diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..295a2ed
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,21 @@
+# Server Configuration
+HOST=127.0.0.1
+PORT=8002
+DEBUG=False
+
+# Security
+SECRET_KEY=change_this_to_a_random_secret_string
+SESSION_COOKIE_NAME=notes_session
+SESSION_EXPIRE_DAYS=30
+RATE_LIMIT_LOGIN_MAX=5
+RATE_LIMIT_LOGIN_WINDOW_SEC=60
+
+# Initial Admin Credentials (auto-provisioned on first run if no users exist)
+ADMIN_USERNAME=admin
+ADMIN_PASSWORD=change_this_admin_password
+
+# External APIs
+MYMEMORY_EMAIL=admin@qpid.pro
+
+# Database
+DB_PATH=/home/kopri/notes.qpid.pro/data/notes.db
diff --git a/app/__init__.py b/app/__init__.py
new file mode 100644
index 0000000..f21d8dc
--- /dev/null
+++ b/app/__init__.py
@@ -0,0 +1,2 @@
+"""Notes Application Package."""
+__version__ = "1.0.0"
diff --git a/app/auth.py b/app/auth.py
new file mode 100644
index 0000000..a254925
--- /dev/null
+++ b/app/auth.py
@@ -0,0 +1,116 @@
+import hashlib
+import os
+import secrets
+import time
+from datetime import datetime, timezone, timedelta
+from typing import Optional
+from app import config
+from app.database import get_db
+
+# In-memory IP-based rate limiting for login attempts
+_login_failures: dict[str, list[float]] = {}
+
+def hash_password(password: str, salt: Optional[str] = None) -> tuple[str, str]:
+    if not salt:
+        salt = secrets.token_hex(16)
+    salt_bytes = bytes.fromhex(salt)
+    key = hashlib.pbkdf2_hmac("sha256", password.encode("utf-8"), salt_bytes, 100_000)
+    return key.hex(), salt
+
+def verify_password(password: str, stored_hash: str, salt: str) -> bool:
+    new_hash, _ = hash_password(password, salt)
+    return secrets.compare_digest(new_hash, stored_hash)
+
+def check_login_rate_limit(ip: str) -> bool:
+    now = time.time()
+    cutoff = now - config.RATE_LIMIT_LOGIN_WINDOW_SEC
+    attempts = _login_failures.get(ip, [])
+    # Filter attempts within the time window
+    recent_attempts = [t for t in attempts if t > cutoff]
+    _login_failures[ip] = recent_attempts
+    return len(recent_attempts) < config.RATE_LIMIT_LOGIN_MAX
+
+def record_login_failure(ip: str):
+    now = time.time()
+    if ip not in _login_failures:
+        _login_failures[ip] = []
+    _login_failures[ip].append(now)
+
+def record_login_success(ip: str):
+    if ip in _login_failures:
+        _login_failures.pop(ip, None)
+
+def create_user(username: str, password: str) -> int:
+    pwd_hash, salt = hash_password(password)
+    with get_db() as conn:
+        cursor = conn.execute(
+            "INSERT INTO users (username, password_hash, salt) VALUES (?, ?, ?)",
+            (username.strip(), pwd_hash, salt)
+        )
+        return cursor.lastrowid
+
+def authenticate_user(username: str, password: str) -> Optional[dict]:
+    with get_db() as conn:
+        row = conn.execute(
+            "SELECT id, username, password_hash, salt FROM users WHERE username = ?",
+            (username.strip(),)
+        ).fetchone()
+        if not row:
+            return None
+        if verify_password(password, row["password_hash"], row["salt"]):
+            return {"id": row["id"], "username": row["username"]}
+        return None
+
+def create_session(user_id: int, user_agent: str = "", ip: str = "") -> str:
+    token = secrets.token_urlsafe(32)
+    expires_at = (datetime.now(timezone.utc) + timedelta(days=config.SESSION_EXPIRE_DAYS)).isoformat()
+    with get_db() as conn:
+        conn.execute(
+            "INSERT INTO sessions (token, user_id, expires_at, user_agent, ip) VALUES (?, ?, ?, ?, ?)",
+            (token, user_id, expires_at, user_agent, ip)
+        )
+    return token
+
+def get_user_from_session(token: str) -> Optional[dict]:
+    if not token:
+        return None
+    with get_db() as conn:
+        row = conn.execute(
+            """
+            SELECT u.id, u.username, s.expires_at
+            FROM sessions s
+            JOIN users u ON s.user_id = u.id
+            WHERE s.token = ?
+            """,
+            (token,)
+        ).fetchone()
+        if not row:
+            return None
+        
+        expires_at_str = row["expires_at"]
+        try:
+            expires_at = datetime.fromisoformat(expires_at_str)
+            if expires_at.tzinfo is None:
+                expires_at = expires_at.replace(tzinfo=timezone.utc)
+        except Exception:
+            return None
+
+        if expires_at < datetime.now(timezone.utc):
+            # Session expired
+            delete_session(token)
+            return None
+
+        return {"id": row["id"], "username": row["username"]}
+
+def delete_session(token: str):
+    if not token:
+        return
+    with get_db() as conn:
+        conn.execute("DELETE FROM sessions WHERE token = ?", (token,))
+
+def ensure_admin_user():
+    """Ensures at least one user exists; creates default admin from config if table empty."""
+    with get_db() as conn:
+        count = conn.execute("SELECT COUNT(*) FROM users").fetchone()[0]
+        if count == 0 and config.ADMIN_PASSWORD:
+            create_user(config.ADMIN_USERNAME, config.ADMIN_PASSWORD)
diff --git a/app/config.py b/app/config.py
new file mode 100644
index 0000000..8c053b6
--- /dev/null
+++ b/app/config.py
@@ -0,0 +1,40 @@
+import os
+from pathlib import Path
+
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+# Helper to read simple KEY=VALUE from .env without extra heavy dependencies
+def load_env_file(filepath: Path):
+    if not filepath.is_file():
+        return
+    with open(filepath, "r", encoding="utf-8") as f:
+        for line in f:
+            line = line.strip()
+            if not line or line.startswith("#") or "=" not in line:
+                continue
+            key, val = line.split("=", 1)
+            key = key.strip()
+            val = val.strip().strip("\"'")
+            if key not in os.environ:
+                os.environ[key] = val
+
+load_env_file(BASE_DIR / ".env")
+
+HOST = os.getenv("HOST", "127.0.0.1")
+PORT = int(os.getenv("PORT", "8002"))
+DEBUG = os.getenv("DEBUG", "False").lower() in ("1", "true", "yes")
+
+SECRET_KEY = os.getenv("SECRET_KEY", "default-dev-secret-key-please-change-in-production")
+SESSION_COOKIE_NAME = os.getenv("SESSION_COOKIE_NAME", "notes_session")
+SESSION_EXPIRE_DAYS = int(os.getenv("SESSION_EXPIRE_DAYS", "30"))
+
+RATE_LIMIT_LOGIN_MAX = int(os.getenv("RATE_LIMIT_LOGIN_MAX", "5"))
+RATE_LIMIT_LOGIN_WINDOW_SEC = int(os.getenv("RATE_LIMIT_LOGIN_WINDOW_SEC", "60"))
+
+ADMIN_USERNAME = os.getenv("ADMIN_USERNAME", "admin")
+ADMIN_PASSWORD = os.getenv("ADMIN_PASSWORD", "")
+
+MYMEMORY_EMAIL = os.getenv("MYMEMORY_EMAIL", "admin@qpid.pro")
+
+DB_PATH = Path(os.getenv("DB_PATH", str(BASE_DIR / "data" / "notes.db")))
+DB_PATH.parent.mkdir(parents=True, exist_ok=True)
diff --git a/app/database.py b/app/database.py
new file mode 100644
index 0000000..7cb550d
--- /dev/null
+++ b/app/database.py
@@ -0,0 +1,77 @@
+import sqlite3
+import contextlib
+from typing import Generator
+from app import config
+
+def get_db_connection() -> sqlite3.Connection:
+    conn = sqlite3.connect(
+        config.DB_PATH,
+        timeout=15.0
+    )
+    conn.row_factory = sqlite3.Row
+    conn.execute("PRAGMA journal_mode=WAL;")
+    conn.execute("PRAGMA synchronous=NORMAL;")
+    conn.execute("PRAGMA foreign_keys=ON;")
+    return conn
+
+@contextlib.contextmanager
+def get_db() -> Generator[sqlite3.Connection, None, None]:
+    conn = get_db_connection()
+    try:
+        yield conn
+        conn.commit()
+    except Exception:
+        conn.rollback()
+        raise
+    finally:
+        conn.close()
+
+def init_db():
+    config.DB_PATH.parent.mkdir(parents=True, exist_ok=True)
+    with get_db() as conn:
+        conn.executescript("""
+        CREATE TABLE IF NOT EXISTS users (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            username TEXT UNIQUE NOT NULL COLLATE NOCASE,
+            password_hash TEXT NOT NULL,
+            salt TEXT NOT NULL,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        );
+
+        CREATE TABLE IF NOT EXISTS sessions (
+            token TEXT PRIMARY KEY,
+            user_id INTEGER NOT NULL,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            expires_at TIMESTAMP NOT NULL,
+            user_agent TEXT,
+            ip TEXT,
+            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+        );
+
+        CREATE TABLE IF NOT EXISTS vocabulary_cards (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            user_id INTEGER NOT NULL,
+            term TEXT NOT NULL,
+            translation TEXT NOT NULL,
+            context_sentence TEXT,
+            phonetic TEXT,
+            audio_url TEXT,
+            part_of_speech TEXT,
+            definition_en TEXT,
+            tags TEXT,
+            notes TEXT,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+        );
+
+        CREATE INDEX IF NOT EXISTS idx_vocab_user ON vocabulary_cards(user_id);
+        CREATE INDEX IF NOT EXISTS idx_vocab_term ON vocabulary_cards(term);
+        CREATE INDEX IF NOT EXISTS idx_vocab_created ON vocabulary_cards(created_at DESC);
+
+        CREATE TABLE IF NOT EXISTS dictionary_cache (
+            query TEXT PRIMARY KEY COLLATE NOCASE,
+            response_json TEXT NOT NULL,
+            cached_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        );
+        """)
diff --git a/app/dictionary.py b/app/dictionary.py
new file mode 100644
index 0000000..324cb4b
--- /dev/null
+++ b/app/dictionary.py
@@ -0,0 +1,283 @@
+import json
+import re
+import urllib.parse
+from typing import Optional, Dict, Any, List
+import httpx
+from app import config
+from app.database import get_db
+
+USER_AGENT = "NotesApp/1.0 (https://notes.qpid.pro; admin@qpid.pro)"
+
+async def fetch_wiktionary_wikitext(word: str) -> Dict[str, Any]:
+    url = "https://en.wiktionary.org/w/api.php"
+    params = {
+        "action": "parse",
+        "page": word,
+        "prop": "wikitext",
+        "format": "json"
+    }
+    try:
+        async with httpx.AsyncClient(timeout=4.0) as client:
+            resp = await client.get(url, params=params, headers={"User-Agent": USER_AGENT})
+            if resp.status_code == 200:
+                data = resp.json()
+                wikitext = data.get("parse", {}).get("wikitext", {}).get("*", "")
+                
+                # Extract IPA
+                ipa_raw = re.findall(r"\{\{IPA\|en\|([^}]+)\}\}", wikitext)
+                ipa_cleaned = []
+                for entry in ipa_raw:
+                    parts = entry.split("|")
+                    for p in parts:
+                        if p.startswith("/"):
+                            ipa_cleaned.append(p)
+                
+                # Extract Audio file names
+                audio_matches = re.findall(r"\{\{audio\|en\|([^|}]+)", wikitext)
+                
+                # Extract Russian translations
+                ru_raw = re.findall(r"\{\{t[+-]?\|ru\|([^|}]+)", wikitext)
+                ru_cleaned = []
+                for r in ru_raw:
+                    # Clean wiki markup like [[word]] or stress marks
+                    clean = r.replace("[[", "").replace("]]", "").strip()
+                    if clean and clean not in ru_cleaned:
+                        ru_cleaned.append(clean)
+
+                return {
+                    "ipa": ipa_cleaned,
+                    "audio": audio_matches,
+                    "ru_translations": ru_cleaned
+                }
+    except Exception:
+        pass
+    return {"ipa": [], "audio": [], "ru_translations": []}
+
+async def fetch_wiktionary_definitions(word: str) -> Dict[str, Any]:
+    url = f"https://en.wiktionary.org/api/rest_v1/page/definition/{urllib.parse.quote(word)}"
+    try:
+        async with httpx.AsyncClient(timeout=4.0) as client:
+            resp = await client.get(url, headers={"User-Agent": USER_AGENT})
+            if resp.status_code == 200:
+                data = resp.json()
+                en_entries = data.get("en", [])
+                parts_of_speech = []
+                definitions = []
+                examples = []
+                for entry in en_entries:
+                    pos = entry.get("partOfSpeech")
+                    if pos and pos not in parts_of_speech:
