diff --git a/wwwroot/api/opp_item_detail.dspy b/wwwroot/api/opp_item_detail.dspy
index 8c85d07..e7bde03 100644
--- a/wwwroot/api/opp_item_detail.dspy
+++ b/wwwroot/api/opp_item_detail.dspy
@@ -154,12 +154,25 @@ else:
 				size_txt = "%.1f MB" % (a_size / 1048576.0)
 			elif a_size > 0:
 				size_txt = "%.0f KB" % (a_size / 1024.0)
-			dl_query = "?tender_id=" + item_id
-			if a_id:
-				dl_query += "&att_id=" + a_id
+			act_btns = []
+			if a.get("downloaded"):
+				# 平台已存副本 → 走代理下载
+				dl_query = "?tender_id=" + item_id
+				if a_id:
+					dl_query += "&att_id=" + a_id
+				elif a_url:
+					dl_query += "&att_url=" + a_url
+				dl_href = dl_base + dl_query
+				act_btns.append({"widgettype": "Button", "options": {"label": "下载", "css": "small"},
+					"binds": [{"wid": "self", "event": "click", "actiontype": "script",
+						"target": "self",
+						"script": "window.location.href=" + _json.dumps(dl_href) + ";"}]})
 			elif a_url:
-				dl_query += "&att_url=" + a_url
-			dl_href = dl_base + dl_query
+				# 平台未存副本（如需登录才能取）→ 如实给原始页入口，不伪装成可下载
+				act_btns.append({"widgettype": "Button", "options": {"label": "打开原始页", "css": "small"},
+					"binds": [{"wid": "self", "event": "click", "actiontype": "script",
+						"target": "self",
+						"script": "window.open(" + _json.dumps(a_url) + ",'_blank','noopener');"}]})
 			body.append({
 				"widgettype": "HBox",
 				"options": {"width": "100%", "gap": "10px", "alignItems": "center",
@@ -171,12 +184,8 @@ else:
 						"wrap": True}},
 					{"widgettype": "Text", "options": {"text": size_txt,
 						"cfontsize": 0.75, "color": "#94a3b8"}},
-					{"widgettype": "Filler"},
-					{"widgettype": "Button", "options": {"label": "下载", "css": "small"},
-						"binds": [{"wid": "self", "event": "click", "actiontype": "script",
-							"target": "self",
-							"script": "window.location.href=" + _json.dumps(dl_href) + ";"}]}
-				]
+					{"widgettype": "Filler"}
+				] + act_btns
 			})
 
 return {