diff --git a/apps/web/messages/en.json b/apps/web/messages/en.json
index 1c8197112..f7925417a 100644
--- a/apps/web/messages/en.json
+++ b/apps/web/messages/en.json
@@ -263,6 +263,7 @@
     "fetchError": "Failed to fetch approvals",
     "noPendingApprovals": "No pending approvals",
     "selectApproval": "Select an approval to view details",
+    "backToList": "Back to list",
     "previousApproval": "Previous",
     "nextApproval": "Next",
     "holdToApproveHint": "Hold button to approve or reject",
diff --git a/apps/web/messages/zh-TW.json b/apps/web/messages/zh-TW.json
index f7a3d70a3..e375aef8f 100644
--- a/apps/web/messages/zh-TW.json
+++ b/apps/web/messages/zh-TW.json
@@ -263,6 +263,7 @@
     "fetchError": "無法取得授權清單",
     "noPendingApprovals": "目前無待授權項目",
     "selectApproval": "請選擇一個待授權項目",
+    "backToList": "返回列表",
     "previousApproval": "上一個項目",
     "nextApproval": "下一個項目",
     "holdToApproveHint": "長按按鈕以批准或拒絕",
diff --git a/apps/web/src/components/approval/conversational-view.tsx b/apps/web/src/components/approval/conversational-view.tsx
index 679f78c1d..b098891e9 100644
--- a/apps/web/src/components/approval/conversational-view.tsx
+++ b/apps/web/src/components/approval/conversational-view.tsx
@@ -70,6 +70,8 @@ export function ConversationalView({
   // 選中的 Approval
   const [selectedId, setSelectedId] = useState<string | null>(null)
   const [showShortcuts, setShowShortcuts] = useState(false)
+  // Phase 11.3: Mobile 詳情面板狀態
+  const [showMobileDetail, setShowMobileDetail] = useState(false)
 
   // 轉換為前端格式
   const approvals = useMemo(() => {
@@ -99,9 +101,17 @@ export function ConversationalView({
       } else {
         setSelectedId(null)
       }
+      // Phase 11.3: 關閉 Mobile 詳情面板
+      setShowMobileDetail(false)
     }
   }, [approvals, selectedId])
 
+  // Phase 11.3: Mobile 選擇處理
+  const handleMobileSelect = useCallback((id: string) => {
+    setSelectedId(id)
+    setShowMobileDetail(true)
+  }, [])
+
   // 導航函數
   const goToPrev = useCallback(() => {
     if (selectedIndex > 0) {
@@ -146,8 +156,15 @@ export function ConversationalView({
 
   return (
     <div className={cn('flex h-full bg-nothing-gray-50', className)}>
-      {/* 左側: 對話列表 */}
-      <div className="w-80 flex-shrink-0 border-r border-nothing-gray-200 bg-white flex flex-col">
+      {/* 左側: 對話列表 - 響應式寬度 */}
+      {/* Mobile: 全寬 | Tablet: w-64 | Desktop: w-80 */}
+      <div className={cn(
+        'flex-shrink-0 border-r border-nothing-gray-200 bg-white flex flex-col',
+        // Phase 11.3: 響應式寬度
+        'w-full md:w-64 lg:w-80',
+        // Mobile: 詳情面板打開時隱藏列表
+        showMobileDetail && 'hidden md:flex'
+      )}>
         {/* 列表 Header */}
         <div className="flex-shrink-0 p-4 border-b border-nothing-gray-100">
           <div className="flex items-center justify-between">
@@ -235,18 +252,39 @@ export function ConversationalView({
                 key={approval.id}
                 approval={approval}
                 isSelected={approval.id === selectedId}
-                onSelect={() => setSelectedId(approval.id)}
+                onSelect={() => handleMobileSelect(approval.id)}
               />
             ))
           )}
         </div>
       </div>
 
-      {/* 右側: 詳情面板 */}
-      <div className="flex-1 flex flex-col overflow-hidden relative">
+      {/* 右側: 詳情面板 - 響應式 */}
+      {/* Mobile: 全屏覆蓋 | Tablet/Desktop: 右側面板 */}
+      <div className={cn(
+        'flex flex-col overflow-hidden relative',
+        // Phase 11.3: Mobile 全屏覆蓋模式
+        showMobileDetail
+          ? 'fixed inset-0 z-40 bg-nothing-gray-50 md:relative md:inset-auto md:z-auto md:flex-1'
+          : 'hidden md:flex md:flex-1'
+      )}>
+        {/* Mobile 返回按鈕 */}
+        <div className="flex-shrink-0 flex items-center justify-between p-4 border-b border-nothing-gray-200 bg-white md:hidden">
+          <button
+            onClick={() => setShowMobileDetail(false)}
+            className="flex items-center gap-2 text-claw-blue hover:text-claw-blue/80 transition-colors"
+          >
+            <ChevronLeft className="w-5 h-5" />
+            <span className="text-sm font-medium">{t('backToList')}</span>
+          </button>
+          <div className="flex items-center gap-1 px-2 py-1 rounded-lg text-xs font-mono bg-nothing-gray-100">
+            <span>{selectedIndex + 1} / {approvals.length}</span>
+          </div>
+        </div>
+
         {/* Y 鍵長按進度指示器 */}
         {isYKeyHolding && (
-          <div className="absolute top-0 left-0 right-0 h-1 bg-nothing-gray-200 z-10">
+          <div className="absolute top-0 left-0 right-0 h-1 bg-nothing-gray-200 z-10 md:top-0">
             <div
               className="h-full bg-status-healthy transition-all duration-100"
               style={{ width: `${yKeyProgress}%` }}
@@ -255,7 +293,7 @@ export function ConversationalView({
         )}
 
         {selectedApproval ? (
-          <div className="flex-1 overflow-y-auto p-6">
+          <div className="flex-1 overflow-y-auto p-4 md:p-6">
             <ApprovalCard
               request={selectedApproval}
               onApprove={handleApprove}