src/App.tsx

@@ -10,6 +10,7 @@ import { I18nProvider } from "./i18n";
 import { MotionProvider } from "./motion";
 import { ToastProvider } from "./components/Toast";
 import { SaveToAlbumGuideProvider } from "./components/SaveToAlbumGuide";
+import { InAppDownloadGuideProvider } from "./components/InAppDownloadGuide";
 import { FavoritesProvider } from "./favorites/FavoritesProvider";
 import { AutoInjectedLogin } from "./wallet/AutoInjectedLogin";
 import { RainbowWalletProvider } from "./wallet/RainbowWalletProvider";
@@ -62,120 +63,127 @@ export default function App() {
               </RainbowWalletProvider>
             </WalletStackErrorBoundary>
             <FavoritesProvider>
-              <SaveToAlbumGuideProvider>
+              <InAppDownloadGuideProvider>
-                <AdminRouterModeProvider value="absolute">
+                <SaveToAlbumGuideProvider>
-                  <ImageLightboxProvider>
+                  <AdminRouterModeProvider value="absolute">
-                    <VideoPlayerProvider>
+                    <ImageLightboxProvider>
-                      <PageTitleProvider>
+                      <VideoPlayerProvider>
-                        <BrowserRouter>
+                        <PageTitleProvider>
-                          <ScrollToTop />
+                          <BrowserRouter>
-                          <Routes>
+                            <ScrollToTop />
-                            <Route element={<PublicLayout />}>
+                            <Routes>
-                              <Route
+                              <Route element={<PublicLayout />}>
-                                path="/"
+                                <Route
-                                element={<LocalizedHomePage targetLang="en" />}
+                                  path="/"
-                              />
+                                  element={
-                              <Route path="/browse" element={<Browse />} />
+                                    <LocalizedHomePage targetLang="en" />
-                              <Route
+                                  }
-                                path="/categories"
+                                />
-                                element={<CategoriesPage />}
+                                <Route path="/browse" element={<Browse />} />
-                              />
+                                <Route
-                              <Route
+                                  path="/categories"
-                                path="/official-recommendations"
+                                  element={<CategoriesPage />}
-                                element={<OfficialRecommendationsPage />}
+                                />
-                              />
+                                <Route
-                              <Route
+                                  path="/official-recommendations"
-                                path="/category/:slug"
+                                  element={<OfficialRecommendationsPage />}
-                                element={<CategoryPage />}
+                                />
-                              />
+                                <Route
-                              <Route path="/search" element={<SearchPage />} />
+                                  path="/category/:slug"
-                              <Route
+                                  element={<CategoryPage />}
-                                path="/resource/:id"
+                                />
-                                element={<PostRedirect />}
+                                <Route
-                              />
+                                  path="/search"
-                              <Route
+                                  element={<SearchPage />}
-                                path="/favorites"
+                                />
-                                element={<Favorites />}
+                                <Route
-                              />
+                                  path="/resource/:id"
+                                  element={<PostRedirect />}
+                                />
+                                <Route
+                                  path="/favorites"
+                                  element={<Favorites />}
+                                />
 
