Assets/Scripts/UI/CardSystem/AlbumViewPage.cs

@@ -44,7 +44,9 @@ namespace UI.CardSystem
         private Input.InputMode _previousInputMode;
         private List<StateMachine.Card> _activeCards = new List<StateMachine.Card>();
         private const int MAX_VISIBLE_CARDS = 3;
-
+        private List<StateMachine.Card> _pendingCornerCards = new List<StateMachine.Card>();
+        private const int MAX_PENDING_CORNER = 3;
+        
         internal override void OnManagedStart()
         {
             // Discover zone tabs from container
@@ -679,5 +681,87 @@ namespace UI.CardSystem
             }
             return null;
         }
+        
+        public void SpawnPendingCornerCards()
+        {
+            if (cardPrefab == null || bottomRightSlots == null) return;
+            CleanupPendingCornerCards();
+            for (int i = 0; i < MAX_PENDING_CORNER; i++)
+            {
+                var slot = FindSlotByIndex(i);
+                if (slot == null) break;
+                GameObject cardObj = Instantiate(cardPrefab, bottomRightSlots.transform);
+                var card = cardObj.GetComponent<StateMachine.Card>();
+                if (card != null)
+                {
+                    card.SetupForAlbumPending();
+                    card.AssignToSlot(slot, true);
+                    _pendingCornerCards.Add(card);
+                }
+                else
+                {
+                    Destroy(cardObj);
+                }
+            }
+        }
+        
+        private void CleanupPendingCornerCards()
+        {
+            foreach (var c in _pendingCornerCards)
+            {
+                if (c != null) Destroy(c.gameObject);
+            }
+            _pendingCornerCards.Clear();
+        }
+        
+        public void HandlePendingCardDragStart(StateMachine.Card cornerCard)
+        {
+            // Select smart pending card data
+            var selected = SelectSmartPendingCard();
+            if (selected == null)
+            {
+                return; // no pending data
+            }
+            cornerCard.Context.SetupCard(selected);
+            // Navigate album to page
+            int targetPage = FindPageForCard(selected);
+            if (targetPage >= 0)
+            {
+                NavigateToAlbumPage(targetPage);
+            }
+            // Begin flip state
+            cornerCard.ChangeState("FlippingPendingState");
+        }
+        
+        private CardData SelectSmartPendingCard()
+        {
+            if (CardSystemManager.Instance == null) return null;
+            var pending = CardSystemManager.Instance.GetPendingRevealCards();
+            if (pending.Count == 0) return null;
+            // Try current page match
+            var pageDefs = GetDefinitionsOnCurrentPage();
+            var match = pending.Find(c => pageDefs.Contains(c.DefinitionId));
+            if (match != null) return match;
+            // Fallback random
+            int idx = Random.Range(0, pending.Count);
+            return pending[idx];
+        }
+        
+        private List<string> GetDefinitionsOnCurrentPage()
+        {
+            // Placeholder: gather from slots on current page
+            return new List<string>();
+        }
+        
+        private int FindPageForCard(CardData data)
+        {
+            // Placeholder: map definition to page index
+            return -1;
+        }
+        
+        private void NavigateToAlbumPage(int pageIndex)
+        {
+            // Placeholder: call book/page flip controller
+        }
     }
 }

Assets/Scripts/UI/CardSystem/CardBack.cs

@@ -0,0 +1,23 @@
+using UnityEngine;
+using UnityEngine.UI;
+
+namespace UI.CardSystem
+{
+    /// <summary>
+    /// Simple component representing card back visuals; toggle visibility.
+    /// </summary>
+    public class CardBack : MonoBehaviour
+    {
+        [SerializeField] private Image backImage;
+        
+        public void Show()
+        {
+            gameObject.SetActive(true);
+        }
+        
+        public void Hide()
+        {
+            gameObject.SetActive(false);
+        }
+    }
+}

Assets/Scripts/UI/CardSystem/CardBack.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 37d815ba7b02481786cc1953678a3e8e
+timeCreated: 1763322207

