diff --git a/backend/app/main.py b/backend/app/main.py
index b03b7c3..de1e10f 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -227,10 +227,16 @@ async def unhandled_error_handler(_request: Request, exc: Exception):
 # pm, users) keep them — the global dependency guarantees nothing is open
 # by omission.
 from app.routers.auth import router as _auth_router  # noqa: E402
+# The files router enforces its own access check per route: a browser cannot
+# attach an Authorization header to <iframe>/<img> loads, so the two file GET
+# routes accept a short-lived signed ?t= token as well as a Bearer session.
+from app.routers.files import router as _files_router  # noqa: E402
 
 for router in ROUTERS:
     if router is _auth_router:
         app.include_router(router, prefix=API_V1_PREFIX)
+    elif router is _files_router:
+        app.include_router(router, prefix=API_V1_PREFIX)
     else:
         app.include_router(router, prefix=API_V1_PREFIX, dependencies=[Depends(get_current_user)])
 
diff --git a/backend/app/routers/files.py b/backend/app/routers/files.py
index df1d06c..791dd16 100644
--- a/backend/app/routers/files.py
+++ b/backend/app/routers/files.py
@@ -17,14 +17,15 @@ import os
 import uuid
 from urllib.parse import quote
 
-from fastapi import APIRouter, Depends, File, Response, UploadFile
+from fastapi import APIRouter, Depends, File, Request, Response, UploadFile
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.auth import require_role
+from app.auth import UserContext, get_current_user, get_optional_user, require_role
 from app.db.engine import get_db
 from app.models.procurement import Quote
 from app.services import file_service
-from app.utils.errors import NotFoundError, ValidationError
+from app.utils.errors import NotFoundError, UnauthorizedError, ValidationError
+from app.utils.preview_token import make_preview_token, verify_preview_token
 
 router = APIRouter(prefix="/quotes", tags=["files"])
 
@@ -41,13 +42,17 @@ ALLOWED_EXTENSIONS = {".png", ".jpg", ".jpeg", ".webp", ".gif", ".pdf"}
 MAX_FILE_SIZE_BYTES = 5 * 1024 * 1024
 
 
-def _content_disposition(file_name: str) -> str:
+def _content_disposition(file_name: str, inline: bool = False) -> str:
     """Header-safe Content-Disposition for non-ASCII (e.g. Persian) filenames.
 
     HTTP headers are encoded as latin-1, so a Persian name raises
     UnicodeEncodeError and kills the response. Per RFC 6266 / RFC 5987 the
     UTF-8 name goes percent-encoded in ``filename*``, with an ASCII fallback
     in ``filename`` for old clients.
+
+    ``inline=True`` makes the browser render the file (PDF in a viewer,
+    image in the tab) instead of downloading it — required by the preview
+    modal, whose <iframe> would otherwise trigger a download.
     """
     raw = file_name.encode("ascii", "ignore").decode("ascii")
     # keep the fallback header-safe: no quotes, no control characters
@@ -56,9 +61,37 @@ def _content_disposition(file_name: str) -> str:
     stem = fallback[: -len(ext)].strip() if ext and fallback.lower().endswith(ext.lower()) else fallback
     if not stem or not any(ch.isalnum() for ch in stem):
         # nothing meaningful survived ASCII-folding (e.g. a pure-Persian
-        # name): use a generic attachment name that keeps the extension
-        fallback = f"attachment{ext}" if ext else "attachment"
-    return f"attachment; filename=\"{fallback}\"; filename*=UTF-8''{quote(file_name)}"
+        # name): use a generic name that keeps the extension
+        fallback = f"{'preview' if inline else 'attachment'}{ext}" if ext else (
+            "preview" if inline else "attachment"
+        )
+    kind = "inline" if inline else "attachment"
+    return f"{kind}; filename=\"{fallback}\"; filename*=UTF-8''{quote(file_name)}"
+
+
+async def _require_file_access(
+    request: Request,
+    token: str | None,
+    quote_id: uuid.UUID,
+    kind: str,
+    attachment_id: uuid.UUID,
+    db: AsyncSession,
+) -> None:
+    """Authorise a file read by session header OR a signed ``?t=`` token.
+
+    These two GET routes sit outside the global Bearer dependency because a
+    browser cannot attach an Authorization header to <iframe>/<img> loads.
+    A caller is accepted when it presents either a valid Casdoor session
+    (resolved by get_optional_user) or a signed token scoped to exactly
+    this file, which expires within minutes.
+    """
+    if request is not None and request.headers.get("authorization"):
+        user = await get_optional_user(request, db)
+        if user is not None and user.role is not None:
+            return
+    if token and verify_preview_token(token, quote_id, kind, attachment_id):
+        return
+    raise UnauthorizedError("دسترسی به این فایل مجاز نیست — ابتدا وارد شوید")
 
 
 async def _quote_or_404(db: AsyncSession, quote_id: uuid.UUID) -> Quote:
@@ -92,7 +125,7 @@ async def _attachment_or_404(
 # Invoice — قابل بارگذاری در هر وضعیتی (از صفحه‌ی ویرایش)
 # ---------------------------------------------------------------------------
 
-@router.post("/{quote_id}/invoice", status_code=201)
+@router.post("/{quote_id}/invoice", status_code=201, dependencies=[Depends(get_current_user)])
 async def upload_invoice(quote_id: uuid.UUID, file: UploadFile = File(...), db: AsyncSession = Depends(get_db)):
     await _quote_or_404(db, quote_id)
     mime = _validate_upload(file)
@@ -103,29 +136,67 @@ async def upload_invoice(quote_id: uuid.UUID, file: UploadFile = File(...), db:
     return {"data": stored.to_dict()}
 
 
-@router.get("/{quote_id}/invoice")
+@router.get("/{quote_id}/invoice", dependencies=[Depends(get_current_user)])
 async def list_invoices(quote_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
     await _quote_or_404(db, quote_id)
     attachments = await file_service.list_for(db, quote_id, "invoice")
     return {"data": [a.to_dict() for a in attachments]}
 