+                        parts_of_speech.append(pos)
+                    for d in entry.get("definitions", []):
+                        raw_def = d.get("definition", "")
+                        # strip html tags
+                        clean_def = re.sub(r"<[^>]+>", "", raw_def).strip()
+                        if clean_def and clean_def not in definitions:
+                            definitions.append(clean_def)
+                        for ex in d.get("examples", []):
+                            clean_ex = re.sub(r"<[^>]+>", "", ex).strip()
+                            if clean_ex and clean_ex not in examples:
+                                examples.append(clean_ex)
+                return {
+                    "parts_of_speech": parts_of_speech,
+                    "definitions": definitions[:4],
+                    "examples": examples[:3]
+                }
+    except Exception:
+        pass
+    return {"parts_of_speech": [], "definitions": [], "examples": []}
+
+async def fetch_datamuse(word: str) -> Dict[str, Any]:
+    url = "https://api.datamuse.com/words"
+    params = {"sp": word, "md": "drp", "ipa": "1"}
+    try:
+        async with httpx.AsyncClient(timeout=3.0) as client:
+            resp = await client.get(url, params=params)
+            if resp.status_code == 200:
+                items = resp.json()
+                if items and isinstance(items, list):
+                    first = items[0]
+                    tags = first.get("tags", [])
+                    ipa = None
+                    pos = None
+                    for t in tags:
+                        if t.startswith("ipa_pron:"):
+                            ipa = "/" + t.split(":", 1)[1] + "/"
+                        elif t in ("n", "v", "adj", "adv"):
+                            pos_map = {"n": "Noun", "v": "Verb", "adj": "Adjective", "adv": "Adverb"}
+                            pos = pos_map.get(t)
+                    
+                    defs = []
+                    for d in first.get("defs", []):
+                        parts = d.split("\t", 1)
+                        defs.append(parts[1].strip() if len(parts) > 1 else parts[0].strip())
+
+                    return {
+                        "ipa": ipa,
+                        "part_of_speech": pos,
+                        "definitions": defs[:3]
+                    }
+    except Exception:
+        pass
+    return {"ipa": None, "part_of_speech": None, "definitions": []}
+
+async def fetch_mymemory(query: str) -> Dict[str, Any]:
+    url = "https://api.mymemory.translated.net/get"
+    params = {
+        "q": query,
+        "langpair": "en|ru",
+        "de": config.MYMEMORY_EMAIL
+    }
+    try:
+        async with httpx.AsyncClient(timeout=4.0) as client:
+            resp = await client.get(url, params=params)
+            if resp.status_code == 200:
+                data = resp.json()
+                main_trans = data.get("responseData", {}).get("translatedText", "").strip()
+                matches = data.get("matches", [])
+                alt_list = []
+                if main_trans:
+                    alt_list.append(main_trans)
+                for m in matches:
+                    t = m.get("translation", "").strip()
+                    if t and t not in alt_list and t.lower() != query.lower():
+                        alt_list.append(t)
+                return {
+                    "translation": main_trans,
+                    "matches": alt_list[:6]
+                }
+    except Exception:
+        pass
+    return {"translation": "", "matches": []}
+
+async def fetch_free_dictionary_api(word: str) -> Dict[str, Any]:
+    """Optional tier: api.dictionaryapi.dev with fast timeout."""
+    url = f"https://api.dictionaryapi.dev/api/v2/entries/en/{urllib.parse.quote(word)}"
+    try:
+        async with httpx.AsyncClient(timeout=1.5) as client:
+            resp = await client.get(url)
+            if resp.status_code == 200:
+                data = resp.json()[0]
+                phonetic = data.get("phonetic")
+                audio_url = None
+                for p in data.get("phonetics", []):
+                    if p.get("audio"):
+                        audio_url = p.get("audio")
+                        break
+                return {
+                    "phonetic": phonetic,
+                    "audio_url": audio_url
+                }
+    except Exception:
+        pass
+    return {"phonetic": None, "audio_url": None}
+
+async def lookup_term(query: str) -> Dict[str, Any]:
+    query_clean = query.strip()
+    if not query_clean:
+        return {}
+
+    # Check cache first
+    with get_db() as conn:
+        row = conn.execute(
+            "SELECT response_json FROM dictionary_cache WHERE query = ?",
+            (query_clean,)
+        ).fetchone()
+        if row:
+            try:
+                return json.loads(row["response_json"])
+            except Exception:
+                pass
+
+    words = query_clean.split()
+    is_sentence = len(words) > 4
+
+    result: Dict[str, Any] = {
+        "query": query_clean,
+        "is_sentence": is_sentence,
+        "translation": "",
+        "translations_list": [],
+        "phonetic": "",
+        "audio_file": "",
+        "audio_url": "",
+        "part_of_speech": "",
+        "definitions": [],
+        "examples": []
+    }
+
+    # Parallel queries via asyncio
+    import asyncio
+    
+    if is_sentence:
+        # For long sentences, primary focus is translation
+        mm_data = await fetch_mymemory(query_clean)
+        result["translation"] = mm_data.get("translation", "")
+        result["translations_list"] = mm_data.get("matches", [])
+    else:
+        # For words and short phrases
+        tasks = [
+            fetch_wiktionary_wikitext(query_clean),
+            fetch_wiktionary_definitions(query_clean),
+            fetch_datamuse(query_clean),
+            fetch_mymemory(query_clean),
+            fetch_free_dictionary_api(query_clean)
+        ]
+        w_wiki, w_defs, d_muse, mm_data, free_dict = await asyncio.gather(*tasks)
+
+        # 1. Phonetic IPA
+        if free_dict.get("phonetic"):
+            result["phonetic"] = free_dict["phonetic"]
+        elif w_wiki.get("ipa"):
+            result["phonetic"] = w_wiki["ipa"][0]
+        elif d_muse.get("ipa"):
+            result["phonetic"] = d_muse["ipa"]
+
+        # 2. Audio URL / File
+        if free_dict.get("audio_url"):
+            result["audio_url"] = free_dict["audio_url"]
+        elif w_wiki.get("audio"):
+            result["audio_file"] = w_wiki["audio"][0]
+            result["audio_url"] = f"/api/audio?file={urllib.parse.quote(result['audio_file'])}"
+
+        # 3. Part of Speech
+        if w_defs.get("parts_of_speech"):
+            result["part_of_speech"] = ", ".join(w_defs["parts_of_speech"][:2])
+        elif d_muse.get("part_of_speech"):
+            result["part_of_speech"] = d_muse["part_of_speech"]
+
+        # 4. Definitions & Examples
+        if w_defs.get("definitions"):
+            result["definitions"] = w_defs["definitions"]
+        elif d_muse.get("definitions"):
+            result["definitions"] = d_muse["definitions"]
+
+        if w_defs.get("examples"):
+            result["examples"] = w_defs["examples"]
+
+        # 5. Translations
+        candidates = []
+        # Wiktionary curated Russian translations
+        for t in w_wiki.get("ru_translations", []):
+            if t not in candidates:
+                candidates.append(t)
+
+        # MyMemory translation
+        for t in mm_data.get("matches", []):
+            if t and t not in candidates and t.lower() != query_clean.lower():
+                candidates.append(t)
+
+        if candidates:
+            result["translation"] = ", ".join(candidates[:3])
+            result["translations_list"] = candidates
+        else:
+            result["translation"] = mm_data.get("translation", "")
+            result["translations_list"] = [result["translation"]] if result["translation"] else []
+
+    # Store into SQLite cache
+    with get_db() as conn:
+        conn.execute(
+            "INSERT OR REPLACE INTO dictionary_cache (query, response_json) VALUES (?, ?)",
+            (query_clean, json.dumps(result, ensure_ascii=False))
+        )
+
+    return result
diff --git a/app/main.py b/app/main.py
new file mode 100644
index 0000000..74639b5
--- /dev/null
+++ b/app/main.py
@@ -0,0 +1,352 @@
+import os
+import urllib.parse
+from contextlib import asynccontextmanager
+from typing import Optional, List
+from fastapi import FastAPI, Depends, HTTPException, Request, Response, status, Query
+from fastapi.responses import HTMLResponse, StreamingResponse, JSONResponse
+from fastapi.staticfiles import StaticFiles
+from pydantic import BaseModel, Field
+import httpx
+
+from app import config
+from app.database import init_db, get_db
+from app.auth import (
+    ensure_admin_user,
+    authenticate_user,
+    create_session,
+    get_user_from_session,
+    delete_session,
+    check_login_rate_limit,
+    record_login_failure,
+    record_login_success
+)
+from app.dictionary import lookup_term, USER_AGENT
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    init_db()
+    ensure_admin_user()
+    yield
+
+app = FastAPI(
+    title="Notes App",
+    description="Personal Vocabulary & Language Notebook (notes.qpid.pro)",
+    version="1.0.0",
+    lifespan=lifespan
+)
+
+# Mount static files
+app.mount("/static", StaticFiles(directory=str(config.BASE_DIR / "app" / "static")), name="static")
+
+# Security Headers Middleware
+@app.middleware("http")
+async def add_security_headers(request: Request, call_next):
+    response = await call_next(request)
+    response.headers["X-Frame-Options"] = "SAMEORIGIN"
+    response.headers["X-Content-Type-Options"] = "nosniff"
+    response.headers["Referrer-Policy"] = "same-origin"
+    return response
+
+# Dependency: get authenticated user or None
+def get_optional_user(request: Request) -> Optional[dict]:
+    token = request.cookies.get(config.SESSION_COOKIE_NAME)
+    if not token:
+        # Check Authorization header bearer token fallback
+        auth_header = request.headers.get("Authorization", "")
+        if auth_header.startswith("Bearer "):
+            token = auth_header[7:].strip()
+    if token:
+        return get_user_from_session(token)
+    return None
+
+# Dependency: require authenticated user
+def require_user(request: Request) -> dict:
+    user = get_optional_user(request)
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Authentication required"
+        )
+    return user
+
+# Models
+class LoginRequest(BaseModel):
+    username: str = Field(..., min_length=1)
+    password: str = Field(..., min_length=1)
+
+class CardCreateRequest(BaseModel):
+    term: str = Field(..., min_length=1)
+    translation: str = Field(..., min_length=1)
+    context_sentence: Optional[str] = ""
+    phonetic: Optional[str] = ""
+    audio_url: Optional[str] = ""
+    part_of_speech: Optional[str] = ""
+    definition_en: Optional[str] = ""
+    tags: Optional[str] = "general"
+    notes: Optional[str] = ""
+
+class CardUpdateRequest(BaseModel):
+    term: Optional[str] = None
+    translation: Optional[str] = None
+    context_sentence: Optional[str] = None
+    phonetic: Optional[str] = None
+    audio_url: Optional[str] = None
+    part_of_speech: Optional[str] = None
+    definition_en: Optional[str] = None
+    tags: Optional[str] = None
+    notes: Optional[str] = None
+
+# Routes
+
+@app.api_route("/", methods=["GET", "HEAD"], response_class=HTMLResponse)
+async def serve_index(request: Request):
+    index_path = config.BASE_DIR / "app" / "static" / "index.html"
+    if not index_path.is_file():
+        raise HTTPException(status_code=404, detail="Index file not found")
+    with open(index_path, "r", encoding="utf-8") as f:
+        content = f.read()
+    return HTMLResponse(content)
+
+@app.post("/api/login")
+async def api_login(req: LoginRequest, request: Request, response: Response):
+    client_ip = request.client.host if request.client else "unknown"
+
+    if not check_login_rate_limit(client_ip):
+        raise HTTPException(
+            status_code=status.HTTP_429_TOO_MANY_REQUESTS,
+            detail="Too many failed login attempts. Please wait 1 minute."