Assets/Scripts/UI/CardSystem/StateMachine/Card.cs

@@ -56,37 +56,63 @@ namespace UI.CardSystem.StateMachine
         protected override void OnDragStartedHook()
         {
             base.OnDragStartedHook();
-            
-            // Transition to dragging state when drag begins
-            Logging.Debug($"[Card] Drag started on {CardData?.Name}, transitioning to DraggingState");
-            ChangeState("DraggingState");
+            string current = GetCurrentStateName();
+            if (current == "PendingFaceDownState")
+            {
+                // Notify AlbumViewPage to assign data & flip
+                var albumPage = FindObjectOfType<AlbumViewPage>();
+                if (albumPage != null)
+                {
+                    albumPage.HandlePendingCardDragStart(this);
+                }
+                // State change will be triggered by album page after data assignment
+            }
+            else
+            {
+                Logging.Debug($"[Card] Drag started on {CardData?.Name}, transitioning to DraggingState");
+                ChangeState("DraggingState");
+            }
         }
         
         protected override void OnDragEndedHook()
         {
             base.OnDragEndedHook();
-            
-            // Check if we dropped in a valid album slot
-            if (CurrentSlot is AlbumCardSlot albumSlot)
+            string current = GetCurrentStateName();
+            if (current == "DraggingState")
             {
-                Logging.Debug($"[Card] Dropped in album slot, transitioning to PlacedInSlotState");
-                
-                // Set the parent slot on PlacedInSlotState
-                var placedState = GetStateComponent<States.CardPlacedInSlotState>("PlacedInSlotState");
-                if (placedState != null)
+                // Existing logic
+                if (CurrentSlot is AlbumCardSlot albumSlot)
                 {
-                    placedState.SetParentSlot(albumSlot);
+                    Logging.Debug($"[Card] Dropped in album slot, transitioning to PlacedInSlotState");
+                    var placedState = GetStateComponent<States.CardPlacedInSlotState>("PlacedInSlotState");
+                    if (placedState != null)
+                    {
+                        placedState.SetParentSlot(albumSlot);
+                    }
+                    ChangeState("PlacedInSlotState");
+                    OnPlacedInAlbumSlot?.Invoke(this, albumSlot);
+                }
+                else
+                {
+                    Logging.Debug("[Card] Dropped outside valid slot, returning to RevealedState");
+                    ChangeState("RevealedState");
                 }
-                
-                ChangeState("PlacedInSlotState");
-                
-                // Notify listeners (AlbumViewPage) that this pending card was placed
-                OnPlacedInAlbumSlot?.Invoke(this, albumSlot);
             }
-            else
+            else if (current == "DraggingRevealedState")
             {
-                Logging.Debug($"[Card] Dropped outside valid slot, returning to RevealedState");
-                ChangeState("RevealedState");
+                // Pending revealed drag state end
+                if (CurrentSlot is AlbumCardSlot albumSlot)
+                {
+                    var placedState = GetStateComponent<States.CardPlacedInSlotState>("PlacedInSlotState");
+                    if (placedState != null) placedState.SetParentSlot(albumSlot);
+                    ChangeState("PlacedInSlotState");
+                    OnPlacedInAlbumSlot?.Invoke(this, albumSlot);
+                }
+                else
+                {
+                    // Return to corner face-down
+                    ChangeState("PendingFaceDownState");
+                }
             }
         }
         
@@ -148,6 +174,17 @@ namespace UI.CardSystem.StateMachine
             }
         }
         
+        /// <summary>
+        /// Setup for album pending state (starts at PendingFaceDownState)
+        /// Dragging is ENABLED; state will assign data when dragged
+        /// </summary>
+        public void SetupForAlbumPending()
+        {
+            // Start with no data; state will assign when dragged
+            SetupCard(null, "PendingFaceDownState");
+            SetDraggingEnabled(true);
+        }
+        
         /// <summary>
         /// Transition to a specific state
         /// </summary>

Assets/Scripts/UI/CardSystem/StateMachine/States/CardDraggingRevealedState.cs

@@ -0,0 +1,39 @@
+using Core.SaveLoad;
+using UnityEngine;
+
+namespace UI.CardSystem.StateMachine.States
+{
+    /// <summary>
+    /// Dragging revealed state for pending cards after flip; minimal overlay of CardDraggingState but no badges.
+    /// </summary>
+    public class CardDraggingRevealedState : AppleState
+    {
+        private CardContext context;
+        private Vector3 originalScale;
+        
+        private void Awake()
+        {
+            context = GetComponentInParent<CardContext>();
+        }
+        
+        public override void OnEnterState()
+        {
+            if (context == null) return;
+            if (context.CardDisplay != null)
+            {
+                context.CardDisplay.gameObject.SetActive(true);
+                context.CardDisplay.transform.localRotation = Quaternion.Euler(0,0,0);
+            }
+            originalScale = context.RootTransform.localScale;
+            context.RootTransform.localScale = originalScale * 1.15f;
+        }
+        
+        private void OnDisable()
+        {
+            if (context?.RootTransform != null)
+            {
+                context.RootTransform.localScale = originalScale;
+            }
+        }
+    }
+}