 
+# ---------------------------------------------------------------------------
+# Preview URL — a real, short-lived URL the browser can load in an
+# <iframe>/<img> (which cannot send an Authorization header). Using a real
+# URL instead of a blob: avoids download managers that hijack blob URLs and
+# leave 0-byte files behind.
+# ---------------------------------------------------------------------------
+@router.get("/{quote_id}/preview-url/{kind}/{attachment_id}")
+async def preview_url(
+    quote_id: uuid.UUID,
+    kind: str,
+    attachment_id: uuid.UUID,
+    db: AsyncSession = Depends(get_db),
+    _ctx: UserContext = Depends(get_current_user),
+):
+    if kind not in ("invoice", "proforma"):
+        raise ValidationError("نوع پیوست نامعتبر است", field="kind")
+    await _quote_or_404(db, quote_id)
+    await _attachment_or_404(db, quote_id, attachment_id, kind)
+    token = make_preview_token(quote_id, kind, attachment_id)
+    # مسیر نسبی برگردانده می‌شود؛ فرانت با BASE_URL خودش کاملش می‌کند
+    return {
+        "data": {
+            "url": f"/quotes/{quote_id}/{kind}/{attachment_id}?disposition=inline&t={token}",
+            "token": token,
+        }
+    }
+
+
 @router.get("/{quote_id}/invoice/{attachment_id}")
-async def download_invoice(quote_id: uuid.UUID, attachment_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
+async def download_invoice(
+    quote_id: uuid.UUID,
+    attachment_id: uuid.UUID,
+    disposition: str = "attachment",
+    t: str | None = None,
+    request: Request = None,
+    db: AsyncSession = Depends(get_db),
+):
     await _quote_or_404(db, quote_id)
     attachment = await _attachment_or_404(db, quote_id, attachment_id, "invoice")
+    await _require_file_access(request, t, quote_id, "invoice", attachment_id, db)
     content = await file_service.read_bytes(attachment)
     return Response(
         content=content,
         media_type=attachment.mime_type,
         headers={
-            "Content-Disposition": _content_disposition(attachment.file_name),
+            "Content-Disposition": _content_disposition(
+                attachment.file_name, inline=disposition == "inline"
+            ),
             "X-File-Id": str(attachment.id),
         },
     )
 
 
-@router.delete("/{quote_id}/invoice/{attachment_id}", dependencies=[Depends(_attachment_deleter)])
+@router.delete("/{quote_id}/invoice/{attachment_id}", dependencies=[Depends(_attachment_deleter), Depends(get_current_user)])
 async def delete_invoice(quote_id: uuid.UUID, attachment_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
     await _quote_or_404(db, quote_id)
     attachment = await _attachment_or_404(db, quote_id, attachment_id, "invoice")
@@ -137,7 +208,7 @@ async def delete_invoice(quote_id: uuid.UUID, attachment_id: uuid.UUID, db: Asyn
 # Proforma — no status restriction
 # ---------------------------------------------------------------------------
 
-@router.post("/{quote_id}/proforma", status_code=201)
+@router.post("/{quote_id}/proforma", status_code=201, dependencies=[Depends(get_current_user)])
 async def upload_proforma(quote_id: uuid.UUID, file: UploadFile = File(...), db: AsyncSession = Depends(get_db)):
     await _quote_or_404(db, quote_id)
     mime = _validate_upload(file)
@@ -148,7 +219,7 @@ async def upload_proforma(quote_id: uuid.UUID, file: UploadFile = File(...), db:
     return {"data": stored.to_dict()}
 
 
-@router.get("/{quote_id}/proforma")
+@router.get("/{quote_id}/proforma", dependencies=[Depends(get_current_user)])
 async def list_proformas(quote_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
     await _quote_or_404(db, quote_id)
     attachments = await file_service.list_for(db, quote_id, "proforma")
@@ -156,21 +227,31 @@ async def list_proformas(quote_id: uuid.UUID, db: AsyncSession = Depends(get_db)
 
 
 @router.get("/{quote_id}/proforma/{attachment_id}")
-async def download_proforma(quote_id: uuid.UUID, attachment_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
+async def download_proforma(
+    quote_id: uuid.UUID,
+    attachment_id: uuid.UUID,
+    disposition: str = "attachment",
+    t: str | None = None,
+    request: Request = None,
+    db: AsyncSession = Depends(get_db),
+):
     await _quote_or_404(db, quote_id)
     attachment = await _attachment_or_404(db, quote_id, attachment_id, "proforma")
+    await _require_file_access(request, t, quote_id, "proforma", attachment_id, db)
     content = await file_service.read_bytes(attachment)
     return Response(
         content=content,
         media_type=attachment.mime_type,
         headers={
-            "Content-Disposition": _content_disposition(attachment.file_name),
+            "Content-Disposition": _content_disposition(
+                attachment.file_name, inline=disposition == "inline"
+            ),
             "X-File-Id": str(attachment.id),
         },
     )
 
 
-@router.delete("/{quote_id}/proforma/{attachment_id}", dependencies=[Depends(_attachment_deleter)])
+@router.delete("/{quote_id}/proforma/{attachment_id}", dependencies=[Depends(_attachment_deleter), Depends(get_current_user)])
 async def delete_proforma(quote_id: uuid.UUID, attachment_id: uuid.UUID, db: AsyncSession = Depends(get_db)):
     await _quote_or_404(db, quote_id)
     attachment = await _attachment_or_404(db, quote_id, attachment_id, "proforma")
diff --git a/backend/app/utils/preview_token.py b/backend/app/utils/preview_token.py
new file mode 100644
index 0000000..77b638c
--- /dev/null
+++ b/backend/app/utils/preview_token.py
@@ -0,0 +1,71 @@
+"""Ephemeral, URL-safe file-preview tokens.
+
+Why this exists
+---------------
+File downloads require an ``Authorization: Bearer`` header, but a browser
+cannot attach headers to the requests made by ``<iframe src>`` / ``<img
+src>`` — which is what the preview modal uses. The previous workaround
+fetched the bytes with ``fetch`` and rendered a local ``blob:`` URL, but
+download managers (IDM et al.) hook ``blob:`` URLs, fail to resolve them
+outside the originating document, and hand the browser a 0-byte file under
+a bare UUID name — so the preview broke and a junk download appeared.
+
+Instead we mint a short-lived HMAC token scoped to a single attachment and
+put it in the query string, giving the iframe a *real* URL that also
+carries its own authorization. The token is not a session credential: it
+authorises exactly one (quote_id, kind, attachment_id) triple and expires
+in minutes.
+
+Format: ``<expiry-unix>.<hex-hmac>`` over ``"{quote_id}:{kind}:{attachment_id}:{expiry}"``.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import hmac
+import time
+import uuid
+
+from app.config import settings
+
+# پیش‌نمایش کوتاه‌عمر است — فقط برای باز شدن مودال، نه اشتراک‌گذاری لینک
+DEFAULT_TTL_SECONDS = 300
+
+
+def _secret() -> bytes:
+    """Key for the HMAC. Reuses existing secrets so no new config is needed."""
+    base = (
+        settings.CASDOOR_CLIENT_SECRET
+        or settings.MINIO_SECRET_KEY
+        or "procurement-preview-fallback"
+    )
+    return base.encode("utf-8")
+
+
+def _sign(quote_id: uuid.UUID, kind: str, attachment_id: uuid.UUID, expiry: int) -> str:
+    msg = f"{quote_id}:{kind}:{attachment_id}:{expiry}".encode("utf-8")
+    return hmac.new(_secret(), msg, hashlib.sha256).hexdigest()
+
+
+def make_preview_token(
+    quote_id: uuid.UUID, kind: str, attachment_id: uuid.UUID, ttl: int = DEFAULT_TTL_SECONDS
+) -> str:
+    expiry = int(time.time()) + ttl
+    return f"{expiry}.{_sign(quote_id, kind, attachment_id, expiry)}"
+
+
+def verify_preview_token(
+    token: str, quote_id: uuid.UUID, kind: str, attachment_id: uuid.UUID
+) -> bool:
+    """True when the token is well-formed, unexpired and matches this file."""
+    if not token or "." not in token:
+        return False
+    expiry_raw, signature = token.split(".", 1)
+    try:
+        expiry = int(expiry_raw)
+    except ValueError:
+        return False
+    if expiry < int(time.time()):
+        return False
+    expected = _sign(quote_id, kind, attachment_id, expiry)
+    return hmac.compare_digest(expected, signature)
diff --git a/docker-compose.yml b/docker-compose.yml
index 9dd4694..b2187e0 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -289,6 +289,11 @@ services:
         VITE_OPENPANEL_CLIENT_ID: ${OPENPANEL_CLIENT_ID:-}
         VITE_SENTRY_DSN: ${SENTRY_DSN_FRONTEND:-}
     container_name: procurement-frontend
+    # از entrypoint پیش‌فرض image nginx رد می‌شویم: آن اسکریپت `apk manifest`
+    # اجرا می‌کند و اگر دسترسی به مخزن بسته‌ها نباشد بی‌نهایت معلق می‌ماند
+    # (سرویس بالا نمی‌آید و traefik خطای 502 می‌دهد). کانفیگ ما مستقل است و
+    # نیازی به آن اسکریپت‌ها ندارد.
+    entrypoint: ["nginx", "-g", "daemon off;"]
 
