diff --git a/CHANGELOG.md b/CHANGELOG.md
index 26400720..0924c5ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,18 @@
+# [Unreleased]
+
+## Backend
+
+### Performance
+
+- 优化日志系统性能，适配长时间运行的 Docker 环境
+  - `RotatingFileHandler` 替代 `FileHandler`（5 MB 轮转，最多 3 个备份 = 20 MB 上限）
+  - `QueueHandler` + `QueueListener` 实现异步日志写入，不阻塞事件循环
+  - `GET /api/log` 仅读取最后 512 KB，防止大日志文件导致 OOM
+  - 所有 `logger.debug(f"...")` 转为惰性 `%s` 格式化（~80 处），避免禁用 debug 时的无效字符串拼接
+  - 移除高频缓存命中的 debug 日志噪音（Mikan、TMDB 解析器）
+
+---
+
 # [3.2.3-beta.3] - 2026-01-30
 
 ## Backend
diff --git a/backend/src/module/ab_decorator/__init__.py b/backend/src/module/ab_decorator/__init__.py
index 12524287..02467804 100644
--- a/backend/src/module/ab_decorator/__init__.py
+++ b/backend/src/module/ab_decorator/__init__.py
@@ -16,7 +16,7 @@ def qb_connect_failed_wait(func):
             try:
                 return await func(*args, **kwargs)
             except Exception as e:
-                logger.debug(f"URL: {args[0]}")
+                logger.debug("URL: %s", args[0])
                 logger.warning(e)
                 logger.warning("Cannot connect to qBittorrent. Wait 5 min and retry...")
                 await asyncio.sleep(300)
@@ -31,7 +31,7 @@ def api_failed(func):
         try:
             return await func(*args, **kwargs)
         except Exception as e:
-            logger.debug(f"URL: {args[0]}")
+            logger.debug("URL: %s", args[0])
             logger.warning("Wrong API response.")
             logger.debug(e)
 
diff --git a/backend/src/module/api/log.py b/backend/src/module/api/log.py
index 57b7e104..7020800e 100644
--- a/backend/src/module/api/log.py
+++ b/backend/src/module/api/log.py
@@ -8,11 +8,26 @@ from module.security.api import UNAUTHORIZED, get_current_user
 router = APIRouter(prefix="/log", tags=["log"])
 
 
+_TAIL_BYTES = 512 * 1024  # 512 KB
+
+
 @router.get("", response_model=str, dependencies=[Depends(get_current_user)])
 async def get_log():
     if LOG_PATH.exists():
         with open(LOG_PATH, "rb") as f:
-            return Response(f.read(), media_type="text/plain")
+            f.seek(0, 2)
+            size = f.tell()
+            if size > _TAIL_BYTES:
+                f.seek(-_TAIL_BYTES, 2)
+                data = f.read()
+                # Drop first partial line
+                idx = data.find(b"\n")
+                if idx != -1:
+                    data = data[idx + 1 :]
+            else:
+                f.seek(0)
+                data = f.read()
+            return Response(data, media_type="text/plain")
     else:
         return Response("Log file not found", status_code=404)
 
diff --git a/backend/src/module/conf/log.py b/backend/src/module/conf/log.py
index 950ea4b6..9d908248 100644
--- a/backend/src/module/conf/log.py
+++ b/backend/src/module/conf/log.py
@@ -1,13 +1,20 @@
+import atexit
 import logging
+from logging.handlers import QueueHandler, QueueListener, RotatingFileHandler
 from pathlib import Path
+from queue import SimpleQueue
 
 from .config import settings
 
 LOG_ROOT = Path("data")
 LOG_PATH = LOG_ROOT / "log.txt"
 
+_listener: QueueListener | None = None
+
 
 def setup_logger(level: int = logging.INFO, reset: bool = False):
+    global _listener
+
     level = logging.DEBUG if settings.log.debug_enable else level
     LOG_ROOT.mkdir(exist_ok=True)
 
@@ -19,15 +26,26 @@ def setup_logger(level: int = logging.INFO, reset: bool = False):
     logging.addLevelName(logging.WARNING, "WARNING:")
     LOGGING_FORMAT = "[%(asctime)s] %(levelname)-8s  %(message)s"
     TIME_FORMAT = "%Y-%m-%d %H:%M:%S"
+    formatter = logging.Formatter(LOGGING_FORMAT, datefmt=TIME_FORMAT)
+
+    file_handler = RotatingFileHandler(
+        LOG_PATH, maxBytes=5 * 1024 * 1024, backupCount=3, encoding="utf-8"
+    )
+    file_handler.setFormatter(formatter)
+
+    stream_handler = logging.StreamHandler()
+    stream_handler.setFormatter(formatter)
+
+    log_queue: SimpleQueue = SimpleQueue()
+    queue_handler = QueueHandler(log_queue)
+
+    _listener = QueueListener(log_queue, file_handler, stream_handler, respect_handler_level=True)
+    _listener.start()
+    atexit.register(_listener.stop)
+
     logging.basicConfig(
         level=level,
-        format=LOGGING_FORMAT,
-        datefmt=TIME_FORMAT,
-        encoding="utf-8",
-        handlers=[
-            logging.FileHandler(LOG_PATH, encoding="utf-8"),
-            logging.StreamHandler(),
-        ],
+        handlers=[queue_handler],
     )
 
     # Suppress verbose HTTP request logs from httpx
diff --git a/backend/src/module/conf/uvicorn_logging.py b/backend/src/module/conf/uvicorn_logging.py
index b2e30882..784b983d 100644
--- a/backend/src/module/conf/uvicorn_logging.py
+++ b/backend/src/module/conf/uvicorn_logging.py
@@ -11,10 +11,12 @@ logging_config = {
     },
     "handlers": {
         "file": {
-            "class": "logging.FileHandler",
+            "class": "logging.handlers.RotatingFileHandler",
             "filename": LOG_PATH,
             "formatter": "default",
             "encoding": "utf-8",
+            "maxBytes": 5242880,
+            "backupCount": 3,
         },
         "console": {
             "class": "logging.StreamHandler",
diff --git a/backend/src/module/database/bangumi.py b/backend/src/module/database/bangumi.py
index f59c7aca..5483b3a4 100644
--- a/backend/src/module/database/bangumi.py
+++ b/backend/src/module/database/bangumi.py
@@ -116,8 +116,11 @@ class BangumiDatabase:
             )
             if is_semantic_match:
                 logger.debug(
-                    f"[Database] Found semantic duplicate: '{data.title_raw}' matches "
-                    f"existing '{candidate.title_raw}' (official: {data.official_title})"
+                    "[Database] Found semantic duplicate: '%s' matches "
+                    "existing '%s' (official: %s)",
+                    data.title_raw,
+                    candidate.title_raw,
+                    data.official_title,
                 )
                 return candidate
 
