diff --git a/src/ui/components/card_node.gd b/src/ui/components/card_node.gd
index 40ede0f..0fa23c5 100644
--- a/src/ui/components/card_node.gd
+++ b/src/ui/components/card_node.gd
@@ -25,7 +25,7 @@ func update_display() -> void:
 	var rank_idx := card_data.rank()
 
 	# 构建图片文件名：如 "2H.png", "AS.png", "SJ.png", "BJ.png"
-	var rank_str := RANK_PREFIX[rank_idx]
+	var rank_str: String = RANK_PREFIX[rank_idx]
 	var file_name: String
 	if suit_idx == 4:
 		# 小王
@@ -34,7 +34,7 @@ func update_display() -> void:
 		# 大王
 		file_name = "BJ.png"
 	else:
-		var suit_str := SUIT_LETTER[suit_idx]
+		var suit_str: String = SUIT_LETTER[suit_idx]
 		file_name = "%s%s.png" % [rank_str, suit_str]
 
 	var full_path := CARD_TEXTURE_PATH + file_name