     labels:
       - traefik.enable=true
diff --git a/frontend/nginx.conf b/frontend/nginx.conf
index 59228a6..62473ce 100644
--- a/frontend/nginx.conf
+++ b/frontend/nginx.conf
@@ -29,6 +29,26 @@ server {
         proxy_set_header X-Forwarded-Proto $scheme;
     }
 
+    # MIME types: the pdf.js worker ships as .mjs, and a browser REFUSES to
+    # start a module worker served as application/octet-stream (nginx's
+    # default for unknown extensions) — which crashes the PDF preview page.
+    # Declared explicitly rather than relying on the system mime.types.
+    types {
+        text/javascript    mjs js;
+        text/css           css;
+        text/html          html;
+        image/svg+xml      svg;
+        image/png          png;
+        image/jpeg         jpg jpeg;
+        image/webp         webp;
+        image/x-icon       ico;
+        font/woff2         woff2;
+        font/woff          woff;
+        application/json   json;
+        application/pdf    pdf;
+        application/wasm   wasm;
+    }
+
     # SPA fallback — all client-side routes go to index.html
     location / {
         try_files $uri $uri/ /index.html;
diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index c95d19b..f7d6e03 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -23,6 +23,7 @@
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
         "lucide-react": "^1.30.0",
+        "pdfjs-dist": "^4.10.38",
         "react": "^19.2.8",
         "react-dom": "^19.2.8",
         "react-hook-form": "^7.85.0",
@@ -174,6 +175,256 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@napi-rs/canvas": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas/-/canvas-0.1.100.tgz",
+      "integrity": "sha512-xglYA6q3XO5P3BNJYxVZ1IV7DLVjp1Py6nwag88YntrS+3vKHyYcMqXVS4ZztJmwz2uGvz1FWhI/4LgbR5uQDA==",
+      "license": "MIT",
+      "optional": true,
+      "workspaces": [
+        "e2e/*"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      },
+      "optionalDependencies": {
+        "@napi-rs/canvas-android-arm64": "0.1.100",
+        "@napi-rs/canvas-darwin-arm64": "0.1.100",
+        "@napi-rs/canvas-darwin-x64": "0.1.100",
+        "@napi-rs/canvas-linux-arm-gnueabihf": "0.1.100",
+        "@napi-rs/canvas-linux-arm64-gnu": "0.1.100",
+        "@napi-rs/canvas-linux-arm64-musl": "0.1.100",
+        "@napi-rs/canvas-linux-riscv64-gnu": "0.1.100",
+        "@napi-rs/canvas-linux-x64-gnu": "0.1.100",
+        "@napi-rs/canvas-linux-x64-musl": "0.1.100",
+        "@napi-rs/canvas-win32-arm64-msvc": "0.1.100",
+        "@napi-rs/canvas-win32-x64-msvc": "0.1.100"
+      }
+    },
+    "node_modules/@napi-rs/canvas-android-arm64": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-android-arm64/-/canvas-android-arm64-0.1.100.tgz",
+      "integrity": "sha512-hjhCKhntPv9+t4ckHymdx0phYNcVW+GKQR6Lzw2zE+pOVjOplSmtx9nNNknTjbEDLcuLZqA1y8ufKg1XfgftzQ==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "android"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-darwin-arm64": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-darwin-arm64/-/canvas-darwin-arm64-0.1.100.tgz",
+      "integrity": "sha512-2PcswRaC7Ly645DGt88///zuFDhJxJYdKAs1uU3mfk1atYkXufgcgLfBpk6Tm12nCQBaNt1wpybuPZ4qOhTo8A==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-darwin-x64": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-darwin-x64/-/canvas-darwin-x64-0.1.100.tgz",
+      "integrity": "sha512-ePNZtj7pNIva/siZMg+HmbeozkIjqUIYdoymH8HaA3qK7LfzFN4WMBM8G6HQ9ZC+H3+Dnn5pqtiXpgLykaPOhw==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-arm-gnueabihf": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-linux-arm-gnueabihf/-/canvas-linux-arm-gnueabihf-0.1.100.tgz",
+      "integrity": "sha512-d5cDB48oWFGU8/XPhUOFAlySgb/VAu7D+s8fi55K1Pcfg8aPplHWqMgibhVLU8ky7Pyg/fuiVLz4Nf3JrSTuUA==",
+      "cpu": [
+        "arm"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-arm64-gnu": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-linux-arm64-gnu/-/canvas-linux-arm64-gnu-0.1.100.tgz",
+      "integrity": "sha512-rDxgxRu69RvDlX/bh9o22DxLsGr8EqsNgotL9+RwQE1S0b0cqeatqsw6aW45mukm0B42DIAaAacKaYQ8cqS1nw==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-arm64-musl": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-linux-arm64-musl/-/canvas-linux-arm64-musl-0.1.100.tgz",
+      "integrity": "sha512-K3mDW66N+xT2/V439u1alFANiBUjdEx2gLiNYnCmUsva5jZMxWTjafBYwTzYK+EMFMHrUoabuU+T1BIP5CgbYQ==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-riscv64-gnu": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-linux-riscv64-gnu/-/canvas-linux-riscv64-gnu-0.1.100.tgz",
+      "integrity": "sha512-mooqUBTIsccZpnoQC4NgrC1v6C1vof39etLNMnBwCY+p0gajWJvAHLGQ6g/gGyS5YrpDW+GefSN4+Cvcr08UWw==",
+      "cpu": [
+        "riscv64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-x64-gnu": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-linux-x64-gnu/-/canvas-linux-x64-gnu-0.1.100.tgz",