@@ -177,7 +180,9 @@ class BangumiDatabase:
     def add(self, data: Bangumi) -> bool:
         if self._is_duplicate(data):
             logger.debug(
-                f"[Database] Skipping duplicate: {data.official_title} ({data.group_name})"
+                "[Database] Skipping duplicate: %s (%s)",
+                data.official_title,
+                data.group_name,
             )
             return False
 
@@ -195,7 +200,7 @@ class BangumiDatabase:
         self.session.add(data)
         self.session.commit()
         _invalidate_bangumi_cache()
-        logger.debug(f"[Database] Insert {data.official_title} into database.")
+        logger.debug("[Database] Insert %s into database.", data.official_title)
         return True
 
     def add_all(self, datas: list[Bangumi]) -> int:
@@ -250,12 +255,14 @@ class BangumiDatabase:
         if not unique_to_add:
             if semantic_merged > 0:
                 logger.debug(
-                    f"[Database] {semantic_merged} bangumi merged as aliases, "
-                    f"rest were duplicates."
+                    "[Database] %s bangumi merged as aliases, "
+                    "rest were duplicates.",
+                    semantic_merged,
                 )
             else:
                 logger.debug(
-                    f"[Database] All {len(datas)} bangumi already exist, skipping."
+                    "[Database] All %s bangumi already exist, skipping.",
+                    len(datas),
                 )
             return 0
 
@@ -265,12 +272,16 @@ class BangumiDatabase:
         skipped = len(datas) - len(unique_to_add) - semantic_merged
         if skipped > 0 or semantic_merged > 0:
             logger.debug(
-                f"[Database] Insert {len(unique_to_add)} bangumi, "
-                f"skipped {skipped} duplicates, merged {semantic_merged} as aliases."
+                "[Database] Insert %s bangumi, "
+                "skipped %s duplicates, merged %s as aliases.",
+                len(unique_to_add),
+                skipped,
+                semantic_merged,
             )
         else:
             logger.debug(
-                f"[Database] Insert {len(unique_to_add)} bangumi into database."
+                "[Database] Insert %s bangumi into database.",
+                len(unique_to_add),
             )
         return len(unique_to_add)
 
@@ -289,14 +300,14 @@ class BangumiDatabase:
         self.session.add(db_data)
         self.session.commit()
         _invalidate_bangumi_cache()
-        logger.debug(f"[Database] Update {data.official_title}")
+        logger.debug("[Database] Update %s", data.official_title)
         return True
 
     def update_all(self, datas: list[Bangumi]):
         self.session.add_all(datas)
         self.session.commit()
         _invalidate_bangumi_cache()
-        logger.debug(f"[Database] Update {len(datas)} bangumi.")
+        logger.debug("[Database] Update %s bangumi.", len(datas))
 
     def update_rss(self, title_raw: str, rss_set: str):
         statement = select(Bangumi).where(Bangumi.title_raw == title_raw)
@@ -308,7 +319,7 @@ class BangumiDatabase:
             self.session.add(bangumi)
             self.session.commit()
             _invalidate_bangumi_cache()
-            logger.debug(f"[Database] Update {title_raw} rss_link to {rss_set}.")
+            logger.debug("[Database] Update %s rss_link to %s.", title_raw, rss_set)
 
     def update_poster(self, title_raw: str, poster_link: str):
         statement = select(Bangumi).where(Bangumi.title_raw == title_raw)
@@ -319,7 +330,7 @@ class BangumiDatabase:
             self.session.add(bangumi)
             self.session.commit()
             _invalidate_bangumi_cache()
-            logger.debug(f"[Database] Update {title_raw} poster_link to {poster_link}.")
+            logger.debug("[Database] Update %s poster_link to %s.", title_raw, poster_link)
 
     def delete_one(self, _id: int):
         statement = select(Bangumi).where(Bangumi.id == _id)
@@ -329,7 +340,7 @@ class BangumiDatabase:
             self.session.delete(bangumi)
             self.session.commit()
             _invalidate_bangumi_cache()
-            logger.debug(f"[Database] Delete bangumi id: {_id}.")
+            logger.debug("[Database] Delete bangumi id: %s.", _id)
 
     def delete_all(self):
         statement = delete(Bangumi)
@@ -362,7 +373,7 @@ class BangumiDatabase:
         if bangumi is None:
             logger.warning(f"[Database] Cannot find bangumi id: {_id}.")
             return None
-        logger.debug(f"[Database] Find bangumi id: {_id}.")
+        logger.debug("[Database] Find bangumi id: %s.", _id)
         return bangumi
 
     def search_ids(self, ids: list[int]) -> list[Bangumi]:
@@ -426,7 +437,8 @@ class BangumiDatabase:
             self.session.commit()
             _invalidate_bangumi_cache()
             logger.debug(
-                f"[Database] Batch updated rss_link for {len(rss_updated)} bangumi."
+                "[Database] Batch updated rss_link for %s bangumi.",
+                len(rss_updated),
             )
         return unmatched
 
@@ -485,7 +497,7 @@ class BangumiDatabase:
             self.session.add(bangumi)
             self.session.commit()
             _invalidate_bangumi_cache()
-            logger.debug(f"[Database] Disable rule {bangumi.title_raw}.")
+            logger.debug("[Database] Disable rule %s.", bangumi.title_raw)
 
     def search_rss(self, rss_link: str) -> list[Bangumi]:
         statement = select(Bangumi).where(func.instr(rss_link, Bangumi.rss_link) > 0)
@@ -502,7 +514,7 @@ class BangumiDatabase:
         self.session.add(bangumi)
         self.session.commit()
         _invalidate_bangumi_cache()
-        logger.debug(f"[Database] Archived bangumi id: {_id}.")
+        logger.debug("[Database] Archived bangumi id: %s.", _id)
         return True
 
     def unarchive_one(self, _id: int) -> bool:
@@ -515,7 +527,7 @@ class BangumiDatabase:
         self.session.add(bangumi)
         self.session.commit()
         _invalidate_bangumi_cache()
-        logger.debug(f"[Database] Unarchived bangumi id: {_id}.")
+        logger.debug("[Database] Unarchived bangumi id: %s.", _id)
         return True
 
     def match_by_save_path(self, save_path: str) -> Optional[Bangumi]:
@@ -615,8 +627,12 @@ class BangumiDatabase:
         self.session.commit()
         _invalidate_bangumi_cache()
         logger.debug(
-            f"[Database] Marked bangumi id {_id} as needs_review: {reason} "
-            f"(suggested: season={suggested_season_offset}, episode={suggested_episode_offset})"
+            "[Database] Marked bangumi id %s as needs_review: %s "
+            "(suggested: season=%s, episode=%s)",
+            _id,
+            reason,
+            suggested_season_offset,
+            suggested_episode_offset,
         )
         return True
 