-                              {localizedHomeRoutes.map((route) => (
+                                {localizedHomeRoutes.map((route) => (
-                                <Route key={route.path} path={route.path}>
+                                  <Route key={route.path} path={route.path}>
+                                    <Route
+                                      index
+                                      element={
+                                        <LocalizedHomePage
+                                          targetLang={route.lang}
+                                        />
+                                      }
+                                    />
+                                    <Route path="browse" element={<Browse />} />
+                                    <Route
+                                      path="categories"
+                                      element={<CategoriesPage />}
+                                    />
+                                    <Route
+                                      path="official-recommendations"
+                                      element={<OfficialRecommendationsPage />}
+                                    />
+                                    <Route
+                                      path="category/:slug"
+                                      element={<CategoryPage />}
+                                    />
+                                    <Route
+                                      path="search"
+                                      element={<SearchPage />}
+                                    />
+                                    <Route
+                                      path="resource/:id"
+                                      element={<PostRedirect />}
+                                    />
+                                    <Route
+                                      path="favorites"
+                                      element={<Favorites />}
+                                    />
+                                  </Route>
+                                ))}
+                              </Route>
+
+                              {/* Legacy long-form language URLs → short-code
+                                redirects. Shared links (e.g. WeChat) keep working. */}
+                              {legacyLanguageRedirects.map((redirect) => (
+                                <Route key={redirect.from}>
                                   <Route
-                                    index
+                                    path={redirect.from}
                                     element={
-                                      <LocalizedHomePage
+                                      <LegacyLangRedirect to={redirect.to} />
-                                        targetLang={route.lang}
-                                      />
                                     }
                                   />
-                                  <Route path="browse" element={<Browse />} />
                                   <Route
-                                    path="categories"
+                                    path={`${redirect.from}/*`}
-                                    element={<CategoriesPage />}
+                                    element={
-                                  />
+                                      <LegacyLangRedirect to={redirect.to} />
-                                  <Route
+                                    }
-                                    path="official-recommendations"
-                                    element={<OfficialRecommendationsPage />}
-                                  />
-                                  <Route
-                                    path="category/:slug"
-                                    element={<CategoryPage />}
-                                  />
-                                  <Route
-                                    path="search"
-                                    element={<SearchPage />}
-                                  />
-                                  <Route
-                                    path="resource/:id"
-                                    element={<PostRedirect />}
-                                  />
-                                  <Route
-                                    path="favorites"
-                                    element={<Favorites />}
                                   />
                                 </Route>
                               ))}
-                            </Route>
 
-                            {/* Legacy long-form language URLs → short-code
+                              {adminEnabled ? (
-                                redirects. Shared links (e.g. WeChat) keep working. */}
+                                AdminRouteTree()
-                            {legacyLanguageRedirects.map((redirect) => (
+                              ) : (
-                              <Route key={redirect.from}>
                                 <Route
-                                  path={redirect.from}
+                                  path={`${adminUiPrefix}/*`}
-                                  element={
+                                  element={<Navigate to="/" replace />}
-                                    <LegacyLangRedirect to={redirect.to} />
-                                  }
                                 />
-                                <Route
+                              )}
-                                  path={`${redirect.from}/*`}
-                                  element={
-                                    <LegacyLangRedirect to={redirect.to} />
-                                  }
-                                />
-                              </Route>
-                            ))}
 
-                            {adminEnabled ? (
-                              AdminRouteTree()
-                            ) : (
                               <Route
-                                path={`${adminUiPrefix}/*`}
+                                path="*"
                                 element={<Navigate to="/" replace />}
                               />
-                            )}
+                            </Routes>
-
+                          </BrowserRouter>
-                            <Route
+                        </PageTitleProvider>
-                              path="*"
+                      </VideoPlayerProvider>
-                              element={<Navigate to="/" replace />}
+                    </ImageLightboxProvider>
-                            />
+                  </AdminRouterModeProvider>
-                          </Routes>
+                </SaveToAlbumGuideProvider>
-                        </BrowserRouter>
+              </InAppDownloadGuideProvider>
-                      </PageTitleProvider>
-                    </VideoPlayerProvider>
-                  </ImageLightboxProvider>
-                </AdminRouterModeProvider>
-              </SaveToAlbumGuideProvider>
             </FavoritesProvider>
           </WalletProvider>
         </ToastProvider>