Assets/Scripts/UI/CardSystem/StateMachine/States/CardDraggingRevealedState.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: ce2483293cdd4680b5095afc1fcb2fde
+timeCreated: 1763322199

Assets/Scripts/UI/CardSystem/StateMachine/States/CardFlippingPendingState.cs

@@ -0,0 +1,57 @@
+using Core;
+using Core.SaveLoad;
+using UnityEngine;
+
+namespace UI.CardSystem.StateMachine.States
+{
+    /// <summary>
+    /// Handles flipping a pending face-down card after data assignment.
+    /// Transitions to DraggingRevealedState when flip completes.
+    /// </summary>
+    public class CardFlippingPendingState : AppleState
+    {
+        private CardContext context;
+        private GameObject cardBack;
+        
+        private void Awake()
+        {
+            context = GetComponentInParent<CardContext>();
+            if (context != null)
+            {
+                var backTransform = context.RootTransform.Find("CardBack");
+                if (backTransform != null) cardBack = backTransform.gameObject;
+            }
+        }
+        
+        public override void OnEnterState()
+        {
+            if (context == null) return;
+            // Ensure card back visible and front hidden at start
+            if (cardBack != null) cardBack.SetActive(true);
+            if (context.CardDisplay != null) context.CardDisplay.gameObject.SetActive(false);
+            
+            // Optional: album navigation
+            var albumPage = Object.FindObjectOfType<AlbumViewPage>();
+            if (albumPage != null && context.CardData != null)
+            {
+                int targetPage = albumPage.FindPageForCard(context.CardData); // placeholder; method may be private
+            }
+            
+            if (context.Animator != null)
+            {
+                Transform back = cardBack != null ? cardBack.transform : null;
+                Transform front = context.CardDisplay != null ? context.CardDisplay.transform : null;
+                context.Animator.PlayFlip(back, front, onComplete: () =>
+                {
+                    context.StateMachine.ChangeState("DraggingRevealedState");
+                });
+            }
+            else
+            {
+                if (cardBack != null) cardBack.SetActive(false);
+                if (context.CardDisplay != null) context.CardDisplay.gameObject.SetActive(true);
+                context.StateMachine.ChangeState("DraggingRevealedState");
+            }
+        }
+    }
+}

Assets/Scripts/UI/CardSystem/StateMachine/States/CardFlippingPendingState.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: edffabfce37d42ceac2194c23470acab
+timeCreated: 1763322190

Assets/Scripts/UI/CardSystem/StateMachine/States/CardPendingFaceDownState.cs

@@ -0,0 +1,39 @@
+using Core.SaveLoad;
+using UnityEngine;
+
+namespace UI.CardSystem.StateMachine.States
+{
+    /// <summary>
+    /// Card is in pending face-down state in corner, awaiting drag.
+    /// Front hidden, back visible (assumes CardBack child exists).
+    /// </summary>
+    public class CardPendingFaceDownState : AppleState
+    {
+        private CardContext context;
+        private GameObject cardBack;
+        
+        private void Awake()
+        {
+            context = GetComponentInParent<CardContext>();
+            if (context != null)
+            {
+                var backTransform = context.RootTransform.Find("CardBack");
+                if (backTransform != null) cardBack = backTransform.gameObject;
+            }
+        }
+        
+        public override void OnEnterState()
+        {
+            if (context == null) return;
+            // Hide front
+            if (context.CardDisplay != null)
+            {
+                context.CardDisplay.gameObject.SetActive(false);
+            }
+            // Show back
+            if (cardBack != null) cardBack.SetActive(true);
+            // Scale
+            context.RootTransform.localScale = context.OriginalScale * 0.8f;
+        }
+    }
+}