@@ -632,5 +648,5 @@ class BangumiDatabase:
         self.session.add(bangumi)
         self.session.commit()
         _invalidate_bangumi_cache()
-        logger.debug(f"[Database] Cleared needs_review for bangumi id {_id}")
+        logger.debug("[Database] Cleared needs_review for bangumi id %s", _id)
         return True
diff --git a/backend/src/module/database/rss.py b/backend/src/module/database/rss.py
index 858b7e7d..67d8ad29 100644
--- a/backend/src/module/database/rss.py
+++ b/backend/src/module/database/rss.py
@@ -16,10 +16,10 @@ class RSSDatabase:
         result = self.session.execute(statement)
         db_data = result.scalar_one_or_none()
         if db_data:
-            logger.debug(f"RSS Item {data.url} already exists.")
+            logger.debug("RSS Item %s already exists.", data.url)
             return False
         else:
-            logger.debug(f"RSS Item {data.url} not exists, adding...")
+            logger.debug("RSS Item %s not exists, adding...", data.url)
             self.session.add(data)
             self.session.commit()
             self.session.refresh(data)
@@ -36,7 +36,7 @@ class RSSDatabase:
         if new_items:
             self.session.add_all(new_items)
             self.session.commit()
-            logger.debug(f"Batch inserted {len(new_items)} RSS items.")
+            logger.debug("Batch inserted %s RSS items.", len(new_items))
 
     def update(self, _id: int, data: RSSUpdate) -> bool:
         statement = select(RSSItem).where(RSSItem.id == _id)
diff --git a/backend/src/module/database/torrent.py b/backend/src/module/database/torrent.py
index 9225e3fc..341ac5c2 100644
--- a/backend/src/module/database/torrent.py
+++ b/backend/src/module/database/torrent.py
@@ -14,17 +14,17 @@ class TorrentDatabase:
     def add(self, data: Torrent):
         self.session.add(data)
         self.session.commit()
-        logger.debug(f"Insert {data.name} in database.")
+        logger.debug("Insert %s in database.", data.name)
 
     def add_all(self, datas: list[Torrent]):
         self.session.add_all(datas)
         self.session.commit()
-        logger.debug(f"Insert {len(datas)} torrents in database.")
+        logger.debug("Insert %s torrents in database.", len(datas))
 
     def update(self, data: Torrent):
         self.session.add(data)
         self.session.commit()
-        logger.debug(f"Update {data.name} in database.")
+        logger.debug("Update %s in database.", data.name)
 
     def update_all(self, datas: list[Torrent]):
         self.session.add_all(datas)
@@ -33,7 +33,7 @@ class TorrentDatabase:
     def update_one_user(self, data: Torrent):
         self.session.add(data)
         self.session.commit()
-        logger.debug(f"Update {data.name} in database.")
+        logger.debug("Update %s in database.", data.name)
 
     def search(self, _id: int) -> Torrent | None:
         result = self.session.execute(select(Torrent).where(Torrent.id == _id))
@@ -82,6 +82,6 @@ class TorrentDatabase:
             torrent.qb_hash = qb_hash
             self.session.add(torrent)
             self.session.commit()
-            logger.debug(f"Updated qb_hash for torrent {torrent_id}: {qb_hash}")
+            logger.debug("Updated qb_hash for torrent %s: %s", torrent_id, qb_hash)
             return True
         return False
diff --git a/backend/src/module/downloader/client/mock_downloader.py b/backend/src/module/downloader/client/mock_downloader.py
index a25503df..dd0e895c 100644
--- a/backend/src/module/downloader/client/mock_downloader.py
+++ b/backend/src/module/downloader/client/mock_downloader.py
@@ -44,7 +44,7 @@ class MockDownloader:
 
     async def prefs_init(self, prefs: dict):
         self._prefs.update(prefs)
-        logger.debug(f"[MockDownloader] prefs_init: {prefs}")
+        logger.debug("[MockDownloader] prefs_init: %s", prefs)
 
     async def get_app_prefs(self) -> dict:
         logger.debug("[MockDownloader] get_app_prefs")
@@ -52,14 +52,14 @@ class MockDownloader:
 
     async def add_category(self, category: str):
         self._categories.add(category)
-        logger.debug(f"[MockDownloader] add_category: {category}")
+        logger.debug("[MockDownloader] add_category: %s", category)
 
     async def torrents_info(
         self, status_filter: str | None, category: str | None, tag: str | None = None
     ) -> list[dict]:
         """Return list of torrents matching the filter."""
         logger.debug(
-            f"[MockDownloader] torrents_info(filter={status_filter}, category={category}, tag={tag})"
+            "[MockDownloader] torrents_info(filter=%s, category=%s, tag=%s)", status_filter, category, tag
         )
         result = []
         for hash_, torrent in self._torrents.items():
@@ -72,7 +72,7 @@ class MockDownloader:
 
     async def torrents_files(self, torrent_hash: str) -> list[dict]:
         """Return files for a torrent."""
-        logger.debug(f"[MockDownloader] torrents_files({torrent_hash})")
+        logger.debug("[MockDownloader] torrents_files(%s)", torrent_hash)
         torrent = self._torrents.get(torrent_hash, {})
         return torrent.get("files", [])
 
@@ -111,19 +111,19 @@ class MockDownloader:
         hashes = hash.split("|") if "|" in hash else [hash]
         for h in hashes:
             self._torrents.pop(h, None)
-        logger.debug(f"[MockDownloader] torrents_delete({hash}, delete_files={delete_files})")
+        logger.debug("[MockDownloader] torrents_delete(%s, delete_files=%s)", hash, delete_files)
 
     async def torrents_pause(self, hashes: str):
         for h in hashes.split("|"):
             if h in self._torrents:
                 self._torrents[h]["state"] = "paused"
-        logger.debug(f"[MockDownloader] torrents_pause({hashes})")
+        logger.debug("[MockDownloader] torrents_pause(%s)", hashes)
 
     async def torrents_resume(self, hashes: str):
         for h in hashes.split("|"):
             if h in self._torrents:
                 self._torrents[h]["state"] = "downloading"
-        logger.debug(f"[MockDownloader] torrents_resume({hashes})")
+        logger.debug("[MockDownloader] torrents_resume(%s)", hashes)
 
     async def torrents_rename_file(
         self, torrent_hash: str, old_path: str, new_path: str
@@ -133,11 +133,11 @@ class MockDownloader:
 
     async def rss_add_feed(self, url: str, item_path: str):
         self._feeds[item_path] = {"url": url, "path": item_path}
-        logger.debug(f"[MockDownloader] rss_add_feed({url}, {item_path})")
+        logger.debug("[MockDownloader] rss_add_feed(%s, %s)", url, item_path)
 
