diff --git a/src/app/chat/components/pwa-install-overlay.tsx b/src/app/chat/components/pwa-install-overlay.tsx
index 818db4de..1bc551d9 100644
--- a/src/app/chat/components/pwa-install-overlay.tsx
+++ b/src/app/chat/components/pwa-install-overlay.tsx
@@ -19,7 +19,7 @@ import {
   canShowPwaInstallPromptOnce,
   recordPwaInstallPromptShown,
 } from "@/lib/chat/pwa_install_prompt";
-import { BrowserDetector, pwaUtil } from "@/utils";
+import { pwaUtil } from "@/utils";
 
 import { PwaInstallDialog } from "./pwa-install-dialog";
 import styles from "./pwa-install-overlay.module.css";
@@ -37,29 +37,39 @@ export function PwaInstallOverlay({ enabled }: PwaInstallOverlayProps) {
 
     let mounted = true;
     let timer: number | undefined;
+    let unsubscribe: (() => void) | undefined;
 
     const init = async () => {
       // const isDev = AppEnvUtil.isDevelopment();
       const isDev = false;
-      const shouldShowDialog = await shouldShowPwaInstallDialog(isDev);
-      if (!shouldShowDialog) return;
 
       // 提前挂 beforeinstallprompt 监听，避免用户点 OK 时事件已在更早时机丢失。
       pwaUtil.prepareInstallPrompt();
 
-      // 达到聊天数量阈值后稍作停顿，避免弹窗与消息刷新挤在同一瞬间。
-      const delay = isDev
-        ? DEVELOPMENT_DIALOG_DELAY_MS
-        : PRODUCTION_DIALOG_DELAY_MS;
-      timer = window.setTimeout(() => {
-        if (!mounted) return;
-        showPwaDialog();
-      }, delay);
+      const tryScheduleDialog = async () => {
+        const shouldShowDialog = await shouldShowPwaInstallDialog(isDev);
+        if (!mounted || !shouldShowDialog || timer !== undefined) return;
+
+        // 达到聊天数量阈值后稍作停顿，避免弹窗与消息刷新挤在同一瞬间。
+        const delay = isDev
+          ? DEVELOPMENT_DIALOG_DELAY_MS
+          : PRODUCTION_DIALOG_DELAY_MS;
+        timer = window.setTimeout(() => {
+          if (!mounted) return;
+          showPwaDialog();
+        }, delay);
+      };
+
+      await tryScheduleDialog();
+      unsubscribe = pwaUtil.subscribe(() => {
+        void tryScheduleDialog();
+      });
     };
 
     void init();
     return () => {
       mounted = false;
+      unsubscribe?.();
       if (timer !== undefined) window.clearTimeout(timer);
     };
   }, [enabled]);
@@ -69,9 +79,7 @@ export function PwaInstallOverlay({ enabled }: PwaInstallOverlayProps) {
 
 async function shouldShowPwaInstallDialog(isDevelopment: boolean) {
   // PWA 支持 / 安装 双重门禁（两种环境都检查）。
-  if (!pwaUtil.isSupported()) return false;
-  if (pwaUtil.isInstalled()) return false;
-  if (BrowserDetector.isInAppBrowser()) return false;
+  if (!pwaUtil.canShowInstallEntry()) return false;
 
   // 开发环境：跳过"只弹一次"门禁，每次进入都弹，方便 UI 测试。
   if (isDevelopment) return true;
diff --git a/src/app/sidebar/sidebar-screen.tsx b/src/app/sidebar/sidebar-screen.tsx
index 87c0a518..dca25a19 100644
--- a/src/app/sidebar/sidebar-screen.tsx
+++ b/src/app/sidebar/sidebar-screen.tsx
@@ -43,22 +43,27 @@ export function SidebarScreen() {
   ]);
 
   useEffect(() => {
+    const updateInstallEntryVisibility = () => {
+      setCanShowInstallApp(pwaUtil.canShowInstallEntry());
+    };
+
     pwaUtil.prepareInstallPrompt();
-    const timer = window.setTimeout(() => {
-      setCanShowInstallApp(pwaUtil.isSupported() && !pwaUtil.isInstalled());
-    }, 0);
+    updateInstallEntryVisibility();
+    const unsubscribe = pwaUtil.subscribe(updateInstallEntryVisibility);
 