Assets/Scripts/UI/CardSystem/StateMachine/States/CardPendingFaceDownState.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 6fab9d595905435b82253cd4d1bf49de
+timeCreated: 1763322180

docs/album_placement_flow_proposal.md

@@ -0,0 +1,460 @@
+# Album Card Placement Flow - Refactored Design
+
+## Current State Analysis
+
+### Existing Flow (Pre-Refactor):
+1. Pending cards spawn face-up in bottom-right slots
+2. User drags card to album slot
+3. Card placement triggers inventory move
+4. Next card spawns
+
+### Problems:
+- Cards spawn face-up (should be face-down)
+- No "smart selection" from pending queue based on current album page
+- No auto-flip to correct album page when card is picked up
+- States don't support "hold to reveal" behavior
+
+---
+
+## Proposed New Flow
+
+### Visual Journey:
+```
+[Face-Down Card in Corner] 
+    ↓ (user holds/drags)
+[Card Flips to Reveal] + [Album auto-flips to correct page]
+    ↓ (user drags over album)
+[Card hovers over slot]
+    ↓ (user releases)
+[Card snaps to slot] → [Revealed State in slot]
+```
+
+### Technical Implementation:
+
+---
+
+## 1. New Card States
+
+### A. `CardPendingFaceDownState`
+**Purpose:** Initial state for cards in pending corner slots
+**Visuals:** 
+- Card back visible (card front hidden)
+- Small scale (to fit in corner slot)
+- Idle in corner
+
+**Behavior:**
+- Does NOT respond to clicks
+- Responds to drag start (OnDragStarted)
+- On drag start → trigger smart card selection + flip animation
+
+**Transitions:**
+- OnDragStarted → `CardFlippingPendingState`
+
+---
+
+### B. `CardFlippingPendingState`
+**Purpose:** Transition state while card flips and album navigates
+**Visuals:**
+- Flip animation (card back → card front)
+- Card follows cursor during flip
+
+**Behavior:**
+- Play flip animation (uses CardAnimator.PlayFlip)
+- Emit event to AlbumViewPage to navigate to card's page
+- Wait for flip animation complete
+
+**Transitions:**
+- OnFlipComplete → `CardDraggingRevealedState`
+
+---
+
+### C. `CardDraggingRevealedState`
+**Purpose:** Card is revealed and being dragged around album
+**Visuals:**
+- Card front visible
+- No badges (clean revealed state)
+- Follow cursor/drag position
+- Slight scale-up while dragging
+
+**Behavior:**
+- Respond to drag position updates
+- Detect when hovering over valid AlbumCardSlot
+- Visual feedback when over valid slot
+- On drag end → snap to slot if valid, otherwise return to corner
+
+**Transitions:**
+- OnDragEnd (over valid slot) → slot's `PlacedInSlotState`
+- OnDragEnd (invalid) → `CardPendingFaceDownState` (return to corner, flip back)
+
+---
+
+## 2. Smart Card Selection System
+
+### AlbumViewPage Responsibilities:
+
+```csharp
+public class AlbumViewPage
+{
+    private List<CardData> _pendingQueue; // All pending cards
+    private List<Card> _cornerCards; // 3 face-down card GameObjects in corner
+    private int _currentAlbumPageIndex;
+    
+    /// <summary>
+    /// When user starts dragging ANY corner card, we pick which pending card to reveal
+    /// </summary>
+    private void OnCornerCardDragStarted(Card cornerCard)
+    {
+        // 1. Get current album page's expected cards
+        var currentPageSlots = GetSlotsOnCurrentPage();
+        var currentPageDefinitions = currentPageSlots
+            .Select(slot => slot.TargetCardDefinition)
+            .ToList();
+        
+        // 2. Try to find a pending card that belongs on this page
+        CardData selectedCard = _pendingQueue.FirstOrDefault(card => 
+            currentPageDefinitions.Any(def => def.Id == card.DefinitionId && def.Rarity == card.Rarity)
+        );
+        
+        // 3. If none on current page, pick random pending
+        if (selectedCard == null)
+        {
+            selectedCard = _pendingQueue[Random.Range(0, _pendingQueue.Count)];
+            
+            // Navigate album to the page where this card belongs
+            int targetPage = FindPageForCard(selectedCard);
+            NavigateToPage(targetPage);
+        }
+        
+        // 4. Assign the selected card data to the corner card being dragged
+        cornerCard.Context.SetupCard(selectedCard);
+        
+        // 5. Trigger flip (handled by state)
+        cornerCard.Context.StateMachine.ChangeState("FlippingPendingState");
+    }
+}
+```
+
+---
+