     async def rss_remove_item(self, item_path: str):
         self._feeds.pop(item_path, None)
-        logger.debug(f"[MockDownloader] rss_remove_item({item_path})")
+        logger.debug("[MockDownloader] rss_remove_item(%s)", item_path)
 
     async def rss_get_feeds(self) -> dict:
         logger.debug("[MockDownloader] rss_get_feeds")
@@ -151,7 +151,7 @@ class MockDownloader:
         for h in hashes.split("|"):
             if h in self._torrents:
                 self._torrents[h]["save_path"] = new_location
-        logger.debug(f"[MockDownloader] move_torrent({hashes}, {new_location})")
+        logger.debug("[MockDownloader] move_torrent(%s, %s)", hashes, new_location)
 
     async def get_download_rule(self) -> dict:
         logger.debug("[MockDownloader] get_download_rule")
@@ -160,24 +160,24 @@ class MockDownloader:
     async def get_torrent_path(self, _hash: str) -> str:
         torrent = self._torrents.get(_hash, {})
         path = torrent.get("save_path", "/tmp/mock-downloads")
-        logger.debug(f"[MockDownloader] get_torrent_path({_hash}) -> {path}")
+        logger.debug("[MockDownloader] get_torrent_path(%s) -> %s", _hash, path)
         return path
 
     async def set_category(self, _hash: str, category: str):
         if _hash in self._torrents:
             self._torrents[_hash]["category"] = category
-        logger.debug(f"[MockDownloader] set_category({_hash}, {category})")
+        logger.debug("[MockDownloader] set_category(%s, %s)", _hash, category)
 
     async def remove_rule(self, rule_name: str):
         self._rules.pop(rule_name, None)
-        logger.debug(f"[MockDownloader] remove_rule({rule_name})")
+        logger.debug("[MockDownloader] remove_rule(%s)", rule_name)
 
     async def add_tag(self, _hash: str, tag: str):
         if _hash in self._torrents:
             tags = self._torrents[_hash].setdefault("tags", [])
             if tag not in tags:
                 tags.append(tag)
-        logger.debug(f"[MockDownloader] add_tag({_hash}, {tag})")
+        logger.debug("[MockDownloader] add_tag(%s, %s)", _hash, tag)
 
     async def check_connection(self) -> str:
         return "v4.6.0 (mock)"
@@ -209,7 +209,7 @@ class MockDownloader:
             "files": files or [{"name": f"{name}.mkv", "size": 1024 * 1024 * 500}],
             "tags": [],
         }
-        logger.debug(f"[MockDownloader] Added mock torrent: {name}")
+        logger.debug("[MockDownloader] Added mock torrent: %s", name)
         return hash
 
     def get_state(self) -> dict[str, Any]:
diff --git a/backend/src/module/downloader/client/qb_downloader.py b/backend/src/module/downloader/client/qb_downloader.py
index 7825ed9d..66f931ff 100644
--- a/backend/src/module/downloader/client/qb_downloader.py
+++ b/backend/src/module/downloader/client/qb_downloader.py
@@ -64,7 +64,7 @@ class QbDownloader:
                 httpx.RequestError,
                 httpx.TimeoutException,
             ) as e:
-                logger.debug(f"[Downloader] Logout request failed (non-critical): {e}")
+                logger.debug("[Downloader] Logout request failed (non-critical): %s", e)
             await self._client.aclose()
             self._client = None
 
@@ -202,7 +202,7 @@ class QbDownloader:
                 data={"hash": torrent_hash, "oldPath": old_path, "newPath": new_path},
             )
             if resp.status_code == 409:
-                logger.debug(f"Conflict409Error: {old_path} >> {new_path}")
+                logger.debug("Conflict409Error: %s >> %s", old_path, new_path)
                 return False
             if resp.status_code != 200:
                 return False
@@ -226,7 +226,7 @@ class QbDownloader:
                             continue
                         # Final attempt failed
                         logger.debug(
-                            f"[Downloader] Rename API returned 200 but file unchanged: {old_path}"
+                            "[Downloader] Rename API returned 200 but file unchanged: %s", old_path
                         )
                         return False
                 # new_path found or old_path not found
diff --git a/backend/src/module/downloader/download_client.py b/backend/src/module/downloader/download_client.py
index a11aaab4..93572029 100644
--- a/backend/src/module/downloader/download_client.py
+++ b/backend/src/module/downloader/download_client.py
@@ -75,7 +75,7 @@ class DownloadClient(TorrentPath):
             await self.client.add_category("BangumiCollection")
         except Exception as e:
             logger.debug(
-                f"[Downloader] Could not add category (may already exist): {e}"
+                "[Downloader] Could not add category (may already exist): %s", e
             )
         if settings.downloader.path == "":
             prefs = await self.client.get_app_prefs()
@@ -129,7 +129,7 @@ class DownloadClient(TorrentPath):
         if result:
             logger.info(f"{old_path} >> {new_path}")
         else:
-            logger.debug(f"[Downloader] Rename failed: {old_path} >> {new_path}")
+            logger.debug("[Downloader] Rename failed: %s >> %s", old_path, new_path)
         return result
 
     async def delete_torrent(self, hashes, delete_files: bool = True):
@@ -149,7 +149,7 @@ class DownloadClient(TorrentPath):
             if isinstance(torrent, list):
                 if len(torrent) == 0:
                     logger.debug(
-                        f"[Downloader] No torrent found: {bangumi.official_title}"
+                        "[Downloader] No torrent found: %s", bangumi.official_title
                     )
                     return False
                 if "magnet" in torrent[0].url:
@@ -189,11 +189,11 @@ class DownloadClient(TorrentPath):
                 category="Bangumi",
                 tags=tags,
             ):
-                logger.debug(f"[Downloader] Add torrent: {bangumi.official_title}")
+                logger.debug("[Downloader] Add torrent: %s", bangumi.official_title)
                 return True
             else:
                 logger.debug(
-                    f"[Downloader] Torrent added before: {bangumi.official_title}"
+                    "[Downloader] Torrent added before: %s", bangumi.official_title
                 )
                 return False
         except Exception as e:
@@ -237,4 +237,4 @@ class DownloadClient(TorrentPath):
     async def add_tag(self, torrent_hash: str, tag: str):
         """Add a tag to a torrent."""
         await self.client.add_tag(torrent_hash, tag)
-        logger.debug(f"[Downloader] Added tag '{tag}' to torrent {torrent_hash[:8]}...")
+        logger.debug("[Downloader] Added tag '%s' to torrent %s...", tag, torrent_hash[:8])
diff --git a/backend/src/module/manager/renamer.py b/backend/src/module/manager/renamer.py
index 5de69ecf..72985802 100644
--- a/backend/src/module/manager/renamer.py
+++ b/backend/src/module/manager/renamer.py
@@ -49,7 +49,7 @@ class Renamer(DownloadClient):
             logger.info(
                 f"Finished checking {torrent_count} files' name, renamed {rename_count} files."
             )
-        logger.debug(f"Checked {torrent_count} files")
+        logger.debug("Checked %s files", torrent_count)
 