     return () => {
-      window.clearTimeout(timer);
+      unsubscribe();
     };
   }, []);
 
   const handleInstallAppClick = async () => {
     pwaUtil.prepareInstallPrompt();
     const result = await pwaUtil.install();
-    if (result === "accepted" || pwaUtil.isInstalled()) {
-      setCanShowInstallApp(false);
-    }
+    setCanShowInstallApp(
+      result !== "accepted" &&
+        !pwaUtil.isInstalled() &&
+        pwaUtil.canShowInstallEntry(),
+    );
   };
 
   const handleLogoutClick = () => {
diff --git a/src/utils/__tests__/pwa.test.ts b/src/utils/__tests__/pwa.test.ts
new file mode 100644
index 00000000..39646fde
--- /dev/null
+++ b/src/utils/__tests__/pwa.test.ts
@@ -0,0 +1,172 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+import { PwaUtil } from "../pwa";
+
+const ANDROID_CHROME_UA =
+  "Mozilla/5.0 (Linux; Android 14; Pixel 8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Mobile Safari/537.36";
+const ANDROID_FACEBOOK_UA =
+  "Mozilla/5.0 (Linux; Android 14; Pixel 8) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/126.0.0.0 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/566.0.0.48.73;]";
+const ANDROID_SAMSUNG_UA =
+  "Mozilla/5.0 (Linux; Android 14; SM-S928B) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/26.0 Chrome/122.0.0.0 Mobile Safari/537.36";
+const IOS_SAFARI_UA =
+  "Mozilla/5.0 (iPhone; CPU iPhone OS 17_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.5 Mobile/15E148 Safari/604.1";
+const DESKTOP_CHROME_UA =
+  "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36";
+const DESKTOP_FIREFOX_UA =
+  "Mozilla/5.0 (Macintosh; Intel Mac OS X 14.5; rv:126.0) Gecko/20100101 Firefox/126.0";
+
+describe("PwaUtil", () => {
+  beforeEach(() => {
+    setUserAgent(DESKTOP_CHROME_UA);
+    setServiceWorkerSupported(true);
+    setStandalone(false);
+  });
+
+  it("supports native install prompt on desktop Chrome", () => {
+    setUserAgent(DESKTOP_CHROME_UA);
+
+    expect(new PwaUtil().isSupported()).toBe(true);
+  });
+
+  it("supports native install prompt on Android Chrome", () => {
+    setUserAgent(ANDROID_CHROME_UA);
+
+    expect(new PwaUtil().isSupported()).toBe(true);
+  });
+
+  it("supports native install prompt on Samsung Internet", () => {
+    setUserAgent(ANDROID_SAMSUNG_UA);
+
+    expect(new PwaUtil().isSupported()).toBe(true);
+  });
+
+  it("does not support native install prompt on iOS Safari", () => {
+    setUserAgent(IOS_SAFARI_UA);
+
+    expect(new PwaUtil().isSupported()).toBe(false);
+  });
+
+  it("does not support install prompt in Facebook in-app browser", () => {
+    setUserAgent(ANDROID_FACEBOOK_UA);
+
+    expect(new PwaUtil().isSupported()).toBe(false);
+  });
+
+  it("does not support native install prompt on desktop Firefox", () => {
+    setUserAgent(DESKTOP_FIREFOX_UA);
+
+    expect(new PwaUtil().isSupported()).toBe(false);
+  });
+
+  it("does not show install entry before beforeinstallprompt is captured", () => {
+    const util = new PwaUtil();
+    util.prepareInstallPrompt();
+
+    expect(util.canShowInstallEntry()).toBe(false);
+  });
+
+  it("shows install entry after beforeinstallprompt is captured", () => {
+    const util = new PwaUtil();
+    const listener = vi.fn();
+    util.subscribe(listener);
+    util.prepareInstallPrompt();
+
+    dispatchBeforeInstallPrompt();
+
+    expect(listener).toHaveBeenCalledTimes(1);
+    expect(util.canShowInstallEntry()).toBe(true);
+  });
+
+  it("does not show install entry when already installed", () => {
+    const util = new PwaUtil();
+    setStandalone(true);
+    util.prepareInstallPrompt();
+
+    dispatchBeforeInstallPrompt();
+
+    expect(util.canShowInstallEntry()).toBe(false);
+  });
+
+  it("prompts native install when a deferred event is available", async () => {
+    const util = new PwaUtil();
+    const prompt = vi.fn().mockResolvedValue(undefined);
+    util.prepareInstallPrompt();
+    dispatchBeforeInstallPrompt({
+      prompt,
+      outcome: "accepted",
+    });
+
+    await expect(util.install()).resolves.toBe("accepted");
+    expect(prompt).toHaveBeenCalledTimes(1);
+    expect(util.canShowInstallEntry()).toBe(false);
+  });
+
+  it("returns unavailable when no deferred prompt is available", async () => {
+    const util = new PwaUtil();
+    util.prepareInstallPrompt();
+
+    await expect(util.install()).resolves.toBe("unavailable");
+  });
+});
+
+function setUserAgent(userAgent: string): void {
+  Object.defineProperty(window.navigator, "userAgent", {
+    value: userAgent,
+    configurable: true,
+  });
+}
+
+function setServiceWorkerSupported(supported: boolean): void {
+  if (supported) {
+    Object.defineProperty(window.navigator, "serviceWorker", {
+      value: {},
+      configurable: true,
+    });
+    return;
+  }
+
+  Object.defineProperty(window.navigator, "serviceWorker", {
+    value: undefined,
+    configurable: true,
+  });
+}
+
+function setStandalone(installed: boolean): void {
+  Object.defineProperty(window, "matchMedia", {
+    value: vi.fn().mockImplementation((query: string) => ({
+      matches: installed && query === "(display-mode: standalone)",
+      media: query,
+      onchange: null,
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+      addListener: vi.fn(),
+      removeListener: vi.fn(),
+      dispatchEvent: vi.fn(),
+    })),
+    configurable: true,
+  });
+
+  Object.defineProperty(window.navigator, "standalone", {
+    value: installed,
+    configurable: true,
+  });
+}
+
+function dispatchBeforeInstallPrompt({
+  prompt = vi.fn().mockResolvedValue(undefined),
+  outcome = "dismissed",
+}: {
+  prompt?: () => Promise<void>;
+  outcome?: "accepted" | "dismissed";
+} = {}): void {
+  const event = new Event("beforeinstallprompt", {
+    cancelable: true,
+  }) as Event & {
+    prompt: () => Promise<void>;
+    userChoice: Promise<{ outcome: "accepted" | "dismissed" }>;
+  };
+  event.prompt = prompt;
+  event.userChoice = Promise.resolve({ outcome });
+
+  window.dispatchEvent(event);
+}
diff --git a/src/utils/browser-detect.ts b/src/utils/browser-detect.ts
index 3e814c2e..40ed6bdb 100644
--- a/src/utils/browser-detect.ts
+++ b/src/utils/browser-detect.ts
@@ -67,6 +67,16 @@ export class BrowserDetector {
     return /Edge/i.test(BrowserDetector.getBrowserName(ua));
   }
 
+  static isOpera(ua: string | null = null): boolean {
+    const target = `${BrowserDetector.getBrowserName(ua)} ${BrowserDetector.getUserAgent(ua)}`;
+    return /Opera|OPR/i.test(target);
+  }
+
+  static isSamsungInternet(ua: string | null = null): boolean {
+    const target = `${BrowserDetector.getBrowserName(ua)} ${BrowserDetector.getUserAgent(ua)}`;
+    return /Samsung|SamsungBrowser/i.test(target);
+  }
+
   /** 当前是否在 Facebook 内嵌浏览器 */
   static isFacebookInAppBrowser(ua: string | null = null): boolean {
     return /FBAN|FBAV|FB_IAB|FB4A|FBIOS/i.test(BrowserDetector.getUserAgent(ua));
diff --git a/src/utils/pwa.ts b/src/utils/pwa.ts
index 99658b63..7adc96dc 100644
--- a/src/utils/pwa.ts
+++ b/src/utils/pwa.ts
@@ -4,17 +4,17 @@
  *
  * 设计要点：
  *   - SSR 安全：所有方法 `typeof window === "undefined"` 守卫，SSR 全部返 false / "unavailable"
- *   - 内部缓存 `beforeinstallprompt` 事件对象；install() 时如有缓存直接 prompt，否则等
- *     事件触发（带超时），超时未到则返 "unavailable"
+ *   - 只支持可触发原生 `beforeinstallprompt` 的平台 / 浏览器组合
+ *   - 内部缓存 `beforeinstallprompt` 事件对象；install() 时没有缓存则直接返 "unavailable"
  *   - install() 用完一次 deferred 后清空 —— 同一事件只能 prompt 一次（浏览器规范）
- *   - 与 `usePwaInstall` hook 并存：hook 用于 React 组件内部监听 state，
- *     本 util 用于业务逻辑（如 ChatArea 想自动触发安装）—— 两者不冲突
  *
- * 已知浏览器差异（2026/06）：
- *   - iOS Safari: 不发 `beforeinstallprompt`，需用户手动 Share → Add to Home Screen，
- *     本 util 在 iOS 上 isSupported()=true 但 install() 永远返 "unavailable"
- *   - 已安装的 PWA: 浏览器不发 `beforeinstallprompt`，isInstalled() 走 standalone 检测
+ * 浏览器白名单对齐 Flutter 侧 pwa_utils.dart：
+ *   - Desktop: Chrome, Edge, Opera
+ *   - Mobile: Android Chrome, Android Opera, Samsung Internet
+ *   - 应用内浏览器 / WebView 不展示安装入口
  */
+import { BrowserDetector } from "./browser-detect";
+import { PlatformDetector } from "./platform-detect";
 
 // `beforeinstallprompt` 事件 —— 浏览器非标准但主流都支持。
 // 类型参考 MDN: https://developer.mozilla.org/en-US/docs/Web/API/BeforeInstallPromptEvent
@@ -23,27 +23,56 @@ interface BeforeInstallPromptEvent extends Event {
   userChoice: Promise<{ outcome: "accepted" | "dismissed" }>;
 }
 
-/** install() 等待 beforeinstallprompt 事件的最大时长（ms） */
-const BEFORE_INSTALL_PROMPT_TIMEOUT_MS = 3000;
+type PwaInstallListener = () => void;
 
 export class PwaUtil {
   // 模块级状态（单例内）—— 跨多次 install() 调用共享
   private deferred: BeforeInstallPromptEvent | null = null;
   private listenersAttached = false;
+  private readonly listeners = new Set<PwaInstallListener>();
 
   // ===== 公共 API =====
 
   /**
-   * 检查当前浏览器环境是否支持 PWA 安装。
-   *
-   * 判定：存在 `window.navigator.serviceWorker`。
-   * 注意：这只是"能力"层面的检测；具体能否触发安装还取决于 manifest、
-   * HTTPS 上下文、用户参与度（30s+ 互动）等因素 —— 这些由 `install()` 处理。
+   * 当前环境是否支持 Web 原生 PWA 安装提示。
+   * 注意：这里判断的是平台 / 浏览器 / IAB 能力，不代表当前已经拿到 prompt 事件。
    */
   isSupported(): boolean {
     if (typeof window === "undefined") return false;
     if (typeof navigator === "undefined") return false;
-    return "serviceWorker" in navigator;
+    if (!("serviceWorker" in navigator)) return false;
+    if (BrowserDetector.isInAppBrowser()) return false;
+    return this.isBrowserSupported();
+  }
+
+  /**
+   * 当前浏览器是否位于原生安装提示白名单。
+   *
+   * 对齐 Flutter 侧逻辑：
+   * - Desktop: Chrome, Edge, Opera
+   * - Mobile: Android Chrome, Android Opera, Samsung Internet
+   */
+  isBrowserSupported(): boolean {
+    if (typeof window === "undefined") return false;
+    const platform = PlatformDetector.getPlatformInfo();
+
+    if (platform.isDesktop) {
+      return (
+        BrowserDetector.isChrome() ||
+        BrowserDetector.isEdge() ||
+        BrowserDetector.isOpera()
+      );
+    }
+
+    if (platform.isMobile && platform.isAndroid) {
+      return (
+        BrowserDetector.isChrome() ||
+        BrowserDetector.isOpera() ||
+        BrowserDetector.isSamsungInternet()
+      );
+    }
+
+    return false;
   }
 
   /**
@@ -57,6 +86,7 @@ export class PwaUtil {
    */
   isInstalled(): boolean {
     if (typeof window === "undefined") return false;
+    if (typeof navigator === "undefined") return false;
 
     // Android / Chrome / Edge: display-mode media query
     if (
@@ -75,6 +105,19 @@ export class PwaUtil {
     return false;
   }
 
+  /** UI 是否应该展示“安装应用”入口。 */
+  canShowInstallEntry(): boolean {
+    return this.isSupported() && !this.isInstalled() && this.deferred !== null;
+  }
+
+  /** 监听 beforeinstallprompt 捕获 / 安装状态变化，用于 UI 刷新安装入口展示状态。 */
+  subscribe(listener: PwaInstallListener): () => void {
+    this.listeners.add(listener);
+    return () => {
+      this.listeners.delete(listener);
+    };
+  }
+
   /**
    * 提前挂上 `beforeinstallprompt` 监听。
    *
@@ -82,15 +125,17 @@ export class PwaUtil {
    * 很容易错过那次事件，导致后续 `install()` 拿不到 deferred prompt。
    */
   prepareInstallPrompt(): void {
-    if (!this.isSupported()) return;
+    if (!this.isSupported()) {
+      this.clearDeferred();
+      return;
+    }
+    if (this.isInstalled()) {
+      this.clearDeferred();
+      return;
+    }
     this.attachListener();
   }
 
-  /** 当前是否已缓存可用的原生安装提示事件。 */
-  canPromptInstall(): boolean {
-    return this.deferred !== null;
-  }
-
   /**
    * 触发 PWA 安装（浏览器原生安装提示）。
    *
@@ -103,7 +148,7 @@ export class PwaUtil {
    *   1) 不支持 / 已安装 → 直接返 "unavailable"
    *   2) 挂 beforeinstallprompt 监听（懒初始化，挂一次）
    *   3) 如已有 deferred 事件 → 直接 prompt
-   *   4) 否则等最多 BEFORE_INSTALL_PROMPT_TIMEOUT_MS，事件到了再 prompt
+   *   4) 否则返 "unavailable"，由 UI 等下一次 beforeinstallprompt 通知后再展示入口
    *   5) 用完一次 deferred 清空（浏览器规范：同一事件只能 prompt 一次）
    */
   async install(): Promise<"accepted" | "dismissed" | "unavailable"> {
@@ -117,15 +162,9 @@ export class PwaUtil {
     // 挂监听（首次 install() 调用时挂上；之后重复调用复用同一 listener）
     this.attachListener();
 
-    // 如已有缓存的 deferred 直接用；否则等事件触发
-    if (!this.deferred) {
-      const got = await this.waitForDeferred();
-      if (!got) return "unavailable";
-    }
-
     const deferred = this.deferred;
     if (!deferred) return "unavailable";
-    this.deferred = null; // 一次性 —— 浏览器规范：同一事件只能 prompt 一次
+    this.clearDeferred(); // 一次性 —— 浏览器规范：同一事件只能 prompt 一次
 
     try {
       await deferred.prompt();
@@ -148,36 +187,30 @@ export class PwaUtil {
     if (typeof window === "undefined") return;
 
     const handler = (e: Event) => {
-      // 阻止浏览器默认行为（让应用自己决定何时 prompt）
+      // 阻止浏览器默认行为（让应用自己决定何时 prompt）。
       e.preventDefault();
+
+      if (!this.isSupported() || this.isInstalled()) {
+        this.clearDeferred();
+        return;
+      }
       this.deferred = e as BeforeInstallPromptEvent;
+      this.notifyListeners();
     };
     window.addEventListener("beforeinstallprompt", handler);
     this.listenersAttached = true;
   }
 
-  /**
-   * 轮询等待 deferred 事件就绪（带超时）
-   * - 100ms 间隔轮询，足够响应且不阻塞主线程
-   * - 超时返 false —— 调用方走 "unavailable" 兜底
-   */
-  private waitForDeferred(timeoutMs: number = BEFORE_INSTALL_PROMPT_TIMEOUT_MS): Promise<boolean> {
-    return new Promise((resolve) => {
-      const start = Date.now();
-      const tick = () => {
-        if (this.deferred) {
-          resolve(true);
-          return;
-        }
-        if (Date.now() - start > timeoutMs) {
-          resolve(false);
-          return;
-        }
-        setTimeout(tick, 100);
-      };
-      tick();
-    });
+  private clearDeferred(): void {
+    if (this.deferred === null) return;
+    this.deferred = null;
+    this.notifyListeners();
   }
+
+  private notifyListeners(): void {
+    this.listeners.forEach((listener) => listener());
+  }
+
 }
 
 /** 全局单例（与 `deviceIdentifier` / `SpAsyncUtil` 命名约定一致） */