+        )
+
+    user = authenticate_user(req.username, req.password)
+    if not user:
+        record_login_failure(client_ip)
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Invalid username or password"
+        )
+
+    record_login_success(client_ip)
+    user_agent = request.headers.get("User-Agent", "")[:255]
+    session_token = create_session(user["id"], user_agent, client_ip)
+
+    # Set secure HttpOnly cookie
+    response.set_cookie(
+        key=config.SESSION_COOKIE_NAME,
+        value=session_token,
+        max_age=config.SESSION_EXPIRE_DAYS * 86400,
+        httponly=True,
+        samesite="lax",
+        secure=False  # Nginx handles SSL termination
+    )
+
+    return {"status": "ok", "user": user}
+
+@app.post("/api/logout")
+async def api_logout(request: Request, response: Response):
+    token = request.cookies.get(config.SESSION_COOKIE_NAME)
+    if token:
+        delete_session(token)
+    response.delete_cookie(config.SESSION_COOKIE_NAME)
+    return {"status": "ok", "message": "Logged out successfully"}
+
+@app.get("/api/me")
+async def api_me(user: dict = Depends(require_user)):
+    return {"user": user}
+
+@app.get("/api/lookup")
+async def api_lookup(q: str = Query(..., min_length=1), user: dict = Depends(require_user)):
+    result = await lookup_term(q)
+    return result
+
+@app.get("/api/audio")
+async def api_audio_proxy(file: str = Query(..., min_length=1)):
+    """Proxies Wikimedia audio file with required User-Agent."""
+    cleaned_file = urllib.parse.unquote(file).strip()
+    # Basic safety check
+    if ".." in cleaned_file or "/" in cleaned_file or "\\" in cleaned_file:
+        raise HTTPException(status_code=400, detail="Invalid filename")
+
+    target_url = f"https://commons.wikimedia.org/wiki/Special:FilePath/{urllib.parse.quote(cleaned_file)}"
+
+    async def stream_audio():
+        headers = {"User-Agent": USER_AGENT}
+        async with httpx.AsyncClient(follow_redirects=True, timeout=10.0) as client:
+            async with client.stream("GET", target_url, headers=headers) as resp:
+                if resp.status_code != 200:
+                    yield b""
+                    return
+                async for chunk in resp.aiter_bytes():
+                    yield chunk
+
+    # Determine mime-type based on extension
+    ext = cleaned_file.lower().split(".")[-1]
+    mime_map = {
+        "ogg": "audio/ogg",
+        "oga": "audio/ogg",
+        "mp3": "audio/mpeg",
+        "wav": "audio/wav",
+        "flac": "audio/flac"
+    }
+    media_type = mime_map.get(ext, "application/octet-stream")
+
+    return StreamingResponse(
+        stream_audio(),
+        media_type=media_type,
+        headers={"Cache-Control": "public, max-age=86400"}
+    )
+
+@app.get("/api/cards")
+async def api_get_cards(
+    search: Optional[str] = None,
+    tag: Optional[str] = None,
+    limit: int = 100,
+    offset: int = 0,
+    user: dict = Depends(require_user)
+):
+    with get_db() as conn:
+        query = """
+            SELECT id, term, translation, context_sentence, phonetic, audio_url,
+                   part_of_speech, definition_en, tags, notes, created_at, updated_at
+            FROM vocabulary_cards
+            WHERE user_id = ?
+        """
+        params = [user["id"]]
+
+        if search:
+            query += " AND (term LIKE ? OR translation LIKE ? OR context_sentence LIKE ? OR notes LIKE ?)"
+            s = f"%{search.strip()}%"
+            params.extend([s, s, s, s])
+
+        if tag:
+            query += " AND (',' || tags || ',') LIKE ?"
+            params.append(f"%,{tag.strip()}%,")
+
+        query += " ORDER BY created_at DESC LIMIT ? OFFSET ?"
+        params.extend([min(limit, 500), max(offset, 0)])
+
+        rows = conn.execute(query, params).fetchall()
+
+        # Count total
+        count_query = "SELECT COUNT(*) FROM vocabulary_cards WHERE user_id = ?"
+        count_params = [user["id"]]
+        if search:
+            count_query += " AND (term LIKE ? OR translation LIKE ? OR context_sentence LIKE ? OR notes LIKE ?)"
+            s = f"%{search.strip()}%"
+            count_params.extend([s, s, s, s])
+        if tag:
+            count_query += " AND (',' || tags || ',') LIKE ?"
+            count_params.append(f"%,{tag.strip()}%,")
+        total = conn.execute(count_query, count_params).fetchone()[0]
+
+        cards = [dict(r) for r in rows]
+        return {"total": total, "cards": cards}
+
+@app.post("/api/cards")
+async def api_create_card(card: CardCreateRequest, user: dict = Depends(require_user)):
+    with get_db() as conn:
+        cursor = conn.execute(
+            """
+            INSERT INTO vocabulary_cards (
+                user_id, term, translation, context_sentence, phonetic, audio_url,
+                part_of_speech, definition_en, tags, notes
+            ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+            """,
+            (
+                user["id"],
+                card.term.strip(),
+                card.translation.strip(),
+                card.context_sentence.strip() if card.context_sentence else "",
+                card.phonetic.strip() if card.phonetic else "",
+                card.audio_url.strip() if card.audio_url else "",
+                card.part_of_speech.strip() if card.part_of_speech else "",
+                card.definition_en.strip() if card.definition_en else "",
+                card.tags.strip() if card.tags else "general",
+                card.notes.strip() if card.notes else ""
+            )
+        )
+        new_id = cursor.lastrowid
+        row = conn.execute("SELECT * FROM vocabulary_cards WHERE id = ?", (new_id,)).fetchone()
+        return dict(row)
+
+@app.put("/api/cards/{card_id}")
+async def api_update_card(card_id: int, update: CardUpdateRequest, user: dict = Depends(require_user)):
+    with get_db() as conn:
+        row = conn.execute("SELECT * FROM vocabulary_cards WHERE id = ? AND user_id = ?", (card_id, user["id"])).fetchone()
+        if not row:
+            raise HTTPException(status_code=404, detail="Card not found")
+
+        current = dict(row)
+        term = update.term.strip() if update.term is not None else current["term"]
+        translation = update.translation.strip() if update.translation is not None else current["translation"]
+        context_sentence = update.context_sentence.strip() if update.context_sentence is not None else current["context_sentence"]
+        phonetic = update.phonetic.strip() if update.phonetic is not None else current["phonetic"]
+        audio_url = update.audio_url.strip() if update.audio_url is not None else current["audio_url"]
+        part_of_speech = update.part_of_speech.strip() if update.part_of_speech is not None else current["part_of_speech"]
+        definition_en = update.definition_en.strip() if update.definition_en is not None else current["definition_en"]
+        tags = update.tags.strip() if update.tags is not None else current["tags"]
+        notes = update.notes.strip() if update.notes is not None else current["notes"]
+
+        conn.execute(
+            """
+            UPDATE vocabulary_cards
+            SET term = ?, translation = ?, context_sentence = ?, phonetic = ?,
+                audio_url = ?, part_of_speech = ?, definition_en = ?, tags = ?,
+                notes = ?, updated_at = CURRENT_TIMESTAMP
+            WHERE id = ? AND user_id = ?
