diff --git a/frontend/e2e/auth-shelf.spec.ts b/frontend/e2e/auth-shelf.spec.ts
index 6cc8556..71cd9e8 100644
--- a/frontend/e2e/auth-shelf.spec.ts
+++ b/frontend/e2e/auth-shelf.spec.ts
@@ -51,6 +51,26 @@ test("登录 → 书架 → CBZ 阅读翻页 → 书签 → 退出", async ({ pa
     await expect(page.getByText("2/3")).toBeVisible();
   }).toPass({ timeout: 20_000 });
 
+  // 页模式 + RTL 冒烟:开设置面板 → 单页 → 右缘翻页 → 右开本(RTL) 方向翻转 → 回长卷。
+  await page.getByRole("button", { name: "更多阅读设置" }).click();
+  await page.getByRole("button", { name: "单页" }).click();
+  await expect(page.getByText(/^1\/3 · /)).toBeVisible(); // 模式切换保持当前页:此时在第 2 页
+  // 回到第 1 页:左缘点击
+  const box2 = await reader.boundingBox();
+  if (!box2) throw new Error("阅读器容器无 boundingBox");
+  await page.mouse.click(box2.x + box2.width * 0.1, box2.y + box2.height / 2);
+  await expect(page.getByText(/^1\/3 · /)).toBeVisible();
+  // 右缘点击 → 第 2 页
+  await page.mouse.click(box2.x + box2.width * 0.9, box2.y + box2.height / 2);
+  await expect(page.getByText(/^2\/3 · /)).toBeVisible();
+  // RTL:右缘点击变后退
+  await page.getByRole("button", { name: "右开本(RTL)" }).click();
+  await page.mouse.click(box2.x + box2.width * 0.9, box2.y + box2.height / 2);
+  await expect(page.getByText(/^1\/3 · /)).toBeVisible();
+  // 回长卷
+  await page.getByRole("button", { name: "长卷", exact: true }).click();
+  await expect(page.getByText("1/3")).toBeVisible();
+
   // 导航抽屉(本 fixture 无内嵌目录,抽屉直接落在书签面板)→ 加书签 → toast
   await page.getByRole("button", { name: "导航", exact: true }).click();
   const nav = page.locator("#reader-nav");
diff --git a/frontend/probe-shelf.png b/frontend/probe-shelf.png
new file mode 100644
index 0000000..b9e1441
Binary files /dev/null and b/frontend/probe-shelf.png differ
diff --git a/frontend/src/readers/CbzReader.pagemode.test.tsx b/frontend/src/readers/CbzReader.pagemode.test.tsx
new file mode 100644
index 0000000..0daa24a
--- /dev/null
+++ b/frontend/src/readers/CbzReader.pagemode.test.tsx
@@ -0,0 +1,53 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { fireEvent, render, screen } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { ThemeProvider } from "@/components/theme";
+import CbzReader from "@/readers/CbzReader";
+
+const okResponse = (body: unknown) =>
+  new Response(JSON.stringify(body), { status: 200, headers: { "Content-Type": "application/json" } });
+
+beforeEach(() => {
+  localStorage.clear();
+  vi.restoreAllMocks?.();
+  // 全局网络打桩:页数接口 + 图片对象 URL + 进度上报(页图数据解不真实也无需:PageImg 有占位态)
+  vi.spyOn(globalThis, "fetch").mockImplementation(async (input) => {
+    const url = String(input instanceof Request ? input.url : input);
+    if (url.includes("/pages")) return okResponse({ count: 3, chapters: null });
+    if (url.includes("/progress")) return okResponse(null);
+    return new Response("", { status: 200 }); // 页图 blob 等
+  });
+  Object.defineProperty(URL, "createObjectURL", { value: () => "blob:x", configurable: true });
+});
+
+const book = {
+  id: 1,
+  library_id: 1,
+  path: "p",
+  title: "t",
+  format: "cbz",
+  state: "ok",
+  percent: 0,
+  pages_url: "/pages",
+  page_url_fmt: "/page/{}",
+} as never;
+
+describe("CbzReader 页模式设置区", () => {
+  it("切「单页」后位置读数 1/3,切「双页」首页不变,切回「长卷」按钮仍可用", async () => {
+    render(
+      <ThemeProvider>
+        <QueryClientProvider client={new QueryClient()}>
+          <CbzReader book={book} chrome={{ on: true, toggle: () => {}, show: () => {} }} />
+        </QueryClientProvider>
+      </ThemeProvider>,
+    );
+    await screen.findByLabelText("漫画阅读器,点按左右两侧翻屏,点按中间显示工具栏");
+    fireEvent.click(await screen.findByRole("button", { name: "更多阅读设置" }));
+    fireEvent.click(await screen.findByRole("button", { name: "单页" }));
+    expect(screen.getByText(/^1\/3 · /)).toBeInTheDocument();
+    fireEvent.click(await screen.findByRole("button", { name: "双页" }));
+    expect(screen.getByText(/^1\/3 · /)).toBeInTheDocument();
+    // 模式按钮组仍在设置面板内(长卷收进同一展开区)
+    expect(screen.getByRole("button", { name: "长卷" })).toBeInTheDocument();
+  });
+});
diff --git a/frontend/src/readers/CbzReader.tsx b/frontend/src/readers/CbzReader.tsx
index 8e639a8..22be12d 100644
--- a/frontend/src/readers/CbzReader.tsx
+++ b/frontend/src/readers/CbzReader.tsx
@@ -221,6 +221,8 @@ export default function CbzReader({ book, initialLocator, initialPercent, chrome
     } else {
       scrollToPage(t, false);
     }
+    // 容器重挂后 scrollTop 归 0 且无 scroll 事件可刷 → 手动同步换算用的 top,避免沿用切走前的旧读数
+    setTop(boxRef.current?.scrollTop ?? 0);
   }, [stripSeek, mode]);
 
   useEffect(() => {