+      "integrity": "sha512-1eCvkDCazm7FFhsT7DfGOdSaHgZVK3bt/dSBl5EWHOWmnz+I7j8tPseJqqD81NF+MH21jKUK4wQSDjN0mdhnTg==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-linux-x64-musl": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-linux-x64-musl/-/canvas-linux-x64-musl-0.1.100.tgz",
+      "integrity": "sha512-20arT6lnI19S68qNlii73TSEDbECNgzMz2EpldC1V3mZFuRkeujXkcebRk0LRJe9SEUAooYiLokfMViY8IX7yA==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "linux"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-win32-arm64-msvc": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-win32-arm64-msvc/-/canvas-win32-arm64-msvc-0.1.100.tgz",
+      "integrity": "sha512-DZFFT1wIAg37LJw37yhMRFfjATd3vTQzjZ1Yki8u2vhO6Hi5VE6BVaGQ1aaDu7xb4iMErz+9EOwjpS7xcxFeBw==",
+      "cpu": [
+        "arm64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
+    "node_modules/@napi-rs/canvas-win32-x64-msvc": {
+      "version": "0.1.100",
+      "resolved": "https://registry.npmmirror.com/@napi-rs/canvas-win32-x64-msvc/-/canvas-win32-x64-msvc-0.1.100.tgz",
+      "integrity": "sha512-MyT1j3mHC2+Lu4pBi9mKyMJhtP6U7k7EldY7sj/uS5gJA65gTXt8MefJQXLJo5d/vZbuWmfxzkEUNc/urV3pHA==",
+      "cpu": [
+        "x64"
+      ],
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "win32"
+      ],
+      "engines": {
+        "node": ">= 10"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Brooooooklyn"
+      }
+    },
     "node_modules/@openpanel/sdk": {
       "version": "1.3.1",
       "resolved": "https://registry.npmjs.org/@openpanel/sdk/-/sdk-1.3.1.tgz",
@@ -2299,6 +2550,18 @@
         }
       }
     },
+    "node_modules/pdfjs-dist": {
+      "version": "4.10.38",
+      "resolved": "https://registry.npmmirror.com/pdfjs-dist/-/pdfjs-dist-4.10.38.tgz",
+      "integrity": "sha512-/Y3fcFrXEAsMjJXeL9J8+ZG9U01LbuWaYypvDW2ycW1jL269L3js3DVBjDJ0Up9Np1uqDXsDrRihHANhZOlwdQ==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=20"
+      },
+      "optionalDependencies": {
+        "@napi-rs/canvas": "^0.1.65"
+      }
+    },
     "node_modules/picocolors": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
diff --git a/frontend/package.json b/frontend/package.json
index a3c5697..399a320 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -10,7 +10,6 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "@sentry/react": "^10.0.0",
     "@dnd-kit/core": "^6.3.1",
     "@dnd-kit/utilities": "^3.2.2",
     "@hookform/resolvers": "3.10",
@@ -20,11 +19,13 @@
     "@radix-ui/react-label": "^2.1.15",
     "@radix-ui/react-select": "^2.3.7",
     "@radix-ui/react-slot": "^1.3.3",
+    "@sentry/react": "^10.0.0",
     "@tailwindcss/vite": "^4.3.3",
     "@tanstack/react-query": "^5.101.4",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^1.30.0",
+    "pdfjs-dist": "^4.10.38",
     "react": "^19.2.8",
     "react-dom": "^19.2.8",
     "react-hook-form": "^7.85.0",
diff --git a/frontend/src/components/FileList.tsx b/frontend/src/components/FileList.tsx
index 439163b..96b5a7f 100644
--- a/frontend/src/components/FileList.tsx
+++ b/frontend/src/components/FileList.tsx
@@ -1,7 +1,8 @@
-import { useEffect, useRef, useState } from "react";
+import { useRef, useState } from "react";
 import { toast } from "sonner";
-import { Eye, Download, Trash2, X, FileText, Image as ImageIcon, ExternalLink } from "lucide-react";
+import { Eye, Download, Trash2, FileText, Image as ImageIcon } from "lucide-react";
 import type { Attachment } from "../lib/types";
+import { FilePreviewModal, isImageFile, isPdfFile } from "./FilePreviewModal";
 
 export interface FileListProps {
   files: Attachment[];
@@ -18,14 +19,6 @@ export interface FileListProps {
   label?: string;
 }
 
-const isImageFile = (name: string = "") => {
-  return /\.(jpe?g|png|webp|gif|svg|bmp)$/i.test(name.toLowerCase());
-};
-
-const isPdfFile = (name: string = "") => {
-  return /\.pdf$/i.test(name.toLowerCase());
-};
-
 // مدیریت چند فاکتور: آپلود مستقیم، پیش‌نمایش آنلاین تصویر/PDF و دانلود
 export function FileList({
   files,
@@ -39,21 +32,6 @@ export function FileList({
   const inputRef = useRef<HTMLInputElement | null>(null);
   const [previewItem, setPreviewItem] = useState<{ url: string; name: string } | null>(null);
   const [loadingPreview, setLoadingPreview] = useState<string | null>(null);
-  // آخرین objectURL ساخته‌شده — برای آزادسازی مطمئن (جلوگیری از نشت حافظه)
-  const previewUrlRef = useRef<string | null>(null);
-
-  const revokePreviewUrl = () => {
-    if (previewUrlRef.current) {
-      try {
-        URL.revokeObjectURL(previewUrlRef.current);
-      } catch {
-        /* آدرس نامعتبر — نادیده بگیر */
-      }
-      previewUrlRef.current = null;
-    }
-  };
-
-  useEffect(() => revokePreviewUrl, []);
 
   const remove = (i: number) => {
     const removed = files[i];
@@ -76,7 +54,8 @@ export function FileList({
     if (added.length) onChange([...files, ...added]);
   };
 