+            """,
+            (term, translation, context_sentence, phonetic, audio_url, part_of_speech, definition_en, tags, notes, card_id, user["id"])
+        )
+        updated_row = conn.execute("SELECT * FROM vocabulary_cards WHERE id = ?", (card_id,)).fetchone()
+        return dict(updated_row)
+
+@app.delete("/api/cards/{card_id}")
+async def api_delete_card(card_id: int, user: dict = Depends(require_user)):
+    with get_db() as conn:
+        cursor = conn.execute(
+            "DELETE FROM vocabulary_cards WHERE id = ? AND user_id = ?",
+            (card_id, user["id"])
+        )
+        if cursor.rowcount == 0:
+            raise HTTPException(status_code=404, detail="Card not found")
+        return {"status": "ok", "deleted_id": card_id}
+
+@app.get("/api/tags")
+async def api_get_tags(user: dict = Depends(require_user)):
+    with get_db() as conn:
+        rows = conn.execute(
+            "SELECT tags FROM vocabulary_cards WHERE user_id = ?",
+            (user["id"],)
+        ).fetchall()
+        tag_counts: dict[str, int] = {}
+        for r in rows:
+            raw = r["tags"]
+            if raw:
+                for t in raw.split(","):
+                    tag_clean = t.strip()
+                    if tag_clean:
+                        tag_counts[tag_clean] = tag_counts.get(tag_clean, 0) + 1
+        sorted_tags = sorted(
+            [{"tag": k, "count": v} for k, v in tag_counts.items()],
+            key=lambda x: x["count"],
+            reverse=True
+        )
+        return sorted_tags
+
+@app.get("/api/stats")
+async def api_stats(user: dict = Depends(require_user)):
+    with get_db() as conn:
+        total = conn.execute(
+            "SELECT COUNT(*) FROM vocabulary_cards WHERE user_id = ?",
+            (user["id"],)
+        ).fetchone()[0]
+        today_added = conn.execute(
+            """
+            SELECT COUNT(*) FROM vocabulary_cards
+            WHERE user_id = ? AND date(created_at) = date('now')
+            """,
+            (user["id"],)
+        ).fetchone()[0]
+        return {
+            "total_cards": total,
+            "today_added": today_added
+        }
diff --git a/app/static/css/style.css b/app/static/css/style.css
new file mode 100644
index 0000000..fb647f9
--- /dev/null
+++ b/app/static/css/style.css
@@ -0,0 +1,951 @@
+/* Modern CSS Design System for Notes App */
+:root {
+    --bg-main: #0f172a;
+    --bg-surface: #1e293b;
+    --bg-surface-hover: #334155;
+    --bg-card: #1e293b;
+    --bg-input: #0f172a;
+    --border-color: #334155;
+    --border-focus: #38bdf8;
+    
+    --text-main: #f8fafc;
+    --text-muted: #94a3b8;
+    --text-dim: #64748b;
+    
+    --primary: #38bdf8;
+    --primary-hover: #0ea5e9;
+    --primary-dim: rgba(56, 189, 248, 0.15);
+    
+    --success: #10b981;
+    --success-hover: #059669;
+    --success-dim: rgba(16, 185, 129, 0.15);
+    
+    --danger: #ef4444;
+    --danger-hover: #dc2626;
+    --danger-dim: rgba(239, 68, 68, 0.15);
+    
+    --tag-bg: #293548;
+    --tag-text: #7dd3fc;
+    
+    --radius-sm: 6px;
+    --radius-md: 10px;
+    --radius-lg: 14px;
+    --radius-full: 9999px;
+    
+    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
+    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
+    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
+    
+    --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
+    --transition: all 0.18s ease-in-out;
+}
+
+[data-theme="light"] {
+    --bg-main: #f1f5f9;
+    --bg-surface: #ffffff;
+    --bg-surface-hover: #f8fafc;
+    --bg-card: #ffffff;
+    --bg-input: #f8fafc;
+    --border-color: #cbd5e1;
+    --border-focus: #0284c7;
+    
+    --text-main: #0f172a;
+    --text-muted: #475569;
+    --text-dim: #94a3b8;
+    
+    --primary: #0284c7;
+    --primary-hover: #0369a1;
+    --primary-dim: rgba(2, 132, 199, 0.1);
+    
+    --success: #059669;
+    --success-hover: #047857;
+    --success-dim: rgba(5, 150, 105, 0.1);
+    
+    --tag-bg: #e2e8f0;
+    --tag-text: #0369a1;
+    
+    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
+    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08);
+    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
+}
+
+* {
+    box-sizing: border-box;
+    margin: 0;
+    padding: 0;
+}
+
+body {
+    background-color: var(--bg-main);
+    color: var(--text-main);
+    font-family: var(--font-family);
+    line-height: 1.5;
+    -webkit-font-smoothing: antialiased;
+    min-height: 100vh;
+}
+
+.hidden {
+    display: none !important;
+}
+
+/* Auth Screen */
+.auth-screen {
+    min-height: 100vh;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 20px;
+    background: radial-gradient(circle at top, rgba(56, 189, 248, 0.12), transparent 70%);
+}
+
+.auth-card {
+    background-color: var(--bg-surface);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-lg);
+    padding: 36px 32px;
+    width: 100%;
+    max-width: 420px;
+    box-shadow: var(--shadow-lg);
+}
+
+.auth-header {
+    text-align: center;
+    margin-bottom: 28px;
+}
+
+.auth-header .app-logo {
+    font-size: 48px;
+    margin-bottom: 8px;
+}
+
+.auth-header h2 {
+    font-size: 24px;
+    font-weight: 700;
+    color: var(--text-main);
+}
+
+.auth-header p {
+    color: var(--text-muted);
+    font-size: 14px;
+    margin-top: 4px;
+}
+
+.auth-footer {
+    margin-top: 24px;
+    text-align: center;
+    font-size: 12px;
+    color: var(--text-dim);
+}
+
+.form-group {
+    margin-bottom: 18px;
+}
+
+.form-group label {
+    display: block;
+    font-size: 13px;
+    font-weight: 600;
+    color: var(--text-muted);
+    margin-bottom: 6px;
+}
+
+.form-group input {
+    width: 100%;
+    padding: 12px 14px;
+    background-color: var(--bg-input);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-sm);
+    color: var(--text-main);
+    font-size: 15px;
+    outline: none;
+    transition: var(--transition);
+}
+
+.form-group input:focus {
+    border-color: var(--border-focus);
+    box-shadow: 0 0 0 3px var(--primary-dim);
+}
+
+.error-banner {
+    background-color: var(--danger-dim);
+    border: 1px solid var(--danger);
+    color: #fca5a5;
+    padding: 10px 14px;
+    border-radius: var(--radius-sm);
+    font-size: 13px;
+    margin-bottom: 16px;
+}
+
+/* App Navbar */
+.app-container {
+    display: flex;
+    flex-direction: column;
+    min-height: 100vh;
+}
+
+.navbar {
+    background-color: var(--bg-surface);
+    border-bottom: 1px solid var(--border-color);
+    padding: 12px 24px;
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    position: sticky;
+    top: 0;
+    z-index: 100;
+}
+
+.nav-brand {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+}
+
+.brand-icon {
+    font-size: 24px;
+}
+
+.brand-title {
+    font-size: 20px;
+    font-weight: 800;
+    color: var(--text-main);
+    letter-spacing: -0.5px;
+}
+
+.brand-sub {
+    font-size: 12px;
+    background-color: var(--primary-dim);
+    color: var(--primary);
+    padding: 2px 8px;
+    border-radius: var(--radius-full);
+    font-weight: 600;
+    margin-left: 4px;
+}
+
+.nav-stats {
+    display: flex;
+    gap: 12px;
+}
+
+.stat-badge {
+    font-size: 13px;
+    background-color: var(--bg-main);
+    border: 1px solid var(--border-color);
+    padding: 4px 12px;
+    border-radius: var(--radius-full);
+    color: var(--text-muted);
+}
+
+.stat-badge strong {
+    color: var(--text-main);
+}
+
+.stat-badge.stat-today strong {
+    color: var(--success);
+}
+
+.nav-actions {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+}
+
+.user-profile {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+}
+
+.user-badge {
+    font-size: 13px;
+    color: var(--text-muted);
+    font-weight: 600;
+    background-color: var(--bg-surface-hover);
+    padding: 4px 10px;
+    border-radius: var(--radius-sm);
+}
+
+/* Buttons */
+.btn {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    gap: 6px;
+    padding: 10px 18px;
+    border-radius: var(--radius-sm);
+    font-size: 14px;
+    font-weight: 600;
+    cursor: pointer;
+    border: none;
+    transition: var(--transition);
+}
+
+.btn-primary {
+    background-color: var(--primary);
+    color: #0f172a;
+}
+
+.btn-primary:hover {
+    background-color: var(--primary-hover);
+}
+
+.btn-success {
+    background-color: var(--success);
+    color: #ffffff;
+}
+
+.btn-success:hover {
+    background-color: var(--success-hover);
+}
+
+.btn-outline {
+    background-color: transparent;
+    border: 1px solid var(--border-color);
+    color: var(--text-muted);
+}
+
+.btn-outline:hover {
+    border-color: var(--text-main);
+    color: var(--text-main);
+}
+
+.btn-sm {
+    padding: 6px 12px;
+    font-size: 12px;
+}
+
+.btn-lg {
+    padding: 14px 24px;
+    font-size: 16px;
+}
+
+.btn-block {
+    width: 100%;
+}
+
+.btn-subtext {
+    font-size: 11px;
+    opacity: 0.8;
+    margin-left: 4px;
+}
+
+.icon-btn {
+    background: transparent;
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-sm);
+    padding: 6px 10px;
+    cursor: pointer;
+    color: var(--text-muted);
+    font-size: 16px;
+    transition: var(--transition);
+}
+
+.icon-btn:hover {
+    color: var(--text-main);
+    border-color: var(--text-main);
+}
+
+/* Main Content */
+.main-content {
+    max-width: 900px;
+    width: 100%;
+    margin: 0 auto;
+    padding: 32px 20px;
+    display: flex;
+    flex-direction: column;
+    gap: 36px;
+}
+
+/* Search Box */
+.search-box-wrapper {
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+}
+
+.search-input-box {
+    display: flex;
+    align-items: center;
+    background-color: var(--bg-surface);
+    border: 2px solid var(--border-color);
+    border-radius: var(--radius-md);
+    padding: 6px 10px 6px 16px;
+    transition: var(--transition);
+    box-shadow: var(--shadow-sm);
+}
+
+.search-input-box:focus-within {
+    border-color: var(--border-focus);
+    box-shadow: 0 0 0 4px var(--primary-dim);
+}
+
+.search-icon {
+    font-size: 18px;
+    color: var(--text-muted);
+    margin-right: 12px;
+}
+
+.search-input-box input {
+    flex: 1;
+    background: transparent;
+    border: none;
+    outline: none;
+    font-size: 17px;
+    color: var(--text-main);
+    padding: 8px 0;
+}
+
+.clear-btn {
+    background: transparent;
+    border: none;
+    color: var(--text-dim);
+    font-size: 16px;
+    cursor: pointer;
+    padding: 4px 8px;
+    border-radius: 50%;
+}
+
+.clear-btn:hover {
+    color: var(--text-main);
+}
+
+.translate-action-btn {
+    margin-left: 8px;
+}
+
+.hotkey-hints {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 12px;
+    padding: 4px 8px;
+    font-size: 12px;
+    color: var(--text-dim);
+}
+
+.hotkey-hints kbd {
+    background-color: var(--bg-surface-hover);
+    border: 1px solid var(--border-color);
+    border-radius: 4px;
+    padding: 1px 5px;
+    font-family: monospace;
+    font-size: 11px;
+    color: var(--text-muted);
+}
+
+/* Spinner */
+.lookup-spinner {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: 12px;
+    padding: 24px;
+    color: var(--primary);
+    font-size: 14px;
+    font-weight: 500;
+}
+
+.spinner {
+    width: 24px;
+    height: 24px;
+    border: 3px solid var(--border-color);
+    border-top-color: var(--primary);
+    border-radius: 50%;
+    animation: spin 0.8s linear infinite;
+}
+
+@keyframes spin {
+    to { transform: rotate(360deg); }
+}
+
+/* Live Result Card */
+.result-card {
+    background-color: var(--bg-card);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-lg);
+    padding: 24px;
+    box-shadow: var(--shadow-md);
+    animation: fadeIn 0.25s ease-out;
+}
+
+@keyframes fadeIn {
+    from { opacity: 0; transform: translateY(6px); }
+    to { opacity: 1; transform: translateY(0); }
+}
+
+.result-header {
+    margin-bottom: 16px;
+    padding-bottom: 16px;
+    border-bottom: 1px solid var(--border-color);
+}
+
+.term-title-row {
+    display: flex;
+    align-items: center;
+    flex-wrap: wrap;
+    gap: 12px;
+}
+
+.res-term {
+    font-size: 28px;
+    font-weight: 800;
+    letter-spacing: -0.5px;
+    color: var(--text-main);
+}
+
+.badge-pill {
+    padding: 3px 10px;
+    border-radius: var(--radius-full);
+    font-size: 13px;