+## 3. Card.cs Extensions
+
+### New Setup Method:
+```csharp
+public class Card
+{
+    /// <summary>
+    /// Setup for album pending placement (starts face-down in corner)
+    /// </summary>
+    public void SetupForAlbumPending()
+    {
+        // Start with NO card data (will be assigned on drag)
+        SetupCard(null, "PendingFaceDownState");
+        SetDraggingEnabled(true); // Enable drag immediately
+    }
+}
+```
+
+### Drag Event Routing:
+```csharp
+// In Card.cs
+public event Action<Card> OnDragStartedEvent;
+
+private void OnDragStarted()
+{
+    OnDragStartedEvent?.Invoke(this);
+}
+```
+
+---
+
+## 4. AlbumViewPage Modifications
+
+### Spawn Pending Cards (Face-Down):
+```csharp
+private void SpawnPendingCards()
+{
+    // Spawn up to 3 "blank" face-down cards in corner
+    for (int i = 0; i < MAX_VISIBLE_CARDS; i++)
+    {
+        GameObject cardObj = Instantiate(cardPrefab, bottomRightSlots.transform);
+        var card = cardObj.GetComponent<StateMachine.Card>();
+        
+        if (card != null)
+        {
+            // Setup as pending (no data yet, face-down)
+            card.SetupForAlbumPending();
+            
+            // Subscribe to drag start
+            card.OnDragStartedEvent += OnCornerCardDragStarted;
+            
+            // Assign to corner slot
+            DraggableSlot slot = FindSlotByIndex(i);
+            card.AssignToSlot(slot, true);
+            
+            _cornerCards.Add(card);
+        }
+    }
+}
+```
+
+### Handle Drag Start (Smart Selection):
+```csharp
+private void OnCornerCardDragStarted(Card cornerCard)
+{
+    if (_pendingQueue.Count == 0) return;
+    
+    // Smart selection logic (from section 2)
+    CardData selectedCard = SelectSmartPendingCard();
+    
+    // Assign data to the dragged corner card
+    cornerCard.Context.SetupCard(selectedCard);
+    
+    // State transition to flipping (handled by state machine)
+    // FlippingPendingState will trigger flip animation + album navigation
+}
+```
+
+### Navigate to Card's Page:
+```csharp
+public void NavigateToCardPage(CardData card)
+{
+    int targetPage = FindPageForCard(card);
+    if (targetPage != _currentAlbumPageIndex)
+    {
+        // Trigger book page flip animation
+        bookController.FlipToPage(targetPage);
+    }
+}
+```
+
+---
+
+## 5. State Implementation Details
+
+### CardPendingFaceDownState.cs
+```csharp
+public class CardPendingFaceDownState : AppleState
+{
+    private CardContext _context;
+    
+    public override void OnEnterState()
+    {
+        // Show card back, hide card front
+        if (_context.CardDisplay != null)
+        {
+            _context.CardDisplay.gameObject.SetActive(false); // Hide front
+        }
+        
+        var cardBack = GetComponentInChildren<CardBack>(); // Assumes CardBack component exists
+        if (cardBack != null)
+        {
+            cardBack.gameObject.SetActive(true);
+        }
+        
+        // Small scale for corner slot
+        _context.RootTransform.localScale = Vector3.one * 0.8f;
+    }
+}
+```
+
+### CardFlippingPendingState.cs
+```csharp
+public class CardFlippingPendingState : AppleState
+{
+    private CardContext _context;
+    
+    public override void OnEnterState()
+    {
+        // Notify album page to navigate
+        var albumPage = FindObjectOfType<AlbumViewPage>();
+        if (albumPage != null)
+        {
+            albumPage.NavigateToCardPage(_context.CardData);
+        }
+        
+        // Play flip animation
+        if (_context.Animator != null)
+        {
+            _context.Animator.PlayFlip(
+                startRotation: Quaternion.Euler(0, 180, 0), // back facing
+                endRotation: Quaternion.identity,           // front facing
+                onComplete: OnFlipComplete
+            );
+        }
+    }
+    
+    private void OnFlipComplete()
+    {
+        _context.StateMachine.ChangeState("DraggingRevealedState");
+    }
+}
+```
+
+### CardDraggingRevealedState.cs
+```csharp
+public class CardDraggingRevealedState : AppleState
+{
+    private CardContext _context;
+    private AlbumCardSlot _hoveredSlot;
+    
+    public override void OnEnterState()
+    {
+        // Card front visible, clean revealed (no badges)
+        if (_context.CardDisplay != null)
+        {
