diff --git a/unity-client/Assets/Scripts/UI/CollectionController.cs b/unity-client/Assets/Scripts/UI/CollectionController.cs
new file mode 100644
index 0000000..f020a01
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+++ b/unity-client/Assets/Scripts/UI/CollectionController.cs
@@ -0,0 +1,353 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Text;
+using UnityEngine;
+using UnityEngine.UI;
+using UnityEngine.SceneManagement;
+using TMPro;
+using Newtonsoft.Json;
+using CommanderAILab.Models;
+using CommanderAILab.Services;
+
+namespace CommanderAILab.UI
+{
+  /// <summary>
+  /// Collection scene controller — card grid with search, filter, sort,
+  /// card detail panel, async image loading, pagination, and mobile support.
+  /// </summary>
+  public class CollectionController : MonoBehaviour
+  {
+    // ── Header ──────────────────────────────────────────────────────────
+    [Header("Navigation")]
+    [SerializeField] private Button backButton;
+
+    [Header("Search & Sort")]
+    [SerializeField] private TMP_InputField searchInput;
+    [SerializeField] private TMP_Dropdown  sortDropdown;
+    [SerializeField] private Button        searchButton;
+    [SerializeField] private Button        filterToggleButton;  // mobile: open/close drawer
+
+    [Header("Filter Sidebar")]
+    [SerializeField] private GameObject    filterPanel;         // root – toggled on mobile
+    [SerializeField] private TMP_Dropdown  colorFilterDropdown;
+    [SerializeField] private TMP_Dropdown  typeFilterDropdown;
+    [SerializeField] private TMP_Dropdown  setFilterDropdown;
+    [SerializeField] private TMP_Dropdown  rarityFilterDropdown;
+    [SerializeField] private TMP_Dropdown  ownedFilterDropdown; // All / Owned / Missing
+    [SerializeField] private Button        applyFilterButton;
+    [SerializeField] private Button        clearFilterButton;
+
+    [Header("Card Grid")]
+    [SerializeField] private Transform     cardGridParent;      // ScrollRect content
+    [SerializeField] private GameObject    cardPrefab;          // CardPrefab instance
+    [SerializeField] private ScrollRect    gridScrollRect;
+
+    [Header("Pagination")]
+    [SerializeField] private Button        loadMoreButton;
+    [SerializeField] private TMP_Text      pageInfoText;
+    [SerializeField] private GameObject    loadingSpinner;
+
+    [Header("Card Detail Panel")]
+    [SerializeField] private GameObject    detailPanel;
+    [SerializeField] private Image         detailCardFront;
+    [SerializeField] private Image         detailCardBack;      // placeholder / back face
+    [SerializeField] private TMP_Text      detailCardName;
+    [SerializeField] private TMP_Text      detailManaCost;
+    [SerializeField] private TMP_Text      detailType;
+    [SerializeField] private TMP_Text      detailRarity;
+    [SerializeField] private TMP_Text      detailSet;
+    [SerializeField] private TMP_Text      detailOracleText;
+    [SerializeField] private TMP_Text      detailQuantity;
+    [SerializeField] private Button        detailAddToDeckButton;
+    [SerializeField] private Button        detailCloseButton;
+
+    [Header("Error")]
+    [SerializeField] private GameObject    errorPanel;
+    [SerializeField] private TMP_Text      errorText;
+    [SerializeField] private Button        retryButton;
+
+    // ── State ────────────────────────────────────────────────────────────
+    private List<CardModel> _cards       = new();
+    private CardModel       _selectedCard;
+    private int             _currentPage = 1;
+    private int             _totalCards  = 0;
+    private const int       PageSize     = 40;
+    private bool            _isLoading   = false;
+    private bool            _filterOpen  = false;
+
+    // Current filter / sort state
+    private string _searchQuery   = "";
+    private string _colorFilter   = "";
+    private string _typeFilter    = "";
+    private string _setFilter     = "";
+    private string _rarityFilter  = "";
+    private string _ownedFilter   = "";   // "all" | "owned" | "missing"
+    private string _sortField     = "name";
+
+    // Pooled card tile GameObjects
+    private readonly List<GameObject> _cardTiles = new();
+
+    // ── Lifecycle ────────────────────────────────────────────────────────