-  // پیش‌نمایش: بایت‌ها را با توکن می‌گیریم و به شکل objectURL نشان می‌دهیم
+  // پیش‌نمایش: یک URL امضاشده‌ی کوتاه‌عمر می‌گیریم (نه blob) تا
+  // دانلودمنیجرها آن را شکار نکنند و <iframe>/<img> درست بارگذاری شود.
   const handleOpenPreview = async (inv: Attachment) => {
     if (!loadPreview) return;
     if (!inv.id) {
@@ -86,8 +65,6 @@ export function FileList({
     setLoadingPreview(inv.id);
     try {
       const url = await loadPreview(inv);
-      revokePreviewUrl();
-      previewUrlRef.current = url;
       setPreviewItem({ url, name: inv.name });
     } catch (err) {
       toast.error(err instanceof Error ? err.message : "بارگذاری پیش‌نمایش ناموفق بود");
@@ -96,10 +73,7 @@ export function FileList({
     }
   };
 
-  const closePreview = () => {
-    revokePreviewUrl();
-    setPreviewItem(null);
-  };
+  const closePreview = () => setPreviewItem(null);
 
   return (
     <div className="space-y-2">
@@ -201,94 +175,9 @@ export function FileList({
         </button>
       </div>
 
-      {/* پنجره مودال پیش‌نمایش (Preview Modal) */}
+      {/* مودال پیش‌نمایش — کامپوننت مشترک با کارت پیشنهاد در داشبورد */}
       {previewItem && (
-        <div
-          className="fixed inset-0 z-[80] flex items-center justify-center bg-black/60 p-3 sm:p-5 backdrop-blur-xs animate-in fade-in duration-200"
-          onClick={closePreview}
-        >
-          <div
-            className="flex flex-col w-full max-w-4xl max-h-[90vh] rounded-2xl border border-gray-200 bg-white shadow-2xl overflow-hidden"
-            onClick={(e) => e.stopPropagation()}
-          >
-            {/* هدر پیش‌نمایش */}
-            <div className="flex items-center justify-between border-b border-gray-100 px-4 py-3 bg-white">
-              <div className="flex items-center gap-2 min-w-0">
-                {isImageFile(previewItem.name) ? (
-                  <ImageIcon className="h-4 w-4 shrink-0 text-blue-600" />
-                ) : (
-                  <FileText className="h-4 w-4 shrink-0 text-rose-600" />
-                )}
-                <span className="text-xs sm:text-sm font-bold text-gray-900 truncate">
-                  {previewItem.name}
-                </span>
-              </div>
-
-              <div className="flex items-center gap-1.5 shrink-0">
-                <a
-                  href={previewItem.url}
-                  download={previewItem.name}
-                  className="inline-flex items-center gap-1 rounded-lg border border-gray-200 bg-white px-2.5 py-1 text-xs font-semibold text-gray-700 hover:bg-gray-50 hover:text-gray-900 transition-colors shadow-2xs"
-                  title="دانلود فاکتور"
-                >
-                  <Download className="h-3.5 w-3.5" />
-                  <span className="hidden xs:inline">دانلود فاکتور</span>
-                </a>
-
-                <a
-                  href={previewItem.url}
-                  target="_blank"
-                  rel="noreferrer"
-                  className="flex h-7 w-7 items-center justify-center rounded-lg border border-gray-200 text-gray-600 hover:bg-gray-50 hover:text-gray-900 transition-colors shadow-2xs"
-                  title="باز کردن در برگه جدید"
-                >
-                  <ExternalLink className="h-3.5 w-3.5" />
-                </a>
-
-                <button
-                  type="button"
-                  onClick={closePreview}
-                  className="flex h-7 w-7 items-center justify-center rounded-lg text-gray-400 hover:bg-gray-100 hover:text-gray-700 transition-colors ms-1"
-                  title="بستن"
-                >
-                  <X className="h-4 w-4" />
-                </button>
-              </div>
-            </div>
-
-            {/* بدنه نمایش فایل */}
-            <div className="flex-1 overflow-auto p-3 sm:p-4 bg-gray-50/70 flex items-center justify-center min-h-[300px]">
-              {isImageFile(previewItem.name) ? (
-                <img
-                  src={previewItem.url}
-                  alt={previewItem.name}
-                  className="max-h-[75vh] w-auto max-w-full rounded-lg object-contain shadow-xs border border-gray-200 bg-white"
-                />
-              ) : isPdfFile(previewItem.name) ? (
-                <iframe
-                  src={previewItem.url}
-                  title={previewItem.name}
-                  className="h-[75vh] w-full rounded-lg border border-gray-200 bg-white shadow-xs"
-                />
-              ) : (
-                <div className="flex flex-col items-center justify-center gap-3 p-8 text-center bg-white rounded-xl border border-gray-200 shadow-xs">
-                  <FileText className="h-12 w-12 text-gray-400" />
-                  <div className="text-xs text-gray-600">
-                    امکان نمایش پیش‌نمایش زنده برای این فرمت فایل وجود ندارد.
-                  </div>
-                  <a
-                    href={previewItem.url}
-                    download={previewItem.name}
-                    className="inline-flex items-center gap-1.5 rounded-lg bg-blue-600 px-3.5 py-1.5 text-xs font-semibold text-white hover:bg-blue-700 transition-colors"
-                  >
-                    <Download className="h-3.5 w-3.5" />
-                    دانلود فایل
-                  </a>
-                </div>
-              )}
-            </div>
-          </div>
-        </div>
+        <FilePreviewModal url={previewItem.url} name={previewItem.name} onClose={closePreview} />
       )}
     </div>
   );
diff --git a/frontend/src/components/FilePreviewModal.tsx b/frontend/src/components/FilePreviewModal.tsx
new file mode 100644
index 0000000..9bcb3b7
--- /dev/null
+++ b/frontend/src/components/FilePreviewModal.tsx
@@ -0,0 +1,148 @@
+import { useState } from "react";
+import { PdfCanvas } from "./PdfCanvas";
+import { X, FileText, Image as ImageIcon, ExternalLink } from "lucide-react";
+
+export const isImageFile = (name: string = "") => {
+  return /\.(jpe?g|png|webp|gif|svg|bmp)$/i.test(name.toLowerCase());
+};
+
