diff --git a/frontend-web/src/App.tsx b/frontend-web/src/App.tsx
index a4a67c48..0235b013 100644
--- a/frontend-web/src/App.tsx
+++ b/frontend-web/src/App.tsx
@@ -61,7 +61,10 @@ function AppProviders({ children }: { children: React.ReactNode }) {
     // 走 next-themes forcedTheme（不写 localStorage）→ 同浏览器另开的正常系统页不受影响。
     const embedTheme = resolveForcedEmbedTheme(location.search);
     if (embedTheme) return embedTheme;
-    const routeTheme = resolveForcedThemeForPath(location.pathname);
+    const routeTheme = resolveForcedThemeForPath(
+      location.pathname,
+      location.search,
+    );
     if (routeTheme) return routeTheme;
     if (location.pathname === "/embed/roundtable") {
       const wp = readWujieProps();
diff --git a/frontend-web/src/core/page-layout/chats-iframe-route.test.mjs b/frontend-web/src/core/page-layout/chats-iframe-route.test.mjs
index eefe33b2..5cdb649b 100644
--- a/frontend-web/src/core/page-layout/chats-iframe-route.test.mjs
+++ b/frontend-web/src/core/page-layout/chats-iframe-route.test.mjs
@@ -31,3 +31,20 @@ test("forces light theme for landing and chats_iframe routes only", () => {
   );
   assert.equal(resolveForcedThemeForPath("/page/workspace/chats/new"), undefined);
 });
+
+test("honors the dark-blue theme query on chats_iframe routes", () => {
+  assert.equal(
+    resolveForcedThemeForPath(
+      "/page/workspace/chats_iframe/new",
+      "?from=iframe&theme=dark-blue",
+    ),
+    "dark",
+  );
+  assert.equal(
+    resolveForcedThemeForPath(
+      "/page/workspace/chats_iframe/new",
+      "?from=iframe&theme=red",
+    ),
+    "light",
+  );
+});
diff --git a/frontend-web/src/core/page-layout/chats-iframe-route.ts b/frontend-web/src/core/page-layout/chats-iframe-route.ts
index 30c6ba78..06b13117 100644
--- a/frontend-web/src/core/page-layout/chats-iframe-route.ts
+++ b/frontend-web/src/core/page-layout/chats-iframe-route.ts
@@ -1,3 +1,5 @@
+import { resolveEmbedThemeMode } from "@/core/embed/embed-session";
+
 export function isChatsIframeWorkspacePath(pathname: string): boolean {
   return (
     pathname === "/page/workspace/chats_iframe/new" ||
@@ -7,10 +9,17 @@ export function isChatsIframeWorkspacePath(pathname: string): boolean {
 
 export function resolveForcedThemeForPath(
   pathname: string,
-): "light" | undefined {
-  if (pathname === "/landing" || isChatsIframeWorkspacePath(pathname)) {
+  search = "",
+): "light" | "dark" | undefined {
+  if (pathname === "/landing") {
     return "light";
   }
 
+  if (isChatsIframeWorkspacePath(pathname)) {
+    const normalizedSearch = search.startsWith("?") ? search : `?${search}`;
+    const rawTheme = new URLSearchParams(normalizedSearch).get("theme")?.trim();
+    return rawTheme ? resolveEmbedThemeMode(rawTheme) : "light";
+  }
+
   return undefined;
 }