+    private void Start()
+    {
+      // Back button → MainMenu
+      backButton.onClick.AddListener(() => SceneManager.LoadScene("MainMenu"));
+
+      // Search
+      searchButton.onClick.AddListener(OnSearchClicked);
+      searchInput.onSubmit.AddListener(_ => OnSearchClicked());
+
+      // Sort
+      sortDropdown.onValueChanged.AddListener(_ => RefreshFromPage1());
+
+      // Filter actions
+      applyFilterButton.onClick.AddListener(RefreshFromPage1);
+      clearFilterButton.onClick.AddListener(OnClearFilters);
+      filterToggleButton.onClick.AddListener(ToggleFilterPanel);
+
+      // Pagination
+      loadMoreButton.onClick.AddListener(OnLoadMore);
+      loadMoreButton.gameObject.SetActive(false);
+
+      // Detail panel
+      detailCloseButton.onClick.AddListener(CloseDetailPanel);
+      detailAddToDeckButton.onClick.AddListener(OnAddToDeck);
+      detailPanel.SetActive(false);
+
+      // Error retry
+      retryButton.onClick.AddListener(RefreshFromPage1);
+      errorPanel.SetActive(false);
+
+      // On mobile start with filter panel hidden
+      _filterOpen = Screen.width > 900;
+      filterPanel.SetActive(_filterOpen);
+
+      // Initial load
+      RefreshFromPage1();
+    }
+
+    // ── Search / Filter / Sort ───────────────────────────────────────────
+    private void OnSearchClicked()
+    {
+      _searchQuery = searchInput.text.Trim();
+      RefreshFromPage1();
+    }
+
+    private void OnClearFilters()
+    {
+      colorFilterDropdown.value  = 0;
+      typeFilterDropdown.value   = 0;
+      setFilterDropdown.value    = 0;
+      rarityFilterDropdown.value = 0;
+      ownedFilterDropdown.value  = 0;
+      searchInput.text           = "";
+      _searchQuery               = "";
+      RefreshFromPage1();
+    }
+
+    private void ToggleFilterPanel()
+    {
+      _filterOpen = !_filterOpen;
+      filterPanel.SetActive(_filterOpen);
+    }
+
+    // ── Data Loading ─────────────────────────────────────────────────────
+    private void RefreshFromPage1()
+    {
+      _currentPage = 1;
+      _cards.Clear();
+      ClearCardTiles();
+      LoadPage(_currentPage);
+    }
+
+    private void OnLoadMore()
+    {
+      _currentPage++;
+      LoadPage(_currentPage);
+    }
+
+    private void LoadPage(int page)
+    {
+      if (_isLoading) return;
+      _isLoading = true;
+      loadingSpinner.SetActive(true);
+      loadMoreButton.interactable = false;
+      errorPanel.SetActive(false);
+
+      // Collect filter values from dropdowns
+      _colorFilter  = DropdownValue(colorFilterDropdown);
+      _typeFilter   = DropdownValue(typeFilterDropdown);
+      _setFilter    = DropdownValue(setFilterDropdown);
+      _rarityFilter = DropdownValue(rarityFilterDropdown);
+      _ownedFilter  = DropdownValue(ownedFilterDropdown);
+      _sortField    = SortFieldFromDropdown(sortDropdown.value);
+
+      string path = BuildQueryPath(page);
+      StartCoroutine(ApiClient.Instance.GetRaw(path,
+        json    => OnPageLoaded(json, page),
+        errMsg  => OnLoadError(errMsg)));
+    }
+
+    private string BuildQueryPath(int page)
+    {
+      var sb = new StringBuilder("/api/collection?");
+      sb.Append($"page={page}&per_page={PageSize}");
+      if (!string.IsNullOrEmpty(_searchQuery))
+        sb.Append($"&search={UnityWebRequest.EscapeURL(_searchQuery)}");
+      if (!string.IsNullOrEmpty(_colorFilter))
+        sb.Append($"&colors={UnityWebRequest.EscapeURL(_colorFilter)}");
+      if (!string.IsNullOrEmpty(_typeFilter))
+        sb.Append($"&type={UnityWebRequest.EscapeURL(_typeFilter)}");
+      if (!string.IsNullOrEmpty(_setFilter))
+        sb.Append($"&set={UnityWebRequest.EscapeURL(_setFilter)}");
+      if (!string.IsNullOrEmpty(_rarityFilter))
+        sb.Append($"&rarity={UnityWebRequest.EscapeURL(_rarityFilter)}");
+      if (!string.IsNullOrEmpty(_ownedFilter) && _ownedFilter != "all")
+        sb.Append($"&owned={_ownedFilter}");
+      if (!string.IsNullOrEmpty(_sortField))
+        sb.Append($"&sort={_sortField}");
+      return sb.ToString();
+    }
+
+    private void OnPageLoaded(string json, int page)
+    {
+      _isLoading = false;
+      loadingSpinner.SetActive(false);
+
