diff --git a/app/tool/browser.py b/app/tool/browser.py
index 81815f8..f56a677 100644
--- a/app/tool/browser.py
+++ b/app/tool/browser.py
@@ -30,6 +30,19 @@ _GOTO_TIMEOUT = 30000
 #   --disable-dev-shm-usage 容器 /dev/shm 偏小时改用磁盘，避免渲染进程崩溃
 _LAUNCH_ARGS = ["--no-sandbox", "--disable-dev-shm-usage"]
 
+# 浏览器上下文固定参数：不显式指定的话，UA 会跟着宿主系统变
+# （Windows 开发机是 Windows UA，Linux 容器是 X11 UA），目标站会按 UA 返回不同页面模板，
+# 导致同一套选择器在容器里全部落空
+_CONTEXT_OPTIONS: dict[str, Any] = {
+    "user_agent": (
+        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
+        "(KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
+    ),
+    "viewport": {"width": 1920, "height": 1080},
+    "locale": "zh-CN",
+    "timezone_id": "Asia/Shanghai",
+}
+
 
 @dataclass
 class NodeSnapshot:
@@ -214,7 +227,7 @@ class _BrowserRuntime:
 
     async def _open_page_impl(self, url: str, wait_ms: int) -> str:
         browser = await self._ensure_browser()
-        context = await browser.new_context()
+        context = await browser.new_context(**_CONTEXT_OPTIONS)
         page = await context.new_page()
 
         try: