diff --git a/app/globals.css b/app/globals.css
index 2b5246e..20a1360 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -2,6 +2,8 @@
 @import "tw-animate-css";
 @import "../vendor/shadcn-tailwind-4.13.0.css";
 
+.pwa-install{position:fixed;z-index:60;right:1rem;bottom:1rem;display:flex;align-items:center;gap:.75rem;max-width:min(28rem,calc(100vw - 2rem));padding:.8rem .9rem;color:#eff6ff;background:rgba(15,23,42,.94);border:1px solid rgba(147,197,253,.45);border-radius:.85rem;box-shadow:0 12px 30px rgba(15,23,42,.28);font-size:.875rem}.pwa-install button{flex:none;padding:.45rem .7rem;border-radius:.55rem;border:0;background:#60a5fa;color:#0f172a;font-weight:700;cursor:pointer}.pwa-ios{color:#bfdbfe;white-space:nowrap}@media(max-width:520px){.pwa-install{left:.75rem;right:.75rem;bottom:.75rem;flex-wrap:wrap}.pwa-ios{white-space:normal}}
+
 @utility scrollbar-thin {
   scrollbar-width: thin;
 }
diff --git a/app/layout.tsx b/app/layout.tsx
index 34ad7ea..72091f4 100644
--- a/app/layout.tsx
+++ b/app/layout.tsx
@@ -8,6 +8,7 @@ export const metadata: Metadata = {
   icons: {
     icon: "/favicon.svg",
     shortcut: "/favicon.svg",
+    apple: "/icon-192.png",
   },
   manifest: "/manifest.webmanifest",
   applicationName: "大学英语六级 · 90天打卡",
diff --git a/app/pwa-register.tsx b/app/pwa-register.tsx
index efda7f1..38bc645 100644
--- a/app/pwa-register.tsx
+++ b/app/pwa-register.tsx
@@ -1,3 +1,23 @@
 "use client";
-import { useEffect } from "react";
-export default function PwaRegister() { useEffect(() => { if ("serviceWorker" in navigator) navigator.serviceWorker.register("/sw.js").catch(() => undefined); }, []); return null; }
+import { useEffect, useState } from "react";
+
+type InstallPrompt = Event & { prompt: () => Promise<void>; userChoice: Promise<{ outcome: "accepted" | "dismissed" }> };
+
+export default function PwaRegister() {
+  const [prompt, setPrompt] = useState<InstallPrompt | null>(null);
+  const [isIos, setIsIos] = useState(false);
+
+  useEffect(() => {
+    if ("serviceWorker" in navigator) navigator.serviceWorker.register("/sw.js", { updateViaCache: "none" }).catch(() => undefined);
+    setIsIos(/iphone|ipad|ipod/i.test(navigator.userAgent));
+    const receivePrompt = (event: Event) => { event.preventDefault(); setPrompt(event as InstallPrompt); };
+    window.addEventListener("beforeinstallprompt", receivePrompt);
+    return () => window.removeEventListener("beforeinstallprompt", receivePrompt);
+  }, []);
+
+  if (!prompt && !isIos) return null;
+  return <div className="pwa-install" role="status">
+    <span>把打卡站点安装到桌面，打开更快捷。</span>
+    {prompt ? <button onClick={async () => { await prompt.prompt(); const result = await prompt.userChoice; if (result.outcome === "accepted") setPrompt(null); }}>安装应用</button> : <span className="pwa-ios">Safari 点“分享”→“添加到主屏幕”</span>}
+  </div>;
+}
diff --git a/public/icon-192.png b/public/icon-192.png
new file mode 100644
index 0000000..7273a8d
Binary files /dev/null and b/public/icon-192.png differ
diff --git a/public/icon-512.png b/public/icon-512.png
new file mode 100644
index 0000000..1dc1a9c
Binary files /dev/null and b/public/icon-512.png differ
diff --git a/public/manifest.webmanifest b/public/manifest.webmanifest
index aadb0e7..0fff5ca 100644
--- a/public/manifest.webmanifest
+++ b/public/manifest.webmanifest
@@ -8,5 +8,9 @@
   "display": "standalone",
   "background_color": "#eef4ff",
   "theme_color": "#1d4ed8",
-  "icons": [{ "src": "/favicon.svg", "sizes": "any", "type": "image/svg+xml", "purpose": "any maskable" }]
+  "icons": [
+    { "src": "/icon-192.png", "sizes": "192x192", "type": "image/png", "purpose": "any maskable" },
+    { "src": "/icon-512.png", "sizes": "512x512", "type": "image/png", "purpose": "any maskable" },
+    { "src": "/favicon.svg", "sizes": "any", "type": "image/svg+xml", "purpose": "any" }
+  ]
 }
diff --git a/public/sw.js b/public/sw.js
index 5da3fc5..6c1499f 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -1,10 +1,17 @@
-const CACHE = "cet6-shell-v1";
-const APP_SHELL = ["/", "/tasks", "/stats", "/review", "/manifest.webmanifest", "/favicon.svg"];
+const CACHE = "cet6-shell-v2";
+const APP_SHELL = ["/", "/manifest.webmanifest", "/favicon.svg", "/icon-192.png", "/icon-512.png"];
 self.addEventListener("install", event => event.waitUntil(caches.open(CACHE).then(cache => cache.addAll(APP_SHELL)).then(() => self.skipWaiting())));
-self.addEventListener("activate", event => event.waitUntil(self.clients.claim()));
+self.addEventListener("activate", event => event.waitUntil(
+  caches.keys().then(keys => Promise.all(keys.filter(key => key !== CACHE).map(key => caches.delete(key)))).then(() => self.clients.claim())
+));
 self.addEventListener("fetch", event => {
   const request = event.request;
   if (request.method !== "GET" || new URL(request.url).origin !== location.origin) return;
   if (request.url.includes("/api/")) return;
-  event.respondWith(fetch(request).then(response => { const copy = response.clone(); caches.open(CACHE).then(cache => cache.put(request, copy)); return response; }).catch(() => caches.match(request).then(found => found || caches.match("/"))));
+  event.respondWith(fetch(request).then(response => {
+    if (response.ok && new URL(request.url).pathname.startsWith("/_next/")) {
+      const copy = response.clone(); caches.open(CACHE).then(cache => cache.put(request, copy));
+    }
+    return response;
+  }).catch(() => caches.match(request).then(found => found || caches.match("/"))));
 });