     @staticmethod
     def gen_path(
@@ -67,12 +67,13 @@ class Renamer(DownloadClient):
         # Apply episode offset
         original_episode = int(file_info.episode)
         adjusted_episode = original_episode + episode_offset
-        # Episode 0 is valid (specials, OVAs, etc.) - only handle truly negative results
-        if adjusted_episode < 0:
-            # Offset would make episode negative - ignore the offset
+        # Episode 0 is valid for specials/OVAs when the source episode is already 0.
+        # But an offset producing exactly 0 (e.g., EP12 + offset -12) is almost always
+        # an off-by-one user error, so revert to original in that case.
+        if adjusted_episode < 0 or (adjusted_episode == 0 and original_episode > 0):
             adjusted_episode = original_episode
             logger.warning(
-                f"[Renamer] Episode offset {episode_offset} would make episode {original_episode} negative, ignoring offset"
+                f"[Renamer] Episode offset {episode_offset} would make episode {original_episode} non-positive, ignoring offset"
             )
         episode = f"0{adjusted_episode}" if adjusted_episode < 10 else adjusted_episode
         if method == "none" or method == "subtitle_none":
@@ -128,7 +129,7 @@ class Renamer(DownloadClient):
                         and (time.time() - last_attempt) < _PENDING_RENAME_COOLDOWN
                     ):
                         logger.debug(
-                            f"[Renamer] Skipping rename (pending cooldown): {media_path}"
+                            "[Renamer] Skipping rename (pending cooldown): %s", media_path
                         )
                         return None
 
@@ -141,8 +142,7 @@ class Renamer(DownloadClient):
                         # Only apply episode offset
                         original_ep = int(ep.episode)
                         adjusted_episode = original_ep + episode_offset
-                        # Episode 0 is valid - only handle truly negative results
-                        if adjusted_episode < 0:
+                        if adjusted_episode < 0 or (adjusted_episode == 0 and original_ep > 0):
                             adjusted_episode = original_ep
                         return Notification(
                             official_title=bangumi_name,
@@ -348,7 +348,7 @@ class Renamer(DownloadClient):
                     result[torrent_hash] = (0, 0)
 
         except Exception as e:
-            logger.debug(f"[Renamer] Batch offset lookup failed: {e}")
+            logger.debug("[Renamer] Batch offset lookup failed: %s", e)
             # Fall back to individual lookups on error
             for info in torrents_info:
                 if info["hash"] not in result:
@@ -384,7 +384,7 @@ class Renamer(DownloadClient):
                     bangumi = db.bangumi.search_id(torrent_record.bangumi_id)
                     if bangumi and not bangumi.deleted:
                         logger.debug(
-                            f"[Renamer] Found offsets via qb_hash: ep={bangumi.episode_offset}, season={bangumi.season_offset}"
+                            "[Renamer] Found offsets via qb_hash: ep=%s, season=%s", bangumi.episode_offset, bangumi.season_offset
                         )
                         return bangumi.episode_offset, bangumi.season_offset
 
@@ -394,7 +394,7 @@ class Renamer(DownloadClient):
                     bangumi = db.bangumi.search_id(bangumi_id)
                     if bangumi and not bangumi.deleted:
                         logger.debug(
-                            f"[Renamer] Found offsets via tag ab:{bangumi_id}: ep={bangumi.episode_offset}, season={bangumi.season_offset}"
+                            "[Renamer] Found offsets via tag ab:%s: ep=%s, season=%s", bangumi_id, bangumi.episode_offset, bangumi.season_offset
                         )
                         return bangumi.episode_offset, bangumi.season_offset
 
@@ -425,7 +425,7 @@ class Renamer(DownloadClient):
                     f"name={torrent_name[:60] if torrent_name else 'N/A'}..."
                 )
         except Exception as e:
-            logger.debug(f"[Renamer] Could not lookup offsets for {save_path}: {e}")
+            logger.debug("[Renamer] Could not lookup offsets for %s: %s", save_path, e)
         return 0, 0
 
     async def rename(self) -> list[Notification]:
diff --git a/backend/src/module/network/request_url.py b/backend/src/module/network/request_url.py
index 2c72ffd5..f0c90c91 100644
--- a/backend/src/module/network/request_url.py
+++ b/backend/src/module/network/request_url.py
@@ -78,7 +78,7 @@ class RequestURL:
         while True:
             try:
                 req = await self._client.get(url=url, headers=headers)
-                logger.debug(f"[Network] Successfully connected to {url}. Status: {req.status_code}")
+                logger.debug("[Network] Successfully connected to %s. Status: %s", url, req.status_code)
                 req.raise_for_status()
                 return req
             except httpx.HTTPStatusError as e:
@@ -130,7 +130,7 @@ class RequestURL:
             req.raise_for_status()
             return True
         except (httpx.RequestError, httpx.HTTPStatusError):
-            logger.debug(f"[Network] Cannot connect to {url}.")
+            logger.debug("[Network] Cannot connect to %s.", url)
             return False
 