+    font-weight: 600;
+}
+
+.res-phonetic {
+    background-color: var(--primary-dim);
+    color: var(--primary);
+    font-family: monospace;
+}
+
+.res-pos {
+    background-color: var(--bg-surface-hover);
+    color: var(--text-muted);
+}
+
+.audio-btn {
+    background-color: var(--primary-dim);
+    border: 1px solid var(--primary);
+    color: var(--primary);
+    border-radius: var(--radius-full);
+    padding: 4px 12px;
+    font-size: 13px;
+    font-weight: 600;
+    cursor: pointer;
+    display: inline-flex;
+    align-items: center;
+    gap: 4px;
+    transition: var(--transition);
+}
+
+.audio-btn:hover {
+    background-color: var(--primary);
+    color: #0f172a;
+}
+
+.definition-box {
+    background-color: var(--bg-main);
+    border-left: 3px solid var(--primary);
+    padding: 12px 16px;
+    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
+    margin-bottom: 20px;
+}
+
+.def-label {
+    font-size: 11px;
+    font-weight: 700;
+    text-transform: uppercase;
+    color: var(--primary);
+    letter-spacing: 0.5px;
+    margin-bottom: 4px;
+}
+
+.def-text {
+    font-size: 14px;
+    color: var(--text-main);
+}
+
+.card-edit-grid {
+    display: flex;
+    flex-direction: column;
+    gap: 16px;
+    margin-bottom: 24px;
+}
+
+.input-styled {
+    width: 100%;
+    padding: 10px 14px;
+    background-color: var(--bg-input);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-sm);
+    color: var(--text-main);
+    font-size: 14px;
+    outline: none;
+    transition: var(--transition);
+}
+
+.input-styled:focus {
+    border-color: var(--border-focus);
+    box-shadow: 0 0 0 3px var(--primary-dim);
+}
+
+.field-group label {
+    display: block;
+    font-size: 12px;
+    font-weight: 600;
+    color: var(--text-muted);
+    margin-bottom: 5px;
+}
+
+.field-group .req {
+    color: var(--danger);
+}
+
+.field-row {
+    display: flex;
+    gap: 16px;
+}
+
+.flex-1 { flex: 1; }
+.flex-2 { flex: 2; }
+
+.suggestions-chips {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 6px;
+    margin-top: 6px;
+}
+
+.suggestion-chip {
+    font-size: 12px;
+    background-color: var(--bg-surface-hover);
+    color: var(--text-muted);
+    padding: 2px 8px;
+    border-radius: var(--radius-full);
+    cursor: pointer;
+    transition: var(--transition);
+    border: 1px solid transparent;
+}
+
+.suggestion-chip:hover {
+    border-color: var(--primary);
+    color: var(--primary);
+}
+
+.quick-tags {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 6px;
+    margin-top: 6px;
+}
+
+.tag-chip {
+    font-size: 11px;
+    background-color: var(--tag-bg);
+    color: var(--tag-text);
+    padding: 2px 8px;
+    border-radius: var(--radius-full);
+    cursor: pointer;
+    user-select: none;
+    transition: var(--transition);
+}
+
+.tag-chip:hover, .tag-chip.active {
+    background-color: var(--primary);
+    color: #0f172a;
+    font-weight: 600;
+}
+
+.result-actions {
+    display: flex;
+    justify-content: flex-end;
+}
+
+/* Vocabulary Section */
+.vocabulary-section {
+    display: flex;
+    flex-direction: column;
+    gap: 16px;
+}
+
+.section-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    flex-wrap: wrap;
+    gap: 12px;
+}
+
+.section-title-wrap {
+    display: flex;
+    align-items: baseline;
+    gap: 8px;
+}
+
+.section-title-wrap h3 {
+    font-size: 20px;
+    font-weight: 700;
+}
+
+.cards-count-label {
+    font-size: 13px;
+    color: var(--text-dim);
+}
+
+.search-mini-box input {
+    background-color: var(--bg-surface);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-sm);
+    padding: 8px 12px;
+    color: var(--text-main);
+    font-size: 13px;
+    outline: none;
+    min-width: 260px;
+    transition: var(--transition);
+}
+
+.search-mini-box input:focus {
+    border-color: var(--border-focus);
+}
+
+/* Tags Filter Bar */
+.tags-filter-bar {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 8px;
+}
+
+.filter-chip {
+    background-color: var(--bg-surface);
+    border: 1px solid var(--border-color);
+    color: var(--text-muted);
+    font-size: 12px;
+    font-weight: 600;
+    padding: 4px 12px;
+    border-radius: var(--radius-full);
+    cursor: pointer;
+    transition: var(--transition);
+}
+
+.filter-chip:hover {
+    border-color: var(--primary);
+    color: var(--primary);
+}
+
+.filter-chip.active {
+    background-color: var(--primary);
+    border-color: var(--primary);
+    color: #0f172a;
+}
+
+/* Cards List */
+.cards-list {
+    display: flex;
+    flex-direction: column;
+    gap: 12px;
+}
+
+.vocab-card {
+    background-color: var(--bg-card);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-md);
+    padding: 16px 20px;
+    box-shadow: var(--shadow-sm);
+    transition: var(--transition);
+    display: flex;
+    flex-direction: column;
+    gap: 10px;
+}
+
+.vocab-card:hover {
+    border-color: var(--border-focus);
+    box-shadow: var(--shadow-md);
+}
+
+.card-top {
+    display: flex;
+    justify-content: space-between;
+    align-items: flex-start;
+}
+
+.card-term-group {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    flex-wrap: wrap;
+}
+
+.card-term {
+    font-size: 18px;
+    font-weight: 700;
+    color: var(--text-main);
+}
+
+.card-phonetic {
+    font-size: 13px;
+    color: var(--primary);
+    font-family: monospace;
+}
+
+.card-pos {
+    font-size: 11px;
+    background-color: var(--bg-surface-hover);
+    color: var(--text-dim);
+    padding: 2px 6px;
+    border-radius: 4px;
+}
+
+.card-actions {
+    display: flex;
+    gap: 6px;
+}
+
+.card-translation {
+    font-size: 16px;
+    font-weight: 600;
+    color: var(--text-main);
+}
+
+.card-context {
+    font-size: 14px;
+    color: var(--text-muted);
+    font-style: italic;
+    background-color: var(--bg-main);
+    padding: 8px 12px;
+    border-radius: var(--radius-sm);
+    border-left: 2px solid var(--border-color);
+}
+
+.card-context mark {
+    background-color: var(--primary-dim);
+    color: var(--primary);
+    font-weight: 600;
+    padding: 0 4px;
+    border-radius: 2px;
+}
+
+.card-bottom {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    flex-wrap: wrap;
+    gap: 8px;
+    font-size: 12px;
+    color: var(--text-dim);
+}
+
+.card-tags {
+    display: flex;
+    gap: 6px;
+    flex-wrap: wrap;
+}
+
+.card-tag {
+    background-color: var(--tag-bg);
+    color: var(--tag-text);
+    padding: 2px 8px;
+    border-radius: var(--radius-full);
+    font-size: 11px;
+}
+
+.card-notes {
+    font-size: 12px;
+    color: #fbbf24;
+    display: flex;
+    align-items: center;
+    gap: 4px;
+}
+
+/* Empty state */
+.empty-state {
+    text-align: center;
+    padding: 48px 24px;
+    background-color: var(--bg-surface);
+    border: 1px dashed var(--border-color);
+    border-radius: var(--radius-md);
+    color: var(--text-muted);
+}
+
+.empty-icon {
+    font-size: 40px;
+    margin-bottom: 12px;
+}
+
+.empty-state h4 {
+    font-size: 16px;
+    color: var(--text-main);
+    margin-bottom: 6px;
+}
+
+.empty-state p {
+    font-size: 13px;
+    color: var(--text-dim);
+}
+
+/* Modal */
+.modal-backdrop {
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    background-color: rgba(0, 0, 0, 0.7);
+    backdrop-filter: blur(4px);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    z-index: 1000;
+    padding: 20px;
+}
+
+.modal-window {
+    background-color: var(--bg-surface);
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-lg);
+    width: 100%;
+    max-width: 520px;
+    box-shadow: var(--shadow-lg);
+    display: flex;
+    flex-direction: column;
+}
+
+.modal-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    padding: 16px 20px;
+    border-bottom: 1px solid var(--border-color);
+}
+
+.modal-header h3 {
+    font-size: 18px;
+    font-weight: 700;
+}
+
+.modal-body {
+    padding: 20px;
+    display: flex;
+    flex-direction: column;
+    gap: 14px;
+}
+
+.modal-footer {
+    display: flex;
+    justify-content: flex-end;
+    gap: 10px;
+    padding: 14px 20px;
+    border-top: 1px solid var(--border-color);
+}
+
+/* Responsive */
+@media (max-width: 640px) {
+    .navbar {
+        padding: 10px 14px;
+    }
+    .brand-sub {
+        display: none;
+    }
+    .main-content {
+        padding: 16px 12px;
+        gap: 24px;
+    }
+    .field-row {
+        flex-direction: column;
+    }
+    .res-term {
+        font-size: 22px;
+    }
+    .hotkey-hints {
+        display: none;
+    }
+    .search-mini-box input {
+        min-width: 100%;
+    }
+}
diff --git a/app/static/index.html b/app/static/index.html
new file mode 100644
index 0000000..953a637
--- /dev/null
+++ b/app/static/index.html
@@ -0,0 +1,220 @@
+<!DOCTYPE html>
+<html lang="ru">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Notes — Персональный тренажёр английского языка</title>
+    <link rel="stylesheet" href="/static/css/style.css">
+    <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📖</text></svg>">
+</head>
+<body>
+
+    <!-- Login Modal / Screen -->
+    <div id="auth-screen" class="auth-screen hidden">
+        <div class="auth-card">
+            <div class="auth-header">
+                <div class="app-logo">📖</div>
+                <h2>Вход в Notes</h2>
+                <p>Персональный словарь и тренажёр языка</p>
+            </div>
+            <form id="login-form">
+                <div class="form-group">
+                    <label for="username">Имя пользователя</label>
+                    <input type="text" id="username" autocomplete="username" required placeholder="admin" autofocus>
+                </div>
+                <div class="form-group">
+                    <label for="password">Пароль</label>
+                    <input type="password" id="password" autocomplete="current-password" required placeholder="••••••••">
+                </div>
+                <div id="auth-error" class="error-banner hidden"></div>
+                <button type="submit" id="login-btn" class="btn btn-primary btn-block">Войти в систему</button>
+            </form>
+            <div class="auth-footer">
+                <span>Защищённый контур: notes.qpid.pro</span>
+            </div>
+        </div>
+    </div>
+
+    <!-- Main Application UI -->
+    <div id="app-container" class="app-container hidden">
+        <!-- Top Navigation -->
+        <header class="navbar">
+            <div class="nav-brand">
+                <span class="brand-icon">📖</span>
+                <span class="brand-title">Notes</span>
+                <span class="brand-sub">English Lexicon</span>
+            </div>
+
+            <div class="nav-stats" id="nav-stats">
+                <span class="stat-badge" title="Всего слов в словаре">Всего: <strong id="stat-total">0</strong></span>
+                <span class="stat-badge stat-today" title="Добавлено сегодня">Сегодня: <strong id="stat-today">+0</strong></span>
+            </div>
+
+            <div class="nav-actions">
+                <button id="theme-toggle" class="icon-btn" title="Переключить тему">🌓</button>
+                <div class="user-profile">
+                    <span id="user-display-name" class="user-badge">user</span>
+                    <button id="logout-btn" class="btn btn-sm btn-outline" title="Выйти из аккаунта">Выход</button>
+                </div>
+            </div>
+        </header>
+
+        <main class="main-content">
+            <!-- Search & Translation Section -->
+            <section class="search-section">
+                <div class="search-box-wrapper">
+                    <div class="search-input-box">
+                        <span class="search-icon">🔍</span>
+                        <input type="text" id="term-input" placeholder="Введите слово, фразовый глагол или предложение..." autocomplete="off" autofocus>
+                        <button id="clear-search-btn" class="clear-btn hidden" title="Очистить (Esc)">✕</button>
+                        <button id="translate-btn" class="btn btn-primary translate-action-btn">Перевести</button>
+                    </div>
+
+                    <div class="hotkey-hints">
+                        <span class="hint-item"><kbd>Enter</kbd> перевод</span>