+      CollectionResponse response;
+      try { response = JsonConvert.DeserializeObject<CollectionResponse>(json); }
+      catch (Exception e)
+      {
+        OnLoadError($"Parse error: {e.Message}");
+        return;
+      }
+
+      _totalCards = response.total;
+      _cards.AddRange(response.cards);
+
+      UpdatePageInfo();
+      SpawnCardTiles(response.cards);
+
+      bool hasMore = _cards.Count < _totalCards;
+      loadMoreButton.gameObject.SetActive(hasMore);
+      loadMoreButton.interactable = true;
+    }
+
+    private void OnLoadError(string msg)
+    {
+      _isLoading = false;
+      loadingSpinner.SetActive(false);
+      errorText.text = $"Failed to load collection:\n{msg}";
+      errorPanel.SetActive(true);
+      Debug.LogWarning($"[CollectionController] {msg}");
+    }
+
+    // ── Card Tiles ───────────────────────────────────────────────────────
+    private void SpawnCardTiles(List<CardModel> cards)
+    {
+      foreach (var card in cards)
+      {
+        var tile = Instantiate(cardPrefab, cardGridParent);
+        _cardTiles.Add(tile);
+
+        // Set name label (assumes CardPrefab has a TMP child named "CardName")
+        var nameLabel = tile.GetComponentInChildren<TMP_Text>();
+        if (nameLabel != null) nameLabel.text = card.name;
+
+        // Async image load
+        var img = tile.GetComponentInChildren<Image>();
+        if (img != null && !string.IsNullOrEmpty(card.imageUrl))
+        {
+          ImageCache.Instance.GetSprite(card.imageUrl, sprite =>
+          {
+            if (img != null) img.sprite = sprite;
+          });
+        }
+
+        // Click → open detail panel
+        var btn = tile.GetComponentInChildren<Button>();
+        if (btn != null)
+        {
+          var captured = card;
+          btn.onClick.AddListener(() => OpenDetailPanel(captured));
+        }
+      }
+    }
+
+    private void ClearCardTiles()
+    {
+      foreach (var tile in _cardTiles)
+        if (tile != null) Destroy(tile);
+      _cardTiles.Clear();
+    }
+
+    // ── Detail Panel ─────────────────────────────────────────────────────
+    private void OpenDetailPanel(CardModel card)
+    {
+      _selectedCard = card;
+      detailPanel.SetActive(true);
+
+      detailCardName.text  = card.name;
+      detailManaCost.text  = card.manaCost;
+      detailType.text      = card.typeLine;
+      detailRarity.text    = card.rarity;
+      detailSet.text       = card.set;
+      detailOracleText.text = card.oracleText;
+      detailQuantity.text  = $"Owned: {card.ownedQty}";
+
+      // Load card art on front face
+      if (!string.IsNullOrEmpty(card.imageUrl))
+      {
+        ImageCache.Instance.GetSprite(card.imageUrl, sprite =>
+        {
+          if (detailCardFront != null) detailCardFront.sprite = sprite;
+        });
+      }
+
+      // Trigger flip animation if the card has an Animator
+      var anim = detailPanel.GetComponentInChildren<Animator>();
+      anim?.SetTrigger("Flip");
+    }
+
+    private void CloseDetailPanel()
+    {
+      detailPanel.SetActive(false);
+      _selectedCard = null;
+    }
+
+    // ── Add to Deck ───────────────────────────────────────────────────────
+    private void OnAddToDeck()
+    {
+      if (_selectedCard == null) return;
+      // Store selected card in PlayerPrefs for DeckBuilder to pick up
+      PlayerPrefs.SetString("PendingAddCard", JsonConvert.SerializeObject(_selectedCard));
+      PlayerPrefs.Save();
+      SceneManager.LoadScene("DeckBuilder");
+    }
+
+    // ── Helpers ───────────────────────────────────────────────────────────
+    private void UpdatePageInfo()
+    {
+      int showing = Mathf.Min(_cards.Count, _totalCards);
+      pageInfoText.text = $"Showing {showing} of {_totalCards} cards";
+    }
+
+    /// <summary>Returns the option text at index 0 as empty string (means no filter).</summary>
+    private static string DropdownValue(TMP_Dropdown dd)
+    {
+      if (dd.value == 0) return "";
+      return dd.options[dd.value].text;
+    }
+
+    private static string SortFieldFromDropdown(int idx) => idx switch
+    {
+      0 => "name",
+      1 => "cmc",
+      2 => "color",
+      3 => "type",
+      4 => "price",
+      _ => "name"
+    };
+  }
+}