+export const isPdfFile = (name: string = "") => {
+  return /\.pdf$/i.test(name.toLowerCase());
+};
+
+/**
+ * آیا مرورگر می‌تواند PDF را درون‌خطی نشان دهد؟
+ *
+ * دسکتاپ: بله (نمایشگر بومی) → <iframe> کافی است و بهترین تجربه را دارد.
+ * شبیه‌سازی موبایل/اندروید: پلاگین PDF وجود ندارد؛ <iframe> به دانلود
+ * منتهی می‌شود، پس آنجا pdf.js استفاده می‌کنیم.
+ */
+export function canRenderPdfNatively(): boolean {
+  if (typeof navigator === "undefined") return true;
+  const ua = navigator.userAgent || "";
+  const mobile = /Android|iPhone|iPad|iPod|Mobile/i.test(ua);
+  // pdfViewerEnabled در Chromium/Firefox وجود دارد و دقیق‌ترین معیار است
+  const pdfViewer = (navigator as { pdfViewerEnabled?: boolean }).pdfViewerEnabled;
+  if (typeof pdfViewer === "boolean") return pdfViewer && !mobile;
+  return !mobile;
+}
+
+export interface FilePreviewModalProps {
+  // آدرس امضاشده‌ی کوتاه‌عمر — چون <img>/<iframe> نمی‌توانند هدر توکن بفرستند
+  url: string;
+  name: string;
+  onClose: () => void;
+}
+
+/**
+ * مودال پیش‌نمایش فایل — مشترک بین لیست پیوست‌ها (FileList) و کارت پیشنهاد
+ * در داشبورد. تصویر با <img> و PDF با pdf.js روی canvas رسم می‌شود (بدون
+ * وابستگی به پلاگین PDF مرورگر، که در شبیه‌سازی موبایل وجود ندارد)؛ سایر
+ * فرمت‌ها فقط دکمه‌ی دانلود دارند.
+ */
+export function FilePreviewModal({ url, name, onClose }: FilePreviewModalProps) {
+  return (
+    <div
+      className="fixed inset-0 z-[80] flex items-center justify-center bg-black/60 p-3 sm:p-5 backdrop-blur-xs animate-in fade-in duration-200"
+      onClick={onClose}
+    >
+      <div
+        className="flex flex-col w-full max-w-4xl max-h-[90vh] rounded-2xl border border-gray-200 bg-white shadow-2xl overflow-hidden"
+        onClick={(e) => e.stopPropagation()}
+      >
+        {/* هدر پیش‌نمایش */}
+        <div className="flex items-center justify-between border-b border-gray-100 px-4 py-3 bg-white">
+          <div className="flex items-center gap-2 min-w-0">
+            {isImageFile(name) ? (
+              <ImageIcon className="h-4 w-4 shrink-0 text-blue-600" />
+            ) : (
+              <FileText className="h-4 w-4 shrink-0 text-rose-600" />
+            )}
+            <span className="text-xs sm:text-sm font-bold text-gray-900 truncate">{name}</span>
+          </div>
+
+          <div className="flex items-center gap-1.5 shrink-0">
+            <a
+              href={url}
+              target="_blank"
+              rel="noreferrer"
+              className="flex h-7 w-7 items-center justify-center rounded-lg border border-gray-200 text-gray-600 hover:bg-gray-50 hover:text-gray-900 transition-colors shadow-2xs"
+              title="باز کردن در برگه جدید"
+            >
+              <ExternalLink className="h-3.5 w-3.5" />
+            </a>
+
+            <button
+              type="button"
+              onClick={onClose}
+              className="flex h-7 w-7 items-center justify-center rounded-lg text-gray-400 hover:bg-gray-100 hover:text-gray-700 transition-colors ms-1"
+              title="بستن"
+            >
+              <X className="h-4 w-4" />
+            </button>
+          </div>
+        </div>
+
+        {/* بدنه نمایش فایل */}
+        <div className="flex-1 overflow-auto p-3 sm:p-4 bg-gray-50/70 flex items-center justify-center min-h-[300px]">
+          {isImageFile(name) ? (
+            <img
+              src={url}
+              alt={name}
+              className="max-h-[75vh] w-auto max-w-full rounded-lg object-contain shadow-xs border border-gray-200 bg-white"
+            />
+          ) : isPdfFile(name) ? (
+            // روی دسکتاپ نمایشگر بومی مرورگر بهترین نتیجه را می‌دهد؛ در
+            // شبیه‌سازی موبایل پلاگین PDF وجود ندارد، پس آنجا pdf.js روی
+            // canvas رسم می‌کند. انتخاب در زمان اجرا با تشخیص قابلیت.
+            canRenderPdfNatively() ? (
+              <iframe
+                src={url}
+                title={name}
+                className="h-[75vh] w-full rounded-lg border border-gray-200 bg-white shadow-xs"
+              />
+            ) : (
+              <PdfCanvas url={url} className="w-full" />
+            )
+          ) : (
+            <div className="flex flex-col items-center justify-center gap-3 p-8 text-center bg-white rounded-xl border border-gray-200 shadow-xs">
+              <FileText className="h-12 w-12 text-gray-400" />
+              <div className="text-xs text-gray-600">
+                امکان نمایش پیش‌نمایش زنده برای این فرمت فایل وجود ندارد.
+              </div>
+            </div>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+}
+
+/**
+ * هوک مدیریت پیش‌نمایش: بارگذاری blob احراز هویت‌شده + آزادسازی objectURL.
+ * خروجی برای رندر <FilePreviewModal> آماده است.
+ */
+/**
+ * هوک مدیریت پیش‌نمایش: گرفتن URL امضاشده و نگه‌داشتن آن برای مودال.
+ * URL یک آدرس واقعی است (نه blob) تا دانلودمنیجرها آن را نشکنند؛ پس
+ * نیازی به آزادسازی objectURL نیست.
+ */
+export function useFilePreview(load: (id: string, name: string) => Promise<string>) {
+  const [item, setItem] = useState<{ url: string; name: string } | null>(null);
+  const [loadingId, setLoadingId] = useState<string | null>(null);
+
+  const open = async (id: string, name: string) => {
+    if (!id) return;
+    setLoadingId(id);
+    try {
+      const url = await load(id, name);
+      setItem({ url, name });
+    } finally {
+      setLoadingId(null);
+    }
+  };
+
+  const close = () => setItem(null);
+
+  return { item, loadingId, open, close };
+}
diff --git a/frontend/src/components/PdfCanvas.tsx b/frontend/src/components/PdfCanvas.tsx
new file mode 100644
index 0000000..08fe5bf
--- /dev/null
+++ b/frontend/src/components/PdfCanvas.tsx
@@ -0,0 +1,125 @@
+import { useEffect, useRef, useState } from "react";
+
+/**
+ * نمایشگر PDF با pdf.js (canvas) به‌جای <iframe>.
+ *
+ * چرا: کروم در حالت شبیه‌سازی موبایل (F12) پلاگین PDF درون‌خطی ندارد، پس
+ * <iframe src="...pdf"> را به‌جای نمایش، دانلود می‌کند — که دانلودمنیجرها
+ * شکارش می‌کنند و پیش‌نمایش خالی می‌ماند. با رسم روی canvas هیچ ناوبری‌ای