+                        <span class="hint-item"><kbd>Ctrl</kbd>+<kbd>Enter</kbd> сохранить</span>
+                        <span class="hint-item"><kbd>Esc</kbd> сброс</span>
+                        <span class="hint-item"><kbd>Space</kbd> / <kbd>🔊</kbd> озвучить</span>
+                    </div>
+                </div>
+
+                <!-- Loader -->
+                <div id="lookup-spinner" class="lookup-spinner hidden">
+                    <div class="spinner"></div>
+                    <span>Ищем толкование, произношение и перевод...</span>
+                </div>
+
+                <!-- Live Result Card -->
+                <div id="result-card" class="result-card hidden">
+                    <div class="result-header">
+                        <div class="term-title-row">
+                            <h2 id="res-term" class="res-term">reluctant</h2>
+                            <span id="res-phonetic" class="res-phonetic badge-pill">/rɪˈlʌktənt/</span>
+                            <span id="res-pos" class="res-pos badge-pill">Adjective</span>
+                            <button id="play-audio-btn" class="audio-btn" title="Прослушать произношение">
+                                🔊 <span class="audio-text">Слушать</span>
+                            </button>
+                        </div>
+                    </div>
+
+                    <div id="res-definition-box" class="definition-box">
+                        <div class="def-label">Толкование (English):</div>
+                        <p id="res-definition" class="def-text"></p>
+                    </div>
+
+                    <div class="card-edit-grid">
+                        <div class="field-group">
+                            <label for="edit-translation">Перевод на русский <span class="req">*</span></label>
+                            <input type="text" id="edit-translation" class="input-styled" placeholder="Основной перевод...">
+                            <div id="translation-suggestions" class="suggestions-chips"></div>
+                        </div>
+
+                        <div class="field-group">
+                            <label for="edit-context">Контекстное предложение (где встретилось?)</label>
+                            <input type="text" id="edit-context" class="input-styled" placeholder="Например: The switch drops the frame if the VLAN ID is invalid.">
+                        </div>
+
+                        <div class="field-row">
+                            <div class="field-group flex-2">
+                                <label for="edit-tags">Теги (через запятую)</label>
+                                <input type="text" id="edit-tags" class="input-styled" placeholder="general, phrasal-verb, networking">
+                                <div class="quick-tags" id="quick-tags-bar">
+                                    <span class="tag-chip" data-tag="general">#general</span>
+                                    <span class="tag-chip" data-tag="phrasal-verb">#phrasal-verb</span>
+                                    <span class="tag-chip" data-tag="idiom">#idiom</span>
+                                    <span class="tag-chip" data-tag="daily">#daily</span>
+                                    <span class="tag-chip" data-tag="tech">#tech</span>
+                                    <span class="tag-chip" data-tag="work">#work</span>
+                                </div>
+                            </div>
+
+                            <div class="field-group flex-1">
+                                <label for="edit-notes">Заметка / Мнемоника</label>
+                                <input type="text" id="edit-notes" class="input-styled" placeholder="Ассоциация...">
+                            </div>
+                        </div>
+                    </div>
+
+                    <div class="result-actions">
+                        <button id="save-card-btn" class="btn btn-success btn-lg">
+                            💾 Сохранить в словарь <span class="btn-subtext">(Ctrl + Enter)</span>
+                        </button>
+                    </div>
+                </div>
+            </section>
+
+            <!-- Vocabulary Notebook & History -->
+            <section class="vocabulary-section">
+                <div class="section-header">
+                    <div class="section-title-wrap">
+                        <h3>📚 Мой словарь</h3>
+                        <span id="cards-count-label" class="cards-count-label">(0 записей)</span>
+                    </div>
+
+                    <div class="list-controls">
+                        <div class="search-mini-box">
+                            <input type="text" id="filter-input" placeholder="Фильтр по слову, переводу, контексту...">
+                        </div>
+                    </div>
+                </div>
+
+                <!-- Active Tags Filter -->
+                <div id="tags-filter-bar" class="tags-filter-bar">
+                    <button class="filter-chip active" data-tag="">Все теги</button>
+                </div>
+
+                <!-- Cards Grid/List -->
+                <div id="cards-list" class="cards-list">
+                    <div class="empty-state" id="empty-state">
+                        <div class="empty-icon">🌱</div>
+                        <h4>Ваш словарь пока пуст</h4>
+                        <p>Введите первое слово или фразу в поле поиска выше и сохраните её!</p>
+                    </div>
+                </div>
+            </section>
+        </main>
+    </div>
+
+    <!-- Edit Card Modal -->
+    <div id="edit-modal" class="modal-backdrop hidden">
+        <div class="modal-window">
+            <div class="modal-header">
+                <h3>Редактирование карточки</h3>
+                <button id="close-modal-btn" class="icon-btn">✕</button>
+            </div>
+            <div class="modal-body">
+                <input type="hidden" id="modal-card-id">
+                <div class="form-group">
+                    <label>Слово / Фраза</label>
+                    <input type="text" id="modal-term" class="input-styled">
+                </div>
+                <div class="form-group">
+                    <label>Перевод на русский</label>
+                    <input type="text" id="modal-translation" class="input-styled">
+                </div>
+                <div class="form-group">
+                    <label>Контекстное предложение</label>
+                    <input type="text" id="modal-context" class="input-styled">
+                </div>
+                <div class="form-group">
+                    <label>Теги</label>
+                    <input type="text" id="modal-tags" class="input-styled">
+                </div>
+                <div class="form-group">
+                    <label>Заметки / Мнемоника</label>
+                    <input type="text" id="modal-notes" class="input-styled">
+                </div>
+            </div>
+            <div class="modal-footer">
+                <button id="modal-cancel-btn" class="btn btn-outline">Отмена</button>
+                <button id="modal-save-btn" class="btn btn-primary">Сохранить изменения</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Audio Element for native streaming -->
+    <audio id="global-audio-player" preload="none"></audio>
+
+    <script src="/static/js/app.js"></script>
+</body>
+</html>
diff --git a/app/static/js/app.js b/app/static/js/app.js
new file mode 100644
index 0000000..d2ed930
--- /dev/null
+++ b/app/static/js/app.js
@@ -0,0 +1,650 @@
+// Notes Application Frontend Logic
+document.addEventListener('DOMContentLoaded', () => {
+    // State
+    let currentUser = null;
+    let currentLookupData = null;
+    let allCards = [];
+    let selectedTag = '';
+    let searchQuery = '';
+
+    // Elements - Auth
+    const authScreen = document.getElementById('auth-screen');
+    const appContainer = document.getElementById('app-container');
+    const loginForm = document.getElementById('login-form');
+    const usernameInput = document.getElementById('username');
+    const passwordInput = document.getElementById('password');
+    const authError = document.getElementById('auth-error');
+    const loginBtn = document.getElementById('login-btn');
+    const logoutBtn = document.getElementById('logout-btn');
+    const userDisplayName = document.getElementById('user-display-name');
+
+    // Elements - Navbar & Stats
+    const themeToggle = document.getElementById('theme-toggle');
+    const statTotal = document.getElementById('stat-total');
+    const statToday = document.getElementById('stat-today');
+
+    // Elements - Search & Result
+    const termInput = document.getElementById('term-input');
+    const clearSearchBtn = document.getElementById('clear-search-btn');
+    const translateBtn = document.getElementById('translate-btn');
+    const lookupSpinner = document.getElementById('lookup-spinner');
+    const resultCard = document.getElementById('result-card');
+    const resTerm = document.getElementById('res-term');
+    const resPhonetic = document.getElementById('res-phonetic');
+    const resPos = document.getElementById('res-pos');
+    const playAudioBtn = document.getElementById('play-audio-btn');
+    const resDefinitionBox = document.getElementById('res-definition-box');
+    const resDefinition = document.getElementById('res-definition');
+    const editTranslation = document.getElementById('edit-translation');
+    const translationSuggestions = document.getElementById('translation-suggestions');
+    const editContext = document.getElementById('edit-context');
+    const editTags = document.getElementById('edit-tags');
+    const quickTagsBar = document.getElementById('quick-tags-bar');
+    const editNotes = document.getElementById('edit-notes');
+    const saveCardBtn = document.getElementById('save-card-btn');
+
+    // Elements - Vocabulary List
+    const filterInput = document.getElementById('filter-input');
+    const tagsFilterBar = document.getElementById('tags-filter-bar');
+    const cardsList = document.getElementById('cards-list');
+    const emptyState = document.getElementById('empty-state');
+    const cardsCountLabel = document.getElementById('cards-count-label');
+
+    // Elements - Modal
+    const editModal = document.getElementById('edit-modal');
+    const closeModalBtn = document.getElementById('close-modal-btn');
+    const modalCancelBtn = document.getElementById('modal-cancel-btn');
+    const modalSaveBtn = document.getElementById('modal-save-btn');
+    const modalCardId = document.getElementById('modal-card-id');
+    const modalTerm = document.getElementById('modal-term');
+    const modalTranslation = document.getElementById('modal-translation');
+    const modalContext = document.getElementById('modal-context');
+    const modalTags = document.getElementById('modal-tags');
+    const modalNotes = document.getElementById('modal-notes');
+
+    // Audio
+    const globalAudioPlayer = document.getElementById('global-audio-player');
+
+    // Theme Management
+    function initTheme() {
+        const savedTheme = localStorage.getItem('notes_theme') || 'dark';
+        document.documentElement.setAttribute('data-theme', savedTheme);
+        themeToggle.textContent = savedTheme === 'dark' ? '☀️' : '🌙';
+    }
+
+    themeToggle.addEventListener('click', () => {
+        const currentTheme = document.documentElement.getAttribute('data-theme') || 'dark';
+        const newTheme = currentTheme === 'dark' ? 'light' : 'dark';
+        document.documentElement.setAttribute('data-theme', newTheme);
+        localStorage.setItem('notes_theme', newTheme);
+        themeToggle.textContent = newTheme === 'dark' ? '☀️' : '🌙';
+    });
+
+    // Pronunciation Helper (Audio file or Web Speech API fallback)
+    function playAudio(text, audioUrl) {
+        if (audioUrl) {
+            globalAudioPlayer.src = audioUrl;
+            globalAudioPlayer.play().catch(() => {
+                fallbackSpeechSynthesis(text);
+            });
+        } else {
+            fallbackSpeechSynthesis(text);
+        }
+    }
+