src/components/InAppDownloadGuide.tsx

@@ -0,0 +1,179 @@
+import { Copy, X } from "lucide-react";
+import { useEffect, useState, type ReactNode } from "react";
+import { createPortal } from "react-dom";
+import { useI18n } from "../i18n";
+import { useToast } from "./Toast";
+import {
+  IN_APP_DOWNLOAD_GUIDE_EVENT,
+  type InAppDownloadGuideDetail,
+} from "./messageStream/utils/downloadFile";
+import { inAppBrowserName } from "../utils/inAppBrowser";
+
+async function copyTextToClipboard(text: string): Promise<boolean> {
+  try {
+    if (
+      typeof navigator !== "undefined" &&
+      navigator.clipboard &&
+      typeof navigator.clipboard.writeText === "function"
+    ) {
+      await navigator.clipboard.writeText(text);
+      return true;
+    }
+  } catch {
+    // fall through to legacy path
+  }
+  try {
+    const ta = document.createElement("textarea");
+    ta.value = text;
+    ta.setAttribute("readonly", "");
+    ta.style.position = "fixed";
+    ta.style.top = "0";
+    ta.style.left = "0";
+    ta.style.opacity = "0";
+    document.body.append(ta);
+    ta.select();
+    const ok = document.execCommand("copy");
+    ta.remove();
+    return ok;
+  } catch {
+    return false;
+  }
+}
+
+export function InAppDownloadGuideProvider({
+  children,
+}: {
+  children: ReactNode;
+}) {
+  const { t } = useI18n();
+  const { showToast } = useToast();
+  const [detail, setDetail] = useState<InAppDownloadGuideDetail | null>(null);
+
+  useEffect(() => {
+    const onShow = (event: Event) => {
+      const ce = event as CustomEvent<InAppDownloadGuideDetail>;
+      if (!ce.detail) return;
+      setDetail(ce.detail);
+    };
+    window.addEventListener(IN_APP_DOWNLOAD_GUIDE_EVENT, onShow);
+    return () =>
+      window.removeEventListener(IN_APP_DOWNLOAD_GUIDE_EVENT, onShow);
+  }, []);
+
+  useEffect(() => {
+    if (!detail) return;
+    const onKey = (event: KeyboardEvent) => {
+      if (event.key === "Escape") setDetail(null);
+    };
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+  }, [detail]);
+
+  const close = () => setDetail(null);
+
+  const handleCopy = async () => {
+    if (!detail) return;
+    const ok = await copyTextToClipboard(detail.url);
+    if (ok) {
+      showToast(t("inAppDownloadCopied"));
+    } else {
+      showToast(t("inAppDownloadCopyFail"), "error");
+    }
+  };
+
+  const browser = inAppBrowserName();
+  const intro = browser
+    ? t("inAppDownloadIntroNamed").replace("{browser}", browser)
+    : t("inAppDownloadIntro");
+
+  return (
+    <>
+      {children}
+      {detail
+        ? createPortal(
+            <div
+              role="dialog"
+              aria-modal="true"
+              aria-labelledby="in-app-download-guide-title"
+              className="fixed inset-0 z-[140] flex items-center justify-center bg-black/70 px-4 backdrop-blur-sm"
+              onClick={close}
+            >
+              <div
+                className="w-full max-w-md overflow-hidden rounded-3xl border border-white/10 bg-[#1c1c21] text-neutral-100 shadow-2xl shadow-black/70"
+                onClick={(event) => event.stopPropagation()}
+              >
+                <div className="flex items-start justify-between gap-4 border-b border-white/10 px-5 py-4">
+                  <div className="min-w-0">
+                    <p className="text-xs font-semibold uppercase tracking-[0.2em] text-ark-gold/80">
+                      {t("download")}
+                    </p>
+                    <h2
+                      id="in-app-download-guide-title"
+                      className="mt-1 text-lg font-semibold text-white"
+                    >
+                      {t("inAppDownloadTitle")}
+                    </h2>
+                  </div>
+                  <button
+                    type="button"
+                    onClick={close}
+                    className="flex h-9 w-9 shrink-0 items-center justify-center rounded-full bg-white/10 text-white transition hover:bg-white/20 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ark-gold/80"
+                    aria-label={t("cancel")}
+                  >
+                    <X className="h-5 w-5" />
+                  </button>
+                </div>
+
+                <div className="space-y-4 px-5 py-5">
+                  <p className="text-sm leading-6 text-neutral-300">{intro}</p>
+
+                  <ol className="space-y-3 text-sm leading-6 text-neutral-100">
+                    <li className="flex gap-3">
+                      <span className="flex h-7 w-7 shrink-0 items-center justify-center rounded-full bg-ark-gold text-sm font-bold text-black">
+                        1
+                      </span>
+                      <span className="pt-0.5">
+                        {t("inAppDownloadStepCopy")}
+                      </span>
+                    </li>
+                    <li className="flex gap-3">
+                      <span className="flex h-7 w-7 shrink-0 items-center justify-center rounded-full bg-ark-gold text-sm font-bold text-black">
+                        2
+                      </span>
+                      <span className="pt-0.5">
+                        {t("inAppDownloadStepOpen")}
+                      </span>
+                    </li>
+                    <li className="flex gap-3">
+                      <span className="flex h-7 w-7 shrink-0 items-center justify-center rounded-full bg-ark-gold text-sm font-bold text-black">
+                        3
+                      </span>
+                      <span className="pt-0.5">
+                        {t("inAppDownloadStepDownload")}
+                      </span>
+                    </li>
+                  </ol>
+
+                  <div className="rounded-2xl border border-white/10 bg-black/30 p-3">
+                    <p className="break-all text-xs leading-5 text-neutral-300">
+                      {detail.url}
+                    </p>
+                  </div>
+
+                  <button
+                    type="button"
+                    onClick={handleCopy}
+                    className="flex h-11 w-full items-center justify-center gap-2 rounded-full bg-ark-gold px-4 text-sm font-semibold text-black transition hover:bg-ark-gold2 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ark-gold/80 focus-visible:ring-offset-2 focus-visible:ring-offset-[#1c1c21]"
+                  >
+                    <Copy className="h-4 w-4" />
+                    {t("copyLink")}
+                  </button>
+                </div>
+              </div>
+            </div>,
+            document.body,
+          )
+        : null}
+    </>
+  );
+}

src/components/LatestUpdateCard.tsx

@@ -38,7 +38,9 @@ function LatestActions({
     if (!attachment || isDownloading) return;
     setIsDownloading(true);
     try {
-      await downloadAttachment(post.id, attachment.id, attachment.filename);
+      await downloadAttachment(post.id, attachment.id, attachment.filename, {
+        sizeBytes: attachment.sizeBytes,
+      });
       const mediaKind = mediaSaveKindFromAttachment(attachment);
       if (mediaKind) showSaveToAlbumGuide(mediaKind);
     } catch {

src/components/messageStream/AttachmentDownloadPill.tsx

@@ -53,7 +53,9 @@ export function AttachmentDownloadPill({
     pauseActiveVideos();
     setIsDownloading(true);
     try {
-      await downloadAttachment(postId, attachment.id, attachment.filename);
+      await downloadAttachment(postId, attachment.id, attachment.filename, {
+        sizeBytes: attachment.sizeBytes,
+      });
       const mediaKind = mediaSaveKindFromAttachment(attachment);
       if (mediaKind) showSaveToAlbumGuide(mediaKind);
     } catch {

src/components/messageStream/BubbleAttachmentDownloadButton.tsx

@@ -32,7 +32,9 @@ export function BubbleAttachmentDownloadButton({
     pauseActiveVideos();
     setIsDownloading(true);
     try {
-      await downloadAttachment(postId, attachment.id, displayFilename);
+      await downloadAttachment(postId, attachment.id, displayFilename, {
+        sizeBytes: attachment.sizeBytes,
+      });
       const mediaKind = mediaSaveKindFromAttachment(attachment);
       if (mediaKind) showSaveToAlbumGuide(mediaKind);
     } catch {

src/components/messageStream/bubbles/FileDocBubble.tsx

@@ -102,7 +102,9 @@ function LatestFileCard({ post }: { post: Post }) {
     if (isDownloading) return;
     setIsDownloading(true);
     try {
-      await downloadAttachment(post.id, att.id, displayFilename);
+      await downloadAttachment(post.id, att.id, displayFilename, {
+        sizeBytes: att.sizeBytes,
+      });
       const mediaKind = mediaSaveKindFromAttachment(att);
       if (mediaKind) showSaveToAlbumGuide(mediaKind);
     } catch {

src/components/messageStream/bubbles/VideoBubble.tsx

@@ -183,7 +183,9 @@ function AttachmentListDownloadButton({
     pauseActiveVideos();
     setIsDownloading(true);
     try {
-      await downloadAttachment(postId, attachment.id, attachment.filename);
+      await downloadAttachment(postId, attachment.id, attachment.filename, {
+        sizeBytes: attachment.sizeBytes,
+      });
       showSaveToAlbumGuide("video");
     } catch {
       showToast(t("downloadFail"), "error");

src/components/messageStream/utils/downloadFile.ts

@@ -1,4 +1,18 @@
 import { assetUrl } from "../../../api";
+import { isInAppBrowser } from "../../../utils/inAppBrowser";
+
+export const IN_APP_DOWNLOAD_GUIDE_EVENT = "ark:in-app-download-guide";
+
+export type InAppDownloadGuideDetail = { url: string; filename: string };
+
+/**
+ * Files larger than this skip the fetch→Blob path so mobile WebViews and
+ * memory-constrained devices do not OOM. They fall back to the anchor
+ * download (relies on the backend's `Content-Disposition: attachment`).
+ */
+const MAX_BLOB_DOWNLOAD_BYTES = 50 * 1024 * 1024;
+
+export type DownloadOptions = { sizeBytes?: number };
 
 export function pauseActiveVideos() {
   document.querySelectorAll("video").forEach((video) => {
@@ -18,12 +32,62 @@ export async function downloadAttachment(
   postId: string,
   attachmentId: string,
   filename: string,
+  options?: DownloadOptions,
 ) {
-  return downloadFile(attachmentDownloadUrl(postId, attachmentId), filename);
+  return downloadFile(
+    attachmentDownloadUrl(postId, attachmentId),
+    filename,
+    options,
+  );
 }
 
-export async function downloadFile(url: string, filename: string) {
+export async function downloadFile(
-  triggerDownload(url, filename || "download");
+  url: string,
+  filename: string,
+  options?: DownloadOptions,
+) {
+  const safeFilename = filename || "download";
+
+  // In-app WebViews (WeChat / TokenPocket / Telegram / iOS WKWebView / …)
+  // ignore `Content-Disposition: attachment` and have no system download
+  // manager, so an anchor click would just open the file inline. Surface an
+  // "open in external browser" guide instead of silently failing the user.
+  if (typeof window !== "undefined" && isInAppBrowser()) {
+    window.dispatchEvent(
+      new CustomEvent<InAppDownloadGuideDetail>(IN_APP_DOWNLOAD_GUIDE_EVENT, {
+        detail: { url, filename: safeFilename },
+      }),
+    );
+    return;
+  }
+
+  // Normal browsers: prefer fetch → Blob → object URL so the file always lands
+  // in the Downloads folder with the original filename, even when the browser
+  // would otherwise inline-preview the response (Chrome and Safari do this for
+  // PDFs / images regardless of Content-Disposition). Fall back to the anchor
+  // download for large files (avoid loading them entirely into memory) or when
+  // fetch fails for any reason.
+  const sizeBytes = options?.sizeBytes ?? 0;
+  if (sizeBytes <= MAX_BLOB_DOWNLOAD_BYTES) {
+    try {
+      const res = await fetch(url, { credentials: "omit" });
+      if (res.ok) {
+        const blob = await res.blob();
+        const objectUrl = URL.createObjectURL(blob);
+        try {
+          triggerDownload(objectUrl, safeFilename);
+        } finally {
+          // Give the browser a moment to start the download before revoking.
+          window.setTimeout(() => URL.revokeObjectURL(objectUrl), 4000);
+        }
+        return;
+      }
+    } catch {
+      // fall through to anchor fallback
+    }
+  }
+
+  triggerDownload(url, safeFilename);
 }
 
 function triggerDownload(url: string, filename: string) {

src/locales/en.ts

@@ -264,4 +264,16 @@ export const enDict: Dict = {
   featureUnavailableDesc: "This feature is not available yet.",
   confirm: "Got it",
   backToHome: "Back to Home",
+  inAppDownloadTitle: "Please open in your system browser to download",
+  inAppDownloadIntro:
+    "Your current in-app browser cannot download files. Open the page in your system browser (Safari, Chrome, etc.) and tap download again.",
+  inAppDownloadIntroNamed:
+    "{browser} cannot download files directly. Open the page in your system browser (Safari, Chrome, etc.) and tap download again.",
+  inAppDownloadStepCopy: "Tap “Copy link” below.",
+  inAppDownloadStepOpen:
+    "Open the menu (top-right), choose “Open in browser”, and paste the link if needed.",
+  inAppDownloadStepDownload:
+    "Tap the download button on the page — the file will save to your downloads.",
+  inAppDownloadCopied: "Link copied",
+  inAppDownloadCopyFail: "Could not copy the link, please copy it manually",
 };

src/locales/id.ts

@@ -267,4 +267,16 @@ export const idDict: Dict = {
   featureUnavailableDesc: "Fitur ini belum tersedia.",
   confirm: "Mengerti",
   backToHome: "Kembali ke Beranda",
+  inAppDownloadTitle: "Silakan buka di peramban sistem untuk mengunduh",
+  inAppDownloadIntro:
+    "Peramban dalam aplikasi saat ini tidak dapat mengunduh berkas. Buka halaman ini di peramban sistem (Safari, Chrome, dll.) lalu ketuk unduh lagi.",
+  inAppDownloadIntroNamed:
+    "{browser} tidak dapat mengunduh berkas secara langsung. Buka halaman ini di peramban sistem (Safari, Chrome, dll.) lalu ketuk unduh lagi.",
+  inAppDownloadStepCopy: "Ketuk “Salin tautan” di bawah.",
+  inAppDownloadStepOpen:
+    "Buka menu di kanan atas, pilih “Buka di peramban”, tempelkan tautan jika diperlukan.",
+  inAppDownloadStepDownload:
+    "Di peramban sistem, ketuk lagi tombol unduh dan berkas akan tersimpan.",
+  inAppDownloadCopied: "Tautan disalin",
+  inAppDownloadCopyFail: "Tidak dapat menyalin, silakan salin secara manual",
 };

src/locales/ja.ts

@@ -268,4 +268,16 @@ export const jaDict: Dict = {
   featureUnavailableDesc: "この機能はまだご利用いただけません。",
   confirm: "了解",
   backToHome: "ホームへ戻る",
+  inAppDownloadTitle: "システムブラウザで開いてダウンロードしてください",
+  inAppDownloadIntro:
+    "現在のアプリ内ブラウザはファイルをダウンロードできません。Safari や Chrome などのシステムブラウザでページを開いてから、もう一度ダウンロードしてください。",
+  inAppDownloadIntroNamed:
+    "{browser} のアプリ内ブラウザはファイルを直接ダウンロードできません。Safari や Chrome などのシステムブラウザでページを開いてから、もう一度ダウンロードしてください。",
+  inAppDownloadStepCopy: "下の「リンクをコピー」をタップします。",
+  inAppDownloadStepOpen:
+    "右上のメニューから「ブラウザで開く」を選び、必要に応じてリンクを貼り付けます。",
+  inAppDownloadStepDownload:
+    "システムブラウザで再度ダウンロードボタンをタップすると、ファイルがダウンロード先に保存されます。",
+  inAppDownloadCopied: "リンクをコピーしました",
+  inAppDownloadCopyFail: "コピーに失敗しました。手動でコピーしてください",
 };

src/locales/ko.ts

@@ -263,4 +263,16 @@ export const koDict: Dict = {
   featureUnavailableDesc: "이 기능은 아직 사용할 수 없습니다.",
   confirm: "확인",
   backToHome: "홈으로",
+  inAppDownloadTitle: "시스템 브라우저에서 열어 다운로드하세요",
+  inAppDownloadIntro:
+    "현재 앱 내 브라우저는 파일을 다운로드할 수 없습니다. Safari나 Chrome 등 시스템 브라우저에서 페이지를 연 다음 다시 다운로드해 주세요.",
+  inAppDownloadIntroNamed:
+    "{browser} 앱 내 브라우저는 파일을 직접 다운로드할 수 없습니다. Safari나 Chrome 등 시스템 브라우저에서 페이지를 연 다음 다시 다운로드해 주세요.",
+  inAppDownloadStepCopy: "아래의 “링크 복사”를 누릅니다.",
+  inAppDownloadStepOpen:
+    "오른쪽 위 메뉴에서 “브라우저로 열기”를 선택하고 필요하면 링크를 붙여 넣습니다.",
+  inAppDownloadStepDownload:
+    "시스템 브라우저에서 다운로드 버튼을 다시 누르면 파일이 저장됩니다.",
+  inAppDownloadCopied: "링크를 복사했습니다",
+  inAppDownloadCopyFail: "복사하지 못했습니다. 직접 복사해 주세요",
 };

src/locales/ms.ts

@@ -266,4 +266,16 @@ export const msDict: Dict = {
   featureUnavailableDesc: "Ciri ini belum tersedia.",
   confirm: "Faham",
   backToHome: "Kembali ke Laman Utama",
+  inAppDownloadTitle: "Sila buka dalam pelayar sistem untuk muat turun",
+  inAppDownloadIntro:
+    "Pelayar dalam aplikasi semasa tidak dapat memuat turun fail. Buka halaman ini dalam pelayar sistem (Safari, Chrome, dsb.), kemudian ketik muat turun semula.",
+  inAppDownloadIntroNamed:
+    "{browser} tidak dapat memuat turun fail secara langsung. Buka halaman ini dalam pelayar sistem (Safari, Chrome, dsb.), kemudian ketik muat turun semula.",
+  inAppDownloadStepCopy: "Ketik “Salin pautan” di bawah.",
+  inAppDownloadStepOpen:
+    "Buka menu di atas kanan, pilih “Buka dalam pelayar”, tampal pautan jika perlu.",
+  inAppDownloadStepDownload:
+    "Dalam pelayar sistem, ketik butang muat turun semula dan fail akan disimpan.",
+  inAppDownloadCopied: "Pautan disalin",
+  inAppDownloadCopyFail: "Tidak dapat menyalin, sila salin secara manual",
 };