+ * به آدرس فایل انجام نمی‌شود، پس نه به پلاگین مرورگر وابسته‌ایم و نه چیزی
+ * برای دانلودمنیجر باقی می‌ماند.
+ */
+interface PdfCanvasProps {
+  url: string;
+  className?: string;
+}
+
+export function PdfCanvas({ url, className }: PdfCanvasProps) {
+  const canvasRef = useRef<HTMLCanvasElement | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [pageCount, setPageCount] = useState(0);
+
+  useEffect(() => {
+    let cancelled = false;
+    let doc: { destroy: () => void } | null = null;
+
+    (async () => {
+      setLoading(true);
+      setError(null);
+      try {
+        // بارگذاری تنبل: pdf.js فقط وقتی پیش‌نمایش PDF باز می‌شود دانلود می‌شود
+        const pdfjs = await import("pdfjs-dist");
+        // فقط workerSrc ست می‌شود — ست‌کردن هم‌زمان workerPort باعث تعارض
+        // می‌شد و بارگذاری سند در حلقه گیر می‌کرد («در حال بارگذاری…»).
+        // فایل worker با پسوند .mjs سرو می‌شود و nginx آن را
+        // text/javascript اعلام می‌کند (وگرنه مرورگر worker را رد می‌کند).
+        const workerUrl = (await import("pdfjs-dist/build/pdf.worker.min.mjs?url")).default;
+        pdfjs.GlobalWorkerOptions.workerSrc = workerUrl;
+
+        // بایت‌ها را خودمان با fetch می‌گیریم و به pdf.js به‌صورت داده
+        // می‌دهیم، به‌جای اینکه pdf.js خودش آدرس را بگیرد. دلیل: دانلودمنیجر
+        // (IDM) درخواست pdf.js به آدرس PDF را می‌رباید و با 204 برمی‌گرداند
+        // («Unexpected server response (204)»). با داده‌ی درون‌حافظه هیچ
+        // درخواست قابل‌ربودنی برای دانلودمنیجر باقی نمی‌ماند.
+        const res = await fetch(url, { credentials: "omit" });
+        if (!res.ok) throw new Error(`دریافت فایل ناموفق بود (${res.status})`);
+        const bytes = new Uint8Array(await res.arrayBuffer());
+
+        const task = pdfjs.getDocument({ data: bytes });
+        // اگر worker/شبکه در دسترس نباشد، به‌جای چرخ «در حال بارگذاری…»
+        // بی‌پایان، خطای قابل‌فهم نشان بده.
+        const loaded = await Promise.race([
+          task.promise,
+          new Promise<never>((_, reject) =>
+            setTimeout(() => reject(new Error("زمان بارگذاری PDF به پایان رسید")), 20000),
+          ),
+        ]);
+        doc = loaded as unknown as { destroy: () => void };
+        if (cancelled) return;
+
+        setPageCount(loaded.numPages);
+
+        // فعلاً صفحه‌ی اول — برای پیش‌نمایشِ سریع کافی است
+        const page = await loaded.getPage(1);
+        if (cancelled) return;
+
+        const canvas = canvasRef.current;
+        if (!canvas) return;
+
+        // مقیاس بر اساس عرض ظرف، با در نظر گرفتن devicePixelRatio برای وضوح
+        const containerWidth = canvas.parentElement?.clientWidth || 800;
+        const baseViewport = page.getViewport({ scale: 1 });
+        const dpr = window.devicePixelRatio || 1;
+        const scale = Math.min((containerWidth - 2) / baseViewport.width, 2) * dpr;
+        const viewport = page.getViewport({ scale });
+
+        canvas.width = Math.floor(viewport.width);
+        canvas.height = Math.floor(viewport.height);
+        canvas.style.width = `${Math.floor(viewport.width / dpr)}px`;
+        canvas.style.height = `${Math.floor(viewport.height / dpr)}px`;
+
+        const ctx = canvas.getContext("2d");
+        if (!ctx) return;
+        await page.render({ canvasContext: ctx, viewport }).promise;
+        if (!cancelled) setLoading(false);
+      } catch (err) {
+        if (!cancelled) {
+          setLoading(false);
+          setError(err instanceof Error ? err.message : "نمایش PDF ناموفق بود");
+        }
+      }
+    })();
+
+    return () => {
+      cancelled = true;
+      try {
+        doc?.destroy();
+      } catch {
+        /* نادیده بگیر */
+      }
+    };
+  }, [url]);
+
+  return (
+    <div className={className}>
+      {loading && !error && (
+        <div className="flex items-center justify-center p-8 text-xs text-gray-500">در حال بارگذاری…</div>
+      )}
+      {error ? (
+        <div className="flex flex-col items-center justify-center gap-3 p-8 text-center">
+          <div className="text-xs text-gray-600">نمایش پیش‌نمایش ممکن نشد: {error}</div>
+        </div>
+      ) : (
+        <>
+          <canvas ref={canvasRef} className="mx-auto block max-w-full rounded-lg border border-gray-200 bg-white shadow-xs" />
+          {pageCount > 1 && (
+            <div className="mt-2 text-center text-[11px] text-gray-500">
+              صفحه ۱ از {pageCount}
+            </div>
+          )}
+        </>
+      )}
+    </div>
+  );
+}
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 969e685..9f9fb63 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -1320,18 +1320,16 @@ export const api = {
     },
     // آدرس blob احراز هویت‌شده برای پیش‌نمایش (تصویر/PDF در مودال).
     // تگ‌های <img>/<iframe>/<a href> توکن نمی‌فرستند، پس بایت‌ها را با توکن
-    // می‌گیریم و یک objectURL محلی برمی‌گردانیم. آزادسازی با revokeBlobUrl.
-    blobUrl: async (quoteId: string, kind: FileKind, id: string): Promise<string> => {
-      let res: Response;
-      const path = `/quotes/${quoteId}/${kind}/${id}`;
-      try {
-        res = await fetch(BASE_URL + path, { headers: authHeaders() });
-      } catch {
-        throw new ApiError("اتصال به سرور برقرار نشد — آیا بک‌اند در دسترس است؟", 0);
-      }
-      handle401(path, res);
-      if (!res.ok) throw new ApiError(faHttpError(res.status, "خطای سرور"), res.status);
-      return URL.createObjectURL(await res.blob());
+    // آدرس پیش‌نمایش احراز هویت‌شده برای <iframe>/<img>.
+    // این‌ها نمی‌توانند هدر Authorization بفرستند، پس بک‌اند یک توکن
+    // امضاشده‌ی کوتاه‌عمر در کوئری می‌دهد. عمداً blob ساخته نمی‌شود:
+    // دانلودمنیجرها (IDM) blob را شکار می‌کنند و فایل ۰ بایتی می‌سازند،
+    // در حالی که این یک URL واقعی است و درست بارگذاری می‌شود.
+    previewUrl: async (quoteId: string, kind: FileKind, id: string): Promise<string> => {
+      const res = await getData<{ url: string; token: string }>(
+        `/quotes/${quoteId}/preview-url/${kind}/${id}`,
+      );
+      return BASE_URL + res.url;
     },
   },
 