+    function fallbackSpeechSynthesis(text) {
+        if ('speechSynthesis' in window) {
+            window.speechSynthesis.cancel();
+            const utterance = new SpeechSynthesisUtterance(text);
+            utterance.lang = 'en-US';
+            utterance.rate = 0.9;
+            window.speechSynthesis.speak(utterance);
+        }
+    }
+
+    // Auth Handlers
+    async function checkAuth() {
+        try {
+            const resp = await fetch('/api/me');
+            if (resp.ok) {
+                const data = await resp.json();
+                currentUser = data.user;
+                showApp();
+            } else {
+                showAuth();
+            }
+        } catch (e) {
+            showAuth();
+        }
+    }
+
+    function showAuth() {
+        authScreen.classList.remove('hidden');
+        appContainer.classList.add('hidden');
+        usernameInput.focus();
+    }
+
+    function showApp() {
+        authScreen.classList.add('hidden');
+        appContainer.classList.remove('hidden');
+        userDisplayName.textContent = currentUser ? currentUser.username : 'user';
+        termInput.focus();
+        loadStats();
+        loadCards();
+        loadTags();
+    }
+
+    loginForm.addEventListener('submit', async (e) => {
+        e.preventDefault();
+        authError.classList.add('hidden');
+        loginBtn.disabled = true;
+        loginBtn.textContent = 'Вход...';
+
+        try {
+            const resp = await fetch('/api/login', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({
+                    username: usernameInput.value.trim(),
+                    password: passwordInput.value
+                })
+            });
+
+            const data = await resp.json();
+            if (resp.ok) {
+                currentUser = data.user;
+                passwordInput.value = '';
+                showApp();
+            } else {
+                authError.textContent = data.detail || 'Ошибка авторизации';
+                authError.classList.remove('hidden');
+            }
+        } catch (err) {
+            authError.textContent = 'Ошибка сети. Проверьте подключение к серверу.';
+            authError.classList.remove('hidden');
+        } finally {
+            loginBtn.disabled = false;
+            loginBtn.textContent = 'Войти в систему';
+        }
+    });
+
+    logoutBtn.addEventListener('click', async () => {
+        try {
+            await fetch('/api/logout', { method: 'POST' });
+        } catch (e) {}
+        currentUser = null;
+        showAuth();
+    });
+
+    // Stats
+    async function loadStats() {
+        try {
+            const resp = await fetch('/api/stats');
+            if (resp.ok) {
+                const data = await resp.json();
+                statTotal.textContent = data.total_cards;
+                statToday.textContent = `+${data.today_added}`;
+            }
+        } catch (e) {}
+    }
+
+    // Search & Translate
+    async function performLookup() {
+        const query = termInput.value.trim();
+        if (!query) return;
+
+        lookupSpinner.classList.remove('hidden');
+        resultCard.classList.add('hidden');
+        translateBtn.disabled = true;
+
+        try {
+            const resp = await fetch(`/api/lookup?q=${encodeURIComponent(query)}`);
+            if (resp.status === 401) {
+                showAuth();
+                return;
+            }
+            if (!resp.ok) throw new Error('Ошибка словаря');
+
+            const data = await resp.json();
+            currentLookupData = data;
+            renderResultCard(data);
+        } catch (err) {
+            alert('Не удалось получить перевод. Попробуйте снова или введите перевод вручную.');
+        } finally {
+            lookupSpinner.classList.add('hidden');
+            translateBtn.disabled = false;
+        }
+    }
+
+    function renderResultCard(data) {
+        resTerm.textContent = data.query;
+
+        // Phonetic
+        if (data.phonetic) {
+            resPhonetic.textContent = data.phonetic;
+            resPhonetic.classList.remove('hidden');
+        } else {
+            resPhonetic.classList.add('hidden');
+        }
+
+        // Part of Speech
+        if (data.part_of_speech) {
+            resPos.textContent = data.part_of_speech;
+            resPos.classList.remove('hidden');
+        } else {
+            resPos.classList.add('hidden');
+        }
+
+        // Definitions
+        if (data.definitions && data.definitions.length > 0) {
+            resDefinition.textContent = data.definitions[0];
+            resDefinitionBox.classList.remove('hidden');
+        } else {
+            resDefinitionBox.classList.add('hidden');
+        }
+
+        // Translation field
+        editTranslation.value = data.translation || '';
+
+        // Translation suggestions chips
+        translationSuggestions.innerHTML = '';
+        if (data.translations_list && data.translations_list.length > 1) {
+            data.translations_list.forEach(t => {
+                const chip = document.createElement('span');
+                chip.className = 'suggestion-chip';
+                chip.textContent = t;
+                chip.addEventListener('click', () => {
+                    editTranslation.value = t;
+                });
+                translationSuggestions.appendChild(chip);
+            });
+        }
+
+        // Context: if user entered a sentence, put it in context field
+        if (data.is_sentence) {
+            editContext.value = data.query;
+        } else {
+            editContext.value = '';
+        }
+
+        // Auto-assign default tags
+        let defaultTags = ['general'];
+        if (data.is_sentence) {
+            defaultTags = ['phrase'];
+        } else if (data.query.includes(' ') && data.part_of_speech && data.part_of_speech.toLowerCase().includes('verb')) {
+            defaultTags = ['phrasal-verb'];
+        }
+        editTags.value = defaultTags.join(', ');
+        editNotes.value = '';
+
+        resultCard.classList.remove('hidden');
+        editTranslation.focus();
+    }
+
+    // Audio Play for Result Card
+    playAudioBtn.addEventListener('click', () => {
+        if (!currentLookupData) return;
+        playAudio(currentLookupData.query, currentLookupData.audio_url);
+    });
+
+    // Quick Tags Selector
+    quickTagsBar.addEventListener('click', (e) => {
+        if (e.target.classList.contains('tag-chip')) {
+            const tag = e.target.dataset.tag;
+            const currentTags = editTags.value.split(',').map(t => t.trim()).filter(Boolean);
+            if (!currentTags.includes(tag)) {
+                currentTags.push(tag);
+                editTags.value = currentTags.join(', ');
+            }
+        }
+    });
+
+    // Save Card
+    async function saveCurrentCard() {
+        if (!currentLookupData) return;
+        const term = currentLookupData.query;
+        const translation = editTranslation.value.trim();
+
+        if (!translation) {
+            alert('Пожалуйста, укажите перевод слова.');
+            editTranslation.focus();
+            return;
+        }
+
+        saveCardBtn.disabled = true;
+        saveCardBtn.textContent = 'Сохранение...';
+
+        try {
+            const payload = {
+                term: term,
+                translation: translation,
+                context_sentence: editContext.value.trim(),
+                phonetic: currentLookupData.phonetic || '',
+                audio_url: currentLookupData.audio_url || '',
+                part_of_speech: currentLookupData.part_of_speech || '',
+                definition_en: currentLookupData.definitions && currentLookupData.definitions.length ? currentLookupData.definitions[0] : '',
+                tags: editTags.value.trim() || 'general',
+                notes: editNotes.value.trim()
+            };
+
+            const resp = await fetch('/api/cards', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify(payload)
+            });
+
+            if (resp.ok) {
+                // Success feedback
+                saveCardBtn.textContent = '✅ Сохранено!';
+                setTimeout(() => {
+                    resultCard.classList.add('hidden');
+                    termInput.value = '';
+                    clearSearchBtn.classList.add('hidden');
+                    termInput.focus();
+                    saveCardBtn.textContent = '💾 Сохранить в словарь (Ctrl + Enter)';
+                    saveCardBtn.disabled = false;
+                }, 600);
+
+                loadCards();
+                loadStats();
+                loadTags();
+            } else {
+                throw new Error('Ошибка сохранения');
+            }
+        } catch (err) {
+            alert('Не удалось сохранить карточку. Попробуйте еще раз.');
+            saveCardBtn.disabled = false;
+            saveCardBtn.textContent = '💾 Сохранить в словарь (Ctrl + Enter)';
+        }
+    }
+
+    saveCardBtn.addEventListener('click', saveCurrentCard);
+
+    // Term Input controls
+    termInput.addEventListener('input', () => {
+        if (termInput.value.trim()) {
+            clearSearchBtn.classList.remove('hidden');
+        } else {
+            clearSearchBtn.classList.add('hidden');
+        }
+    });
+
+    clearSearchBtn.addEventListener('click', () => {
+        termInput.value = '';
+        clearSearchBtn.classList.add('hidden');
+        resultCard.classList.add('hidden');
+        termInput.focus();
+    });
+
+    translateBtn.addEventListener('click', performLookup);
+
+    // Global Hotkeys
+    document.addEventListener('keydown', (e) => {
+        // Ctrl+Enter or Cmd+Enter to Save Card
+        if ((e.ctrlKey || e.metaKey) && e.key === 'Enter') {
+            e.preventDefault();
+            if (!resultCard.classList.contains('hidden')) {
+                saveCurrentCard();
+            }
+            return;
+        }
+
+        // Enter in search input
+        if (e.key === 'Enter' && document.activeElement === termInput) {
+            e.preventDefault();
+            performLookup();
+            return;
+        }
+
+        // Esc to clear search or close modal
+        if (e.key === 'Escape') {
+            if (!editModal.classList.contains('hidden')) {
+                editModal.classList.add('hidden');
+            } else if (document.activeElement === termInput) {
+                termInput.value = '';
+                clearSearchBtn.classList.add('hidden');
+                resultCard.classList.add('hidden');
+            }
+            return;
+        }
+    });
+
+    // Vocabulary Cards & Tags
+    async function loadCards() {
+        try {
+            let url = `/api/cards?limit=150`;
+            if (searchQuery) url += `&search=${encodeURIComponent(searchQuery)}`;
+            if (selectedTag) url += `&tag=${encodeURIComponent(selectedTag)}`;
+
+            const resp = await fetch(url);
+            if (resp.status === 401) {
+                showAuth();
+                return;
+            }
+            if (resp.ok) {
+                const data = await resp.json();
+                allCards = data.cards;
+                cardsCountLabel.textContent = `(${data.total} записей)`;
+                renderCards(allCards);
+            }
+        } catch (e) {}
+    }
+
+    function renderCards(cards) {
+        cardsList.innerHTML = '';
+        if (!cards || cards.length === 0) {
+            emptyState.classList.remove('hidden');
+            cardsList.appendChild(emptyState);
+            return;
+        }
+        emptyState.classList.add('hidden');
+
+        cards.forEach(card => {
+            const cardEl = document.createElement('div');
+            cardEl.className = 'vocab-card';
+
+            // Format date
+            const cardDate = new Date(card.created_at);
+            const dateStr = cardDate.toLocaleDateString('ru-RU', {
+                day: 'numeric',
+                month: 'short',
+                hour: '2-digit',
+                minute: '2-digit'
+            });
+
+            // Format tags
+            const tagsList = (card.tags || '').split(',').map(t => t.trim()).filter(Boolean);