+            _context.CardDisplay.gameObject.SetActive(true);
+        }
+        
+        // Slightly larger while dragging
+        _context.Animator.PlayEnlarge(1.2f);
+    }
+    
+    void Update()
+    {
+        // Detect hover over valid album slots
+        _hoveredSlot = DetectValidSlotUnderCursor();
+        
+        if (_hoveredSlot != null)
+        {
+            // Visual feedback: highlight slot or card
+        }
+    }
+    
+    public void OnDragEnded()
+    {
+        if (_hoveredSlot != null && _hoveredSlot.CanAcceptCard(_context.CardData))
+        {
+            // Snap to slot and transition to PlacedInSlotState
+            SnapToSlot(_hoveredSlot);
+        }
+        else
+        {
+            // Return to corner, flip back to face-down
+            ReturnToCorner();
+        }
+    }
+}
+```
+
+---
+
+## 6. Required New Components
+
+### CardBack Component
+```csharp
+public class CardBack : MonoBehaviour
+{
+    [SerializeField] private Image backImage;
+    
+    public void Show() => gameObject.SetActive(true);
+    public void Hide() => gameObject.SetActive(false);
+}
+```
+
+Attach to Card prefab as a sibling to CardDisplay.
+
+---
+
+## 7. Prefab Structure
+
+```
+Card (GameObject)
+├── StateMachine (AppleMachine)
+│   ├── PendingFaceDownState
+│   ├── FlippingPendingState
+│   ├── DraggingRevealedState
+│   ├── PlacedInSlotState (existing)
+│   └── ... (other states)
+├── CardContext
+├── CardAnimator
+├── CardDisplay (front visuals)
+├── CardBack (back visuals - NEW)
+└── DraggableObject
+```
+
+---
+
+## 8. Migration Steps
+
+### Step 1: Create New States
+- CardPendingFaceDownState.cs
+- CardFlippingPendingState.cs
+- CardDraggingRevealedState.cs
+
+### Step 2: Add CardBack Component
+- Create CardBack.cs script
+- Add CardBack GameObject to Card prefab
+- Design card back visual (sprite, frame, etc.)
+
+### Step 3: Update Card.cs
+- Add SetupForAlbumPending() method
+- Add OnDragStartedEvent
+- Wire drag events to state machine
+
+### Step 4: Update AlbumViewPage
+- Modify SpawnPendingCards() to spawn face-down
+- Implement smart selection logic
+- Add NavigateToCardPage() method
+- Connect to book flip controller
+
+### Step 5: Update CardAnimator
+- Ensure PlayFlip() can handle arbitrary start/end rotations
+- Add any needed drag-follow animation helpers
+
+### Step 6: Testing
+- Test corner card drag → flip → album navigation
+- Test smart selection (page match prioritization)
+- Test return-to-corner on invalid drop
+- Test snap-to-slot on valid drop
+- Test multiple cards in queue
+
+---
+
+## 9. Edge Cases & Considerations
+
+### No Pending Cards
+- Don't spawn corner cards if pending queue is empty
+- Hide corner slots when no cards to place
+
+### Album Page Navigation During Drag
+- Lock page flipping while dragging (prevent user manual flip)
+- Queue navigation if flip animation in progress
+
+### Multiple Cards Dragged Simultaneously
+- Only allow one card to be in FlippingPending/DraggingRevealed at a time
+- Disable other corner cards while one is being dragged
+
+### Card Returns to Corner
+- Flip back animation (reverse of reveal)
+- Re-enter PendingFaceDownState
+- Unassign CardData (become "blank" again for next drag)
+
+### Invalid Slot Drop
+- Visual feedback (shake, red highlight)
+- Smooth return animation to corner
+
+---
+
+## 10. Benefits of This Approach
+
+✅ **Consistent State Architecture** - Uses same state machine pattern as booster flow  
+✅ **Smart UX** - Auto-navigation to correct album page  
+✅ **Clean Separation** - States handle visuals/behavior, page handles logic  
+✅ **Reusable** - States can be reused for other card flows  
+✅ **Extensible** - Easy to add new behaviors (e.g., card preview on hover)  
+✅ **Testable** - Each state can be tested independently  
+
+---
+
+## Open Questions for Approval
+
+1. **Card Back Design:** Should we use a generic back for all cards, or rarity-specific backs?
+2. **Navigation Timing:** Should album flip happen instantly or animated during card flip?
+3. **Return Animation:** Fast snap-back or gentle float-back when invalid drop?
+4. **Multiple Rarities:** If pending queue has same card at multiple rarities, which to prioritize?
+5. **Corner Slot Count:** Keep at 3, or make configurable?
+
+---
+
+Ready to implement once approved! 🎉
+