diff --git a/TeleBot/TeleBot/Handlers/CallbackHandler.cs b/TeleBot/TeleBot/Handlers/CallbackHandler.cs
index 8c0e021..b3be7ab 100644
--- a/TeleBot/TeleBot/Handlers/CallbackHandler.cs
+++ b/TeleBot/TeleBot/Handlers/CallbackHandler.cs
@@ -1430,8 +1430,27 @@ namespace TeleBot.Handlers
             var product = await _shopService.GetProductAsync(productId.Value);
             if (product == null) return;
 
-            // For single item, replace selection
-            var selectedVariants = new List<string> { variantName };
+            // Get existing selections
+            var selectedVariants = session.TempData.ContainsKey("selected_variants")
+                ? session.TempData["selected_variants"] as List<string> ?? new List<string>()
+                : new List<string>();
+
+            // Find the variant type for the selected variant
+            var selectedVariantObj = product.Variants?.FirstOrDefault(v => v.Name == variantName);
+            if (selectedVariantObj != null)
+            {
+                // Remove any previous selection from the same variant type
+                var variantsOfSameType = product.Variants
+                    .Where(v => v.VariantType == selectedVariantObj.VariantType)
+                    .Select(v => v.Name)
+                    .ToList();
+
+                selectedVariants.RemoveAll(v => variantsOfSameType.Contains(v));
+
+                // Add the new selection
+                selectedVariants.Add(variantName);
+            }
+
             session.TempData["selected_variants"] = selectedVariants;
 
             var quantity = session.TempData.ContainsKey("current_quantity")