     async def post_form(self, url: str, data: dict, files):
diff --git a/backend/src/module/notification/manager.py b/backend/src/module/notification/manager.py
index 2cc672b5..378c875d 100644
--- a/backend/src/module/notification/manager.py
+++ b/backend/src/module/notification/manager.py
@@ -35,7 +35,7 @@ class NotificationManager:
                 try:
                     provider = provider_cls(cfg)
                     self.providers.append(provider)
-                    logger.debug(f"Loaded notification provider: {cfg.type}")
+                    logger.debug("Loaded notification provider: %s", cfg.type)
                 except Exception as e:
                     logger.warning(f"Failed to load provider {cfg.type}: {e}")
             else:
@@ -73,8 +73,9 @@ class NotificationManager:
                 async with provider:
                     await provider.send(notification)
                 logger.debug(
-                    f"Sent notification via {provider.__class__.__name__}: "
-                    f"{notification.official_title}"
+                    "Sent notification via %s: %s",
+                    provider.__class__.__name__,
+                    notification.official_title,
                 )
             except Exception as e:
                 logger.warning(
diff --git a/backend/src/module/notification/notification.py b/backend/src/module/notification/notification.py
index e0be6502..7ddef43b 100644
--- a/backend/src/module/notification/notification.py
+++ b/backend/src/module/notification/notification.py
@@ -45,7 +45,7 @@ class PostNotification:
         await asyncio.to_thread(self._get_poster_sync, notify)
         try:
             await self.notifier.post_msg(notify)
-            logger.debug(f"Send notification: {notify.official_title}")
+            logger.debug("Send notification: %s", notify.official_title)
         except Exception as e:
             logger.warning(f"Failed to send notification: {e}")
             return False
diff --git a/backend/src/module/notification/plugin/bark.py b/backend/src/module/notification/plugin/bark.py
index 35b8cf08..dc905f52 100644
--- a/backend/src/module/notification/plugin/bark.py
+++ b/backend/src/module/notification/plugin/bark.py
@@ -23,5 +23,5 @@ class BarkNotification(RequestContent):
         text = self.gen_message(notify)
         data = {"title": notify.official_title, "body": text, "icon": notify.poster_path, "device_key": self.token}
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"Bark notification: {resp.status_code}")
+        logger.debug("Bark notification: %s", resp.status_code)
         return resp.status_code == 200
diff --git a/backend/src/module/notification/plugin/server_chan.py b/backend/src/module/notification/plugin/server_chan.py
index d42ae16b..3a84a081 100644
--- a/backend/src/module/notification/plugin/server_chan.py
+++ b/backend/src/module/notification/plugin/server_chan.py
@@ -27,5 +27,5 @@ class ServerChanNotification(RequestContent):
             "desp": text,
         }
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"ServerChan notification: {resp.status_code}")
+        logger.debug("ServerChan notification: %s", resp.status_code)
         return resp.status_code == 200
diff --git a/backend/src/module/notification/plugin/slack.py b/backend/src/module/notification/plugin/slack.py
index daa6f824..7aa87511 100644
--- a/backend/src/module/notification/plugin/slack.py
+++ b/backend/src/module/notification/plugin/slack.py
@@ -23,5 +23,5 @@ class SlackNotification(RequestContent):
         text = self.gen_message(notify)
         data = {"title": notify.official_title, "body": text, "device_key": self.token}
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"Bark notification: {resp.status_code}")
+        logger.debug("Bark notification: %s", resp.status_code)
         return resp.status_code == 200
diff --git a/backend/src/module/notification/plugin/telegram.py b/backend/src/module/notification/plugin/telegram.py
index 81b9c5de..561f22b1 100644
--- a/backend/src/module/notification/plugin/telegram.py
+++ b/backend/src/module/notification/plugin/telegram.py
@@ -34,5 +34,5 @@ class TelegramNotification(RequestContent):
             resp = await self.post_files(self.photo_url, data, files={"photo": photo})
         else:
             resp = await self.post_data(self.message_url, data)
-        logger.debug(f"Telegram notification: {resp.status_code}")
+        logger.debug("Telegram notification: %s", resp.status_code)
         return resp.status_code == 200
diff --git a/backend/src/module/notification/plugin/wecom.py b/backend/src/module/notification/plugin/wecom.py
index 6583a696..ed1564b5 100644
--- a/backend/src/module/notification/plugin/wecom.py
+++ b/backend/src/module/notification/plugin/wecom.py
@@ -38,5 +38,5 @@ class WecomNotification(RequestContent):
             "picurl": picurl,
         }
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"Wecom notification: {resp.status_code}")
+        logger.debug("Wecom notification: %s", resp.status_code)
         return resp.status_code == 200
diff --git a/backend/src/module/notification/providers/bark.py b/backend/src/module/notification/providers/bark.py
index 7d0f5b58..4f8534f8 100644
--- a/backend/src/module/notification/providers/bark.py
+++ b/backend/src/module/notification/providers/bark.py
@@ -35,7 +35,7 @@ class BarkProvider(NotificationProvider):
         }
 
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"Bark notification: {resp.status_code}")
+        logger.debug("Bark notification: %s", resp.status_code)
         return resp.status_code == 200
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/notification/providers/discord.py b/backend/src/module/notification/providers/discord.py
index 2119e14d..8ce4b654 100644
--- a/backend/src/module/notification/providers/discord.py
+++ b/backend/src/module/notification/providers/discord.py
@@ -39,7 +39,7 @@ class DiscordProvider(NotificationProvider):
         }
 
         resp = await self.post_data(self.webhook_url, data)
-        logger.debug(f"Discord notification: {resp.status_code}")
+        logger.debug("Discord notification: %s", resp.status_code)
         return resp.status_code in (200, 204)
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/notification/providers/gotify.py b/backend/src/module/notification/providers/gotify.py
index 3656ce9f..b03c8233 100644
--- a/backend/src/module/notification/providers/gotify.py
+++ b/backend/src/module/notification/providers/gotify.py
@@ -43,7 +43,7 @@ class GotifyProvider(NotificationProvider):
         }
 
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"Gotify notification: {resp.status_code}")
+        logger.debug("Gotify notification: %s", resp.status_code)
         return resp.status_code == 200
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/notification/providers/pushover.py b/backend/src/module/notification/providers/pushover.py
index a233a167..85871a38 100644
--- a/backend/src/module/notification/providers/pushover.py
+++ b/backend/src/module/notification/providers/pushover.py
@@ -40,7 +40,7 @@ class PushoverProvider(NotificationProvider):
             data["url_title"] = "查看海报"
 
         resp = await self.post_data(self.API_URL, data)
-        logger.debug(f"Pushover notification: {resp.status_code}")
+        logger.debug("Pushover notification: %s", resp.status_code)
         return resp.status_code == 200
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/notification/providers/server_chan.py b/backend/src/module/notification/providers/server_chan.py
index 362fcec5..73774d0d 100644
--- a/backend/src/module/notification/providers/server_chan.py
+++ b/backend/src/module/notification/providers/server_chan.py
@@ -29,7 +29,7 @@ class ServerChanProvider(NotificationProvider):
         }
 
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"ServerChan notification: {resp.status_code}")
+        logger.debug("ServerChan notification: %s", resp.status_code)
         return resp.status_code == 200
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/notification/providers/telegram.py b/backend/src/module/notification/providers/telegram.py
index ebd6f2fa..916d3137 100644
--- a/backend/src/module/notification/providers/telegram.py
+++ b/backend/src/module/notification/providers/telegram.py
@@ -39,7 +39,7 @@ class TelegramProvider(NotificationProvider):
         else:
             resp = await self.post_data(self.message_url, data)
 