diff --git a/frontend/src/pages/Dashboard/AcceptModal.tsx b/frontend/src/pages/Dashboard/AcceptModal.tsx
index 7d31a7d..df384e0 100644
--- a/frontend/src/pages/Dashboard/AcceptModal.tsx
+++ b/frontend/src/pages/Dashboard/AcceptModal.tsx
@@ -407,7 +407,7 @@ export function AcceptModal({ quoteId, onClose }: AcceptModalProps) {
                     )
                   }
                   onDownload={(a) => api.files.download(q.id, "invoice", a.id!, a.name)}
-                  loadPreview={(a) => api.files.blobUrl(q.id, "invoice", a.id!)}
+                  loadPreview={(a) => api.files.previewUrl(q.id, "invoice", a.id!)}
                 />
               </div>
 
@@ -426,7 +426,7 @@ export function AcceptModal({ quoteId, onClose }: AcceptModalProps) {
                     )
                   }
                   onDownload={(a) => api.files.download(q.id, "proforma", a.id!, a.name)}
-                  loadPreview={(a) => api.files.blobUrl(q.id, "proforma", a.id!)}
+                  loadPreview={(a) => api.files.previewUrl(q.id, "proforma", a.id!)}
                   label="افزودن پیش‌فاکتور"
                 />
               </div>
diff --git a/frontend/src/pages/Dashboard/EditModal.tsx b/frontend/src/pages/Dashboard/EditModal.tsx
index 4dc70ff..5c52ad1 100644
--- a/frontend/src/pages/Dashboard/EditModal.tsx
+++ b/frontend/src/pages/Dashboard/EditModal.tsx
@@ -892,7 +892,7 @@ export function EditModal({ quoteId, onClose }: EditModalProps) {
                       )
                     }
                     onDownload={(a) => api.files.download(q.id, "invoice", a.id!, a.name)}
-                    loadPreview={(a) => api.files.blobUrl(q.id, "invoice", a.id!)}
+                    loadPreview={(a) => api.files.previewUrl(q.id, "invoice", a.id!)}
                   />
                 </div>
               </div>
diff --git a/frontend/src/pages/Dashboard/QuoteDetail.tsx b/frontend/src/pages/Dashboard/QuoteDetail.tsx
index 9063b65..9be009a 100644
--- a/frontend/src/pages/Dashboard/QuoteDetail.tsx
+++ b/frontend/src/pages/Dashboard/QuoteDetail.tsx
@@ -13,6 +13,7 @@ import { fmtDate, fmtDateTime, fmtNum } from "../../lib/formatters";
 import { groupCommas } from "../../lib/numutil";
 import { FlowDiagram, type FlowRefs } from "./FlowDiagram";
 import { itemProjects } from "../../lib/quoteUtils";
+import { FilePreviewModal, useFilePreview } from "../../components/FilePreviewModal";
 
 export interface QuoteDetailProps {
   store: Store;
@@ -25,6 +26,15 @@ export function QuoteDetail({ store, q }: QuoteDetailProps) {
   const [flowRefs] = useState<FlowRefs>(() => ({ items: new Map(), termsheets: new Map() }));
   const [bump, setBump] = useState(0);
 
+  // پیش‌نمایش پیوست‌ها: کلیک روی نام فایل، فایل را نشان می‌دهد (نه دانلود).
+  // بایت‌ها با توکن گرفته می‌شوند چون <img>/<iframe> نمی‌توانند هدر بفرستند.
+  // کلید با پیشوند نوع پیوست ساخته می‌شود تا نوعش گم نشود.
+  const preview = useFilePreview((key, name) => {
+    const [kind, id] = key.split(":") as ["invoice" | "proforma", string];
+    void name;
+    return api.files.previewUrl(q.id, kind, id);
+  });
+
   useEffect(() => {
     // بعد از نشستن layout (فونت/تصویر) خطوط دوباره رسم شوند
     const t = setTimeout(() => setBump((b) => b + 1), 350);
@@ -144,31 +154,35 @@ export function QuoteDetail({ store, q }: QuoteDetailProps) {
   attachments.proformas.forEach((pf, i) => {
     if (!pf.id) return;
     attachParts.push(
-      <button
-        key={"pf" + i}
-        type="button"
-        className="detail-link"
-        title="دانلود پیش‌فاکتور"
-        onClick={() => api.files.download(q.id, "proforma", pf.id!, pf.name)}
-      >
-        <Paperclip className="me-1 inline h-3 w-3" />
-        پیش‌فاکتور: {pf.name}
-      </button>,
+      <span key={"pf" + i} className="inline-flex items-center">
+        <button
+          type="button"
+          className="detail-link"
+          title="مشاهده پیش‌فاکتور"
+          disabled={preview.loadingId === `proforma:${pf.id}`}
+          onClick={() => void preview.open(`proforma:${pf.id}`, pf.name)}
+        >
+          <Paperclip className="me-1 inline h-3 w-3" />
+          پیش‌فاکتور: {pf.name}
+        </button>
+      </span>,
     );
   });
   attachments.invoices.forEach((inv, i) => {
     if (!inv.id) return;
     attachParts.push(
-      <button
-        key={"inv" + i}
-        type="button"
-        className="detail-link"
-        title="دانلود فاکتور"
-        onClick={() => api.files.download(q.id, "invoice", inv.id!, inv.name)}
-      >
-        <Paperclip className="me-1 inline h-3 w-3" />
-        فاکتور اصلی: {inv.name}
-      </button>,
+      <span key={"inv" + i} className="inline-flex items-center">
+        <button
+          type="button"
+          className="detail-link"
+          title="مشاهده فاکتور"
+          disabled={preview.loadingId === `invoice:${inv.id}`}
+          onClick={() => void preview.open(`invoice:${inv.id}`, inv.name)}
+        >
+          <Paperclip className="me-1 inline h-3 w-3" />
+          فاکتور اصلی: {inv.name}
+        </button>
+      </span>,
     );
   });
 
@@ -251,6 +265,9 @@ export function QuoteDetail({ store, q }: QuoteDetailProps) {
           ))}
         </div>
       )}
+      {preview.item && (
+        <FilePreviewModal url={preview.item.url} name={preview.item.name} onClose={preview.close} />
+      )}
     </div>
   );
 }