dashboard.html b/frontend/dashboard.html
index de3af93..9e64590 100644
--- a/frontend/dashboard.html
+++ b/frontend/dashboard.html
@@ -148,6 +148,15 @@
       margin-bottom: 22px;
     }
     .full-row { margin-bottom: 22px; }
+    /* Bottom row: Activity · My submissions · Challenges side by side */
+    .bottom-grid {
+      display: grid;
+      grid-template-columns: repeat(3, 1fr);
+      gap: 22px;
+      margin-bottom: 22px;
+      align-items: start;
+    }
+    .bottom-grid > * { margin-bottom: 0; }
 
     .qa-btn {
       display: flex; align-items: center; gap: 8px;
@@ -1602,31 +1611,6 @@
         </div>
         <div id="fcw-body"></div>
       </div>
-      <!-- Combined Activity Widget (heatmap + streak calendar) -->
-      <div id="w-activity" style="display:none">
-        <div class="w-head">
-          <div class="w-title">Активность</div>
-          <div class="act-tabs">
-            <button class="act-tab active" onclick="switchActTab('heatmap',this)">Карта</button>
-            <button class="act-tab" onclick="switchActTab('calendar',this)">Месяц</button>
-          </div>
-        </div>
-        <!-- Pane 1: Heatmap -->
-        <div class="act-pane visible" id="act-heatmap-pane">
-          <div style="display:flex;justify-content:flex-end;margin-bottom:6px">
-            <div class="act-scale-btns" id="hm-scale-btns">
-              <button class="act-scale-btn" onclick="setHmScale(6,this)">6н</button>
-              <button class="act-scale-btn active" onclick="setHmScale(12,this)">12н</button>
-              <button class="act-scale-btn" onclick="setHmScale(26,this)">6м</button>
-            </div>
-          </div>
-          <div id="activity-heatmap"></div>
-        </div>
-        <!-- Pane 2: Streak calendar -->
-        <div class="act-pane" id="act-cal-pane">
-          <div id="streak-cal-body"></div>
-        </div>
-      </div>
       <!-- Day popup (floating) -->
       <div class="hm-day-popup" id="hm-day-popup" style="display:none"></div>
       <!-- Subject progress bars -->
@@ -1645,42 +1629,50 @@
     </div>
   </div>
 
-  <!-- My submissions compact widget (student only) -->
-  <div class="full-row" id="w-my-subs" style="display:none">
-    <div class="widget">
+  <!-- ZONE 4: Bottom row — Activity · My submissions · Challenges -->
+  <div class="bottom-grid">
+
+    <!-- Combined Activity Widget (heatmap + streak calendar) -->
+    <div class="widget" id="w-activity" style="display:none">
+      <div class="w-head">
+        <div class="w-title">Активность</div>
+        <div class="act-tabs">
+          <button class="act-tab active" onclick="switchActTab('heatmap',this)">Карта</button>
+          <button class="act-tab" onclick="switchActTab('calendar',this)">Месяц</button>
+        </div>
+      </div>
+      <!-- Pane 1: Heatmap -->
+      <div class="act-pane visible" id="act-heatmap-pane">
+        <div style="display:flex;justify-content:flex-end;margin-bottom:6px">
+          <div class="act-scale-btns" id="hm-scale-btns">
+            <button class="act-scale-btn" onclick="setHmScale(6,this)">6н</button>
+            <button class="act-scale-btn active" onclick="setHmScale(12,this)">12н</button>
+            <button class="act-scale-btn" onclick="setHmScale(26,this)">6м</button>
+          </div>
+        </div>
+        <div id="activity-heatmap"></div>
+      </div>
+      <!-- Pane 2: Streak calendar -->
+      <div class="act-pane" id="act-cal-pane">
+        <div id="streak-cal-body"></div>
+      </div>
+    </div>
+
+    <!-- My submissions compact widget (student only) -->
+    <div class="widget" id="w-my-subs" style="display:none">
       <div class="w-head">
         <div class="w-title">Мои сдачи</div>
         <a class="ae-btn-submit" href="/homework" style="text-decoration:none">Загрузить работу</a>
       </div>
       <div class="my-subs-list" id="my-subs-list"></div>
     </div>
-  </div>
 
-  <!-- Leaderboard (students only) -->
-  <div class="full-row" id="lb-section" style="display:none">
-    <div class="lb-widget">
-      <div class="lb-head">
-        <div class="lb-title" id="lb-title">Рейтинг</div>
-        <div style="display:flex;gap:8px;align-items:center">
-          <select class="lb-class-sel" id="lb-class-sel" onchange="loadLeaderboard()">
-            <option value="">Все</option>
-          </select>
-          <div class="lb-tabs">
-            <button class="lb-tab active" onclick="setLbPeriod('week',this)">Неделя</button>
-            <button class="lb-tab" onclick="setLbPeriod('all',this)">Всё время</button>
-          </div>
-        </div>
-      </div>
-      <div class="lb-list" id="lb-list"></div>
-    </div>
-  </div>
-
-  <!-- Challenges (students only) -->
-  <div class="full-row" id="ch-section" style="display:none">
-    <div class="widget ch-widget">
+    <!-- Challenges (students only) -->
+    <div class="widget ch-widget" id="ch-section" style="display:none">
       <div class="w-head"><div class="w-title" id="ch-title">Испытания недели</div></div>
       <div class="ch-list" id="ch-list"></div>
     </div>
+
   </div>
 
   <!-- Statistics Charts (students only) -->
@@ -1710,14 +1702,6 @@
     </div>
   </div>
 
-  <!-- Full width: Theory -->
-  <div class="full-row">
-    <div class="widget" id="w-theory-progress" style="display:none">
-      <div class="w-head"><div class="w-title">Теория — в процессе</div></div>
-      <div id="theory-progress-grid" class="theory-courses-grid"></div>
-    </div>
-  </div>
-
   <!-- Full width: Full history (hidden) -->
   <div class="full-row">
     <div class="widget" id="w-full-history" style="display:none">
@@ -1779,7 +1763,7 @@
       document.getElementById('dh-greeting').innerHTML = `${gr}, <span>${esc(user?.name?.split(' ')[0] || 'Администратор')}</span>`;
       document.getElementById('dh-sub').textContent = user?.role === 'admin' ? 'Панель администратора' : 'Панель учителя';
       // teacher/admin: hide student-only widgets, show admin compact layout
-      document.querySelectorAll('.action-zone,.main-grid,#w-theory-progress,.full-row').forEach(el => { if (el) el.style.display = 'none'; });
+      document.querySelectorAll('.action-zone,.main-grid,.bottom-grid,.full-row').forEach(el => { if (el) el.style.display = 'none'; });
       if (isAdmin) {
         // admin: full command center (redesign) instead of compact layout
         const dh = document.querySelector('.dash-header'); if (dh) dh.style.display = 'none';
@@ -4002,11 +3986,10 @@
 
     /* ── Dashboard widget visibility ──────────────────────────────────── */
     const _DASH_WIDGETS = [
-      { id: 'lb-section',       label: 'Рейтинг' },
       { id: 'ch-section',       label: 'Испытания недели' },
       { id: 'stats-section',    label: 'Статистика' },
       { id: 'w-my-subs',        label: 'Мои сдачи' },
-      { id: 'w-theory-progress',label: 'Теория' },
+      { id: 'w-activity',       label: 'Активность' },
     ];
 
     async function applyDashboardPrefs() {