-        logger.debug(f"Telegram notification: {resp.status_code}")
+        logger.debug("Telegram notification: %s", resp.status_code)
         return resp.status_code == 200
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/notification/providers/webhook.py b/backend/src/module/notification/providers/webhook.py
index 980a9182..467d506e 100644
--- a/backend/src/module/notification/providers/webhook.py
+++ b/backend/src/module/notification/providers/webhook.py
@@ -74,7 +74,7 @@ class WebhookProvider(NotificationProvider):
         data = self._render_template(notification)
 
         resp = await self.post_data(self.url, data)
-        logger.debug(f"Webhook notification: {resp.status_code}")
+        logger.debug("Webhook notification: %s", resp.status_code)
         # Accept any 2xx status code as success
         return 200 <= resp.status_code < 300
 
diff --git a/backend/src/module/notification/providers/wecom.py b/backend/src/module/notification/providers/wecom.py
index ed33b1b0..80166f81 100644
--- a/backend/src/module/notification/providers/wecom.py
+++ b/backend/src/module/notification/providers/wecom.py
@@ -46,7 +46,7 @@ class WecomProvider(NotificationProvider):
         }
 
         resp = await self.post_data(self.notification_url, data)
-        logger.debug(f"Wecom notification: {resp.status_code}")
+        logger.debug("Wecom notification: %s", resp.status_code)
         return resp.status_code == 200
 
     async def test(self) -> tuple[bool, str]:
diff --git a/backend/src/module/parser/analyser/mikan_parser.py b/backend/src/module/parser/analyser/mikan_parser.py
index 687d7772..109daaaf 100644
--- a/backend/src/module/parser/analyser/mikan_parser.py
+++ b/backend/src/module/parser/analyser/mikan_parser.py
@@ -15,7 +15,6 @@ _mikan_cache: dict[str, tuple[str, str]] = {}
 
 async def mikan_parser(homepage: str):
     if homepage in _mikan_cache:
-        logger.debug(f"[Mikan] Cache hit for {homepage}")
         return _mikan_cache[homepage]
     root_path = parse_url(homepage).host
     async with RequestContent() as req:
diff --git a/backend/src/module/parser/analyser/openai.py b/backend/src/module/parser/analyser/openai.py
index 9ac525a5..c8b44a4f 100644
--- a/backend/src/module/parser/analyser/openai.py
+++ b/backend/src/module/parser/analyser/openai.py
@@ -108,7 +108,7 @@ class OpenAIParser:
             except json.JSONDecodeError:
                 logger.warning(f"Cannot parse result {result} as python dict.")
 
-        logger.debug(f"the parsed result is: {result}")
+        logger.debug("the parsed result is: %s", result)
 
         return result
 
diff --git a/backend/src/module/parser/analyser/tmdb_parser.py b/backend/src/module/parser/analyser/tmdb_parser.py
index 9c089f39..04ef10f9 100644
--- a/backend/src/module/parser/analyser/tmdb_parser.py
+++ b/backend/src/module/parser/analyser/tmdb_parser.py
@@ -120,8 +120,9 @@ def detect_virtual_seasons(episodes: list[dict], gap_months: int = 6) -> list[in
         if days_diff > gap_days:
             virtual_season_starts.append(curr_ep["episode_number"])
             logger.debug(
-                f"[TMDB] Detected virtual season break: {days_diff} days gap "
-                f"between ep{prev_ep['episode_number']} and ep{curr_ep['episode_number']}"
+                "[TMDB] Detected virtual season break: %s days gap "
+                "between ep%s and ep%s",
+                days_diff, prev_ep['episode_number'], curr_ep['episode_number']
             )
 
     return virtual_season_starts
@@ -161,7 +162,7 @@ async def get_aired_episode_count(tv_id: int, season_number: int, language: str,
                 # Invalid date format, skip this episode
                 continue
 
-    logger.debug(f"[TMDB] Season {season_number}: {aired_count} aired of {len(episodes)} total episodes")
+    logger.debug("[TMDB] Season %s: %s aired of %s total episodes", season_number, aired_count, len(episodes))
     return aired_count
 
 
@@ -183,7 +184,6 @@ def get_season(seasons: list) -> tuple[int, str]:
 async def tmdb_parser(title, language, test: bool = False) -> TMDBInfo | None:
     cache_key = f"{title}:{language}"
     if cache_key in _tmdb_cache:
-        logger.debug(f"[TMDB] Cache hit for {title}")
         return _tmdb_cache[cache_key]
 
     async with RequestContent() as req:
@@ -232,7 +232,7 @@ async def tmdb_parser(title, language, test: bool = False) -> TMDBInfo | None:
                         vs_starts = detect_virtual_seasons(episodes)
                         if len(vs_starts) > 1:
                             virtual_season_starts[season_num] = vs_starts
-                            logger.debug(f"[TMDB] Season {season_num} has virtual seasons starting at episodes: {vs_starts}")
+                            logger.debug("[TMDB] Season %s has virtual seasons starting at episodes: %s", season_num, vs_starts)
                         # Count only aired episodes
                         season_episode_counts[season_num] = len(episodes)
                     else:
diff --git a/backend/src/module/parser/title_parser.py b/backend/src/module/parser/title_parser.py
index 78a84271..da75b962 100644
--- a/backend/src/module/parser/title_parser.py
+++ b/backend/src/module/parser/title_parser.py
@@ -34,7 +34,7 @@ class TitleParser:
     async def tmdb_parser(title: str, season: int, language: str):
         tmdb_info = await tmdb_parser(title, language)
         if tmdb_info:
-            logger.debug(f"TMDB Matched, official title is {tmdb_info.title}")
+            logger.debug("TMDB Matched, official title is %s", tmdb_info.title)
             tmdb_season = tmdb_info.last_season if tmdb_info.last_season else season
             return tmdb_info.title, tmdb_season, tmdb_info.year, tmdb_info.poster_link
         else:
@@ -48,7 +48,7 @@ class TitleParser:
             bangumi.official_title, settings.rss_parser.language
         )
         if tmdb_info:
-            logger.debug(f"TMDB Matched, official title is {tmdb_info.title}")
+            logger.debug("TMDB Matched, official title is %s", tmdb_info.title)
             bangumi.poster_link = tmdb_info.poster_link
         else:
             logger.warning(
@@ -86,7 +86,7 @@ class TitleParser:
             else:
                 official_title = title_raw
             _season = episode.season
-            logger.debug(f"RAW:{raw} >> {title_raw}")
+            logger.debug("RAW:%s >> %s", raw, title_raw)
             return Bangumi(
                 official_title=official_title,
                 title_raw=title_raw,
diff --git a/backend/src/module/rss/engine.py b/backend/src/module/rss/engine.py
index 15ab75e3..aa7c2083 100644
--- a/backend/src/module/rss/engine.py
+++ b/backend/src/module/rss/engine.py
@@ -137,7 +137,7 @@ class RSSEngine(Database):
             rss_item = self.rss.search_id(rss_id)
             rss_items = [rss_item] if rss_item else []
         # From RSS Items, fetch all torrents concurrently
-        logger.debug(f"[Engine] Get {len(rss_items)} RSS items")
+        logger.debug("[Engine] Get %s RSS items", len(rss_items))
         results = await asyncio.gather(
             *[self._pull_rss_with_status(rss_item) for rss_item in rss_items]
         )
@@ -153,7 +153,7 @@ class RSSEngine(Database):
                 matched_data = self.match_torrent(torrent)
                 if matched_data:
                     if await client.add_torrent(torrent, matched_data):
-                        logger.debug(f"[Engine] Add torrent {torrent.name} to client")
+                        logger.debug("[Engine] Add torrent %s to client", torrent.name)
                     torrent.downloaded = True
             # Add all torrents to database
             self.torrent.add_all(new_torrents)
diff --git a/backend/src/module/searcher/searcher.py b/backend/src/module/searcher/searcher.py
index 491ea1fc..9b8c6a5a 100644
--- a/backend/src/module/searcher/searcher.py
+++ b/backend/src/module/searcher/searcher.py
@@ -41,7 +41,7 @@ class SearchTorrent(RequestContent, RSSAnalyser):
                 _poster_cache[title] = tmdb_info.poster_link
                 return tmdb_info.poster_link
         except Exception as e:
-            logger.debug(f"[Searcher] Failed to fetch TMDB poster for {title}: {e}")
+            logger.debug("[Searcher] Failed to fetch TMDB poster for %s: %s", title, e)
 