src/locales/vi.ts

@@ -262,4 +262,16 @@ export const viDict: Dict = {
   featureUnavailableDesc: "Tính năng này hiện chưa khả dụng.",
   confirm: "Đã hiểu",
   backToHome: "Về trang chủ",
+  inAppDownloadTitle: "Vui lòng mở bằng trình duyệt hệ thống để tải",
+  inAppDownloadIntro:
+    "Trình duyệt trong ứng dụng hiện tại không thể tải tệp. Hãy mở trang trong trình duyệt hệ thống (Safari, Chrome…) rồi nhấn tải lại.",
+  inAppDownloadIntroNamed:
+    "{browser} không thể tải tệp trực tiếp. Hãy mở trang trong trình duyệt hệ thống (Safari, Chrome…) rồi nhấn tải lại.",
+  inAppDownloadStepCopy: "Nhấn “Sao chép liên kết” bên dưới.",
+  inAppDownloadStepOpen:
+    "Mở menu ở góc trên bên phải, chọn “Mở bằng trình duyệt”, dán liên kết nếu cần.",
+  inAppDownloadStepDownload:
+    "Trong trình duyệt hệ thống, nhấn lại nút tải để lưu tệp.",
+  inAppDownloadCopied: "Đã sao chép liên kết",
+  inAppDownloadCopyFail: "Không sao chép được, vui lòng tự sao chép",
 };

src/locales/zh-CN.ts

@@ -245,4 +245,16 @@ export const zhDict: Dict = {
   featureUnavailableDesc: "该功能暂未开放。",
   confirm: "知道了",
   backToHome: "返回首页",
+  inAppDownloadTitle: "请使用系统浏览器打开后下载",
+  inAppDownloadIntro:
+    "当前内置浏览器无法直接下载文件，请在系统浏览器（Safari、Chrome 等）中打开页面后再点击下载。",
+  inAppDownloadIntroNamed:
+    "{browser} 内置浏览器无法直接下载文件，请在系统浏览器（Safari、Chrome 等）中打开页面后再点击下载。",
+  inAppDownloadStepCopy: "点击下方「复制链接」。",
+  inAppDownloadStepOpen:
+    "点右上角菜单，选择「在浏览器中打开」，如需要请把刚才复制的链接粘贴进地址栏。",
+  inAppDownloadStepDownload:
+    "在系统浏览器中再次点击下载按钮，文件会保存到下载文件夹。",
+  inAppDownloadCopied: "链接已复制",
+  inAppDownloadCopyFail: "复制失败，请手动复制",
 };

src/utils/inAppBrowser.ts

@@ -0,0 +1,43 @@
+/**
+ * Detect popular in-app WebViews that block file downloads or ignore
+ * `Content-Disposition: attachment`, so the UI can show an "open in external
+ * browser" guide instead of silently opening the file inline.
+ */
+
+function ua(): string {
+  if (typeof navigator === "undefined") return "";
+  return navigator.userAgent || "";
+}
+
+const PATTERNS: Array<{ re: RegExp; name: string }> = [
+  { re: /MicroMessenger/i, name: "WeChat" },
+  { re: /TokenPocket/i, name: "TokenPocket" },
+  { re: /imToken/i, name: "imToken" },
+  { re: /Trust(Wallet|Browser)/i, name: "Trust Wallet" },
+  { re: /MetaMask/i, name: "MetaMask" },
+  { re: /Telegram/i, name: "Telegram" },
+  { re: /\bLine\//i, name: "LINE" },
+  { re: /FBAN|FBAV/i, name: "Facebook" },
+  { re: /Instagram/i, name: "Instagram" },
+  { re: /Twitter|\bX\//i, name: "Twitter/X" },
+  { re: /Weibo/i, name: "Weibo" },
+  { re: /MQQBrowser/i, name: "QQ Browser" },
+  { re: /\bQQ\//i, name: "QQ" },
+  { re: /MiuiBrowser/i, name: "Mi Browser" },
+  { re: /Snapchat/i, name: "Snapchat" },
+];
+
+export function isInAppBrowser(): boolean {
+  const agent = ua();
+  if (!agent) return false;
+  return PATTERNS.some(({ re }) => re.test(agent));
+}
+
+export function inAppBrowserName(): string | null {
+  const agent = ua();
+  if (!agent) return null;
+  for (const { re, name } of PATTERNS) {
+    if (re.test(agent)) return name;
+  }
+  return null;
+}