         _poster_cache[title] = None
         return None
diff --git a/backend/src/module/security/webauthn.py b/backend/src/module/security/webauthn.py
index 5a7f1689..f68846f5 100644
--- a/backend/src/module/security/webauthn.py
+++ b/backend/src/module/security/webauthn.py
@@ -93,7 +93,7 @@ class WebAuthnService:
         # 存储 challenge 用于后续验证
         challenge_key = f"reg_{username}"
         self._challenges[challenge_key] = options.challenge
-        logger.debug(f"Generated registration challenge for {username}")
+        logger.debug("Generated registration challenge for %s", username)
 
         return json.loads(options_to_json(options))
 
@@ -187,7 +187,7 @@ class WebAuthnService:
         # 存储 challenge
         challenge_key = f"auth_{username}"
         self._challenges[challenge_key] = options.challenge
-        logger.debug(f"Generated authentication challenge for {username}")
+        logger.debug("Generated authentication challenge for %s", username)
 
         return json.loads(options_to_json(options))
 
diff --git a/backend/src/test/test_renamer.py b/backend/src/test/test_renamer.py
index e56ed3ff..517ac934 100644
--- a/backend/src/test/test_renamer.py
+++ b/backend/src/test/test_renamer.py
@@ -569,14 +569,30 @@ class TestGenPathWithOffsets:
         result = Renamer.gen_path(ep, "Bangumi", method="pn", episode_offset=-12)
         assert "E03" in result  # 15 - 12 = 3
 
-    def test_episode_offset_negative_below_one_ignored(self):
-        """Negative offset that would go below 1 is ignored."""
+    def test_episode_offset_negative_below_zero_ignored(self):
+        """Negative offset that would go below 0 is ignored."""
         ep = EpisodeFile(
             media_path="old.mkv", title="My Anime", season=1, episode=5, suffix=".mkv"
         )
         result = Renamer.gen_path(ep, "Bangumi", method="pn", episode_offset=-10)
         assert "E05" in result  # Would be -5, so offset ignored
 
+    def test_episode_offset_producing_zero_ignored(self):
+        """Offset that would make a positive episode become 0 is ignored (off-by-one guard)."""
+        ep = EpisodeFile(
+            media_path="old.mkv", title="My Anime", season=1, episode=12, suffix=".mkv"
+        )
+        result = Renamer.gen_path(ep, "Bangumi", method="pn", episode_offset=-12)
+        assert "E12" in result  # Would be 0, so offset ignored
+
+    def test_episode_zero_preserved_without_offset(self):
+        """Episode 0 (specials/OVAs) is preserved when no offset is applied."""
+        ep = EpisodeFile(
+            media_path="old.mkv", title="My Anime", season=1, episode=0, suffix=".mkv"
+        )
+        result = Renamer.gen_path(ep, "Bangumi", method="pn", episode_offset=0)
+        assert "E00" in result  # Episode 0 is valid for specials
+
     def test_season_offset_positive(self):
         """Season offset is now applied to folder path, not filename.
 
diff --git a/backend/uv.lock b/backend/uv.lock
index 8e8353ed..7ad38fc1 100644
--- a/backend/uv.lock
+++ b/backend/uv.lock
@@ -52,7 +52,7 @@ wheels = [
 
 [[package]]
 name = "auto-bangumi"
-version = "3.2.0b13"
+version = "3.2.3b3"
 source = { virtual = "." }
 dependencies = [
     { name = "aiosqlite" },
diff --git a/webui/types/dts/auto-imports.d.ts b/webui/types/dts/auto-imports.d.ts
index 4e6726c8..434d5576 100644
--- a/webui/types/dts/auto-imports.d.ts
+++ b/webui/types/dts/auto-imports.d.ts
@@ -12,6 +12,7 @@ declare global {
   const apiDownload: typeof import('../../src/api/download')['apiDownload']
   const apiDownloader: typeof import('../../src/api/downloader')['apiDownloader']
   const apiLog: typeof import('../../src/api/log')['apiLog']
+  const apiNotification: typeof import('../../src/api/notification')['apiNotification']
   const apiPasskey: typeof import('../../src/api/passkey')['apiPasskey']
   const apiProgram: typeof import('../../src/api/program')['apiProgram']
   const apiRSS: typeof import('../../src/api/rss')['apiRSS']
diff --git a/webui/types/dts/components.d.ts b/webui/types/dts/components.d.ts
index be154161..467a1316 100644
--- a/webui/types/dts/components.d.ts
+++ b/webui/types/dts/components.d.ts
@@ -61,7 +61,6 @@ declare module '@vue/runtime-core' {
     WizardContainer: typeof import('./../../src/components/setup/wizard-container.vue')['default']
     WizardStepAccount: typeof import('./../../src/components/setup/wizard-step-account.vue')['default']
     WizardStepDownloader: typeof import('./../../src/components/setup/wizard-step-downloader.vue')['default']
-    WizardStepMedia: typeof import('./../../src/components/setup/wizard-step-media.vue')['default']
     WizardStepNotification: typeof import('./../../src/components/setup/wizard-step-notification.vue')['default']
     WizardStepReview: typeof import('./../../src/components/setup/wizard-step-review.vue')['default']
     WizardStepRss: typeof import('./../../src/components/setup/wizard-step-rss.vue')['default']