+            const tagsHtml = tagsList.map(t => `<span class="card-tag">#${escapeHtml(t)}</span>`).join('');
+
+            // Highlight context
+            let contextHtml = '';
+            if (card.context_sentence) {
+                let formattedContext = escapeHtml(card.context_sentence);
+                // Highlight term occurrence in context
+                const regex = new RegExp(`(${escapeRegExp(card.term)})`, 'gi');
+                formattedContext = formattedContext.replace(regex, '<mark>$1</mark>');
+                contextHtml = `<div class="card-context">“${formattedContext}”</div>`;
+            }
+
+            // Notes
+            let notesHtml = '';
+            if (card.notes) {
+                notesHtml = `<span class="card-notes" title="Заметка">💡 ${escapeHtml(card.notes)}</span>`;
+            }
+
+            cardEl.innerHTML = `
+                <div class="card-top">
+                    <div class="card-term-group">
+                        <span class="card-term">${escapeHtml(card.term)}</span>
+                        ${card.phonetic ? `<span class="card-phonetic">${escapeHtml(card.phonetic)}</span>` : ''}
+                        ${card.part_of_speech ? `<span class="card-pos">${escapeHtml(card.part_of_speech)}</span>` : ''}
+                        <button class="icon-btn play-card-audio-btn" title="Озвучить" data-term="${escapeHtml(card.term)}" data-audio="${escapeHtml(card.audio_url || '')}">🔊</button>
+                    </div>
+                    <div class="card-actions">
+                        <button class="icon-btn edit-card-btn" title="Редактировать" data-id="${card.id}">✏️</button>
+                        <button class="icon-btn delete-card-btn" title="Удалить" data-id="${card.id}">🗑️</button>
+                    </div>
+                </div>
+
+                <div class="card-translation">${escapeHtml(card.translation)}</div>
+                ${contextHtml}
+
+                <div class="card-bottom">
+                    <div class="card-tags">${tagsHtml}</div>
+                    <div style="display: flex; align-items: center; gap: 10px;">
+                        ${notesHtml}
+                        <span class="card-date">${dateStr}</span>
+                    </div>
+                </div>
+            `;
+
+            // Card Listeners
+            cardEl.querySelector('.play-card-audio-btn').addEventListener('click', (e) => {
+                const btn = e.currentTarget;
+                playAudio(btn.dataset.term, btn.dataset.audio);
+            });
+
+            cardEl.querySelector('.edit-card-btn').addEventListener('click', () => {
+                openEditModal(card);
+            });
+
+            cardEl.querySelector('.delete-card-btn').addEventListener('click', async () => {
+                if (confirm(`Удалить слово "${card.term}" из словаря?`)) {
+                    await deleteCard(card.id);
+                }
+            });
+
+            cardsList.appendChild(cardEl);
+        });
+    }
+
+    async function deleteCard(cardId) {
+        try {
+            const resp = await fetch(`/api/cards/${cardId}`, { method: 'DELETE' });
+            if (resp.ok) {
+                loadCards();
+                loadStats();
+                loadTags();
+            }
+        } catch (e) {
+            alert('Ошибка удаления карточки');
+        }
+    }
+
+    // Modal Edit
+    function openEditModal(card) {
+        modalCardId.value = card.id;
+        modalTerm.value = card.term;
+        modalTranslation.value = card.translation;
+        modalContext.value = card.context_sentence || '';
+        modalTags.value = card.tags || '';
+        modalNotes.value = card.notes || '';
+        editModal.classList.remove('hidden');
+        modalTranslation.focus();
+    }
+
+    closeModalBtn.addEventListener('click', () => editModal.classList.add('hidden'));
+    modalCancelBtn.addEventListener('click', () => editModal.classList.add('hidden'));
+
+    modalSaveBtn.addEventListener('click', async () => {
+        const id = modalCardId.value;
+        try {
+            const payload = {
+                term: modalTerm.value.trim(),
+                translation: modalTranslation.value.trim(),
+                context_sentence: modalContext.value.trim(),
+                tags: modalTags.value.trim(),
+                notes: modalNotes.value.trim()
+            };
+            const resp = await fetch(`/api/cards/${id}`, {
+                method: 'PUT',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify(payload)
+            });
+            if (resp.ok) {
+                editModal.classList.add('hidden');
+                loadCards();
+                loadTags();
+            } else {
+                alert('Не удалось обновить карточку.');
+            }
+        } catch (e) {
+            alert('Ошибка при сохранении.');
+        }
+    });
+
+    // Tag Filter Bar
+    async function loadTags() {
+        try {
+            const resp = await fetch('/api/tags');
+            if (resp.ok) {
+                const tags = await resp.json();
+                renderTagsFilter(tags);
+            }
+        } catch (e) {}
+    }
+
+    function renderTagsFilter(tags) {
+        tagsFilterBar.innerHTML = '';
+        
+        // "All tags" button
+        const allBtn = document.createElement('button');
+        allBtn.className = `filter-chip ${selectedTag === '' ? 'active' : ''}`;
+        allBtn.textContent = 'Все теги';
+        allBtn.addEventListener('click', () => {
+            selectedTag = '';
+            document.querySelectorAll('.filter-chip').forEach(b => b.classList.remove('active'));
+            allBtn.classList.add('active');
+            loadCards();
+        });
+        tagsFilterBar.appendChild(allBtn);
+
+        tags.forEach(({ tag, count }) => {
+            const btn = document.createElement('button');
+            btn.className = `filter-chip ${selectedTag === tag ? 'active' : ''}`;
+            btn.textContent = `#${tag} (${count})`;
+            btn.addEventListener('click', () => {
+                if (selectedTag === tag) {
+                    selectedTag = '';
+                    btn.classList.remove('active');
+                    allBtn.classList.add('active');
+                } else {
+                    selectedTag = tag;
+                    document.querySelectorAll('.filter-chip').forEach(b => b.classList.remove('active'));
+                    btn.classList.add('active');
+                }
+                loadCards();
+            });
+            tagsFilterBar.appendChild(btn);
+        });
+    }
+
+    // Mini search filter
+    let debounceTimer = null;
+    filterInput.addEventListener('input', () => {
+        clearTimeout(debounceTimer);
+        debounceTimer = setTimeout(() => {
+            searchQuery = filterInput.value.trim();
+            loadCards();
+        }, 250);
+    });
+
+    // Helper functions
+    function escapeHtml(str) {
+        if (!str) return '';
+        return str
+            .replace(/&/g, '&amp;')
+            .replace(/</g, '&lt;')
+            .replace(/>/g, '&gt;')
+            .replace(/"/g, '&quot;')
+            .replace(/'/g, '&#039;');
+    }
+
+    function escapeRegExp(string) {
+        return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    }
+
+    // Initialize
+    initTheme();
+    checkAuth();
+});
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..3f3bc01
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,17 @@
+annotated-doc==0.0.5
+annotated-types==0.8.0
+anyio==4.15.1
+certifi==2026.7.22
+click==8.5.0
+fastapi==0.141.1
+h11==0.16.0
+httpcore==1.0.9
+httpx==0.28.1
+idna==3.20
+pydantic==2.13.5
+pydantic_core==2.46.5
+python-multipart==0.0.32
+starlette==1.6.0
+typing-inspection==0.4.4
+typing_extensions==4.16.0
+uvicorn==0.53.0
diff --git a/scripts/run.sh b/scripts/run.sh
new file mode 100755
index 0000000..a876137
--- /dev/null
+++ b/scripts/run.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+set -e
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )/.." >/dev/null 2>&1 && pwd )"
+cd "$DIR"
+
+# Source virtualenv
+source venv/bin/activate
+
+# Default port 8002, host 127.0.0.1
+HOST="${HOST:-127.0.0.1}"
+PORT="${PORT:-8002}"
+
+exec uvicorn app.main:app --host "$HOST" --port "$PORT" --workers 2
diff --git a/scripts/setup_admin.py b/scripts/setup_admin.py
new file mode 100755
index 0000000..9f96ac2
--- /dev/null
+++ b/scripts/setup_admin.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+import sys
+import argparse
+from pathlib import Path
+
+# Add project root to sys.path
+BASE_DIR = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(BASE_DIR))
+
+from app.database import init_db, get_db
+from app.auth import create_user, hash_password
+
+def main():
+    parser = argparse.ArgumentParser(description="Manage admin users for Notes App")
+    parser.add_argument("--username", "-u", required=True, help="Username")
+    parser.add_argument("--password", "-p", required=True, help="Password")
+    args = parser.parse_args()
+
+    init_db()
+
+    username = args.username.strip()
+    password = args.password
+
+    pwd_hash, salt = hash_password(password)
+
+    with get_db() as conn:
+        existing = conn.execute("SELECT id FROM users WHERE username = ?", (username,)).fetchone()
+        if existing:
+            conn.execute(
+                "UPDATE users SET password_hash = ?, salt = ? WHERE id = ?",
+                (pwd_hash, salt, existing["id"])
+            )
+            print(f"Password updated successfully for existing user '{username}'.")
+        else:
+            conn.execute(
+                "INSERT INTO users (username, password_hash, salt) VALUES (?, ?, ?)",
+                (username, pwd_hash, salt)
+            )
+            print(f"User '{username}' created successfully.")
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/test_api.py b/tests/test_api.py
new file mode 100644
index 0000000..42caa7d
--- /dev/null
+++ b/tests/test_api.py
@@ -0,0 +1,175 @@
+import os
+import tempfile
+import pytest
+from pathlib import Path
+from fastapi.testclient import TestClient
+
+# Use temporary database for tests
+temp_db = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
+os.environ["DB_PATH"] = temp_db.name
+os.environ["ADMIN_USERNAME"] = "testadmin"
+os.environ["ADMIN_PASSWORD"] = "testpass12345"
+
+from app.main import app
+from app import config
+from app.database import init_db, get_db
+from app.auth import hash_password, verify_password, create_user, authenticate_user, ensure_admin_user
+
+config.ADMIN_USERNAME = "testadmin"
+config.ADMIN_PASSWORD = "testpass12345"
+
+client = TestClient(app)
+
+def setup_module():
+    init_db()
+    ensure_admin_user()
+
+def teardown_module():
+    try:
+        Path(temp_db.name).unlink(missing_ok=True)
+    except Exception:
+        pass
+
+def test_password_hashing():
+    pwd = "superSecretPassword123"
+    h, salt = hash_password(pwd)
+    assert verify_password(pwd, h, salt) is True
+    assert verify_password("wrongPassword", h, salt) is False
+
+def test_user_creation_and_auth():
+    uid = create_user("demo_user", "demo_pass_999")
+    assert uid > 0
+    auth = authenticate_user("demo_user", "demo_pass_999")
+    assert auth is not None
+    assert auth["username"] == "demo_user"
+
+    wrong = authenticate_user("demo_user", "wrong_pass")
+    assert wrong is None
+
+def test_unauthenticated_access_blocked():
+    # Attempting to access protected API without session
+    resp = client.get("/api/me")
+    assert resp.status_code == 401
+
+    resp = client.get("/api/cards")
+    assert resp.status_code == 401
+
+    resp = client.post("/api/cards", json={"term": "apple", "translation": "яблоко"})
+    assert resp.status_code == 401
+
+def test_login_and_card_crud_workflow():
+    # 1. Login with testadmin
+    resp = client.post("/api/login", json={"username": "testadmin", "password": "testpass12345"})
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["status"] == "ok"
+    assert "user" in data
+
+    # 2. Check /api/me
+    resp = client.get("/api/me")
+    assert resp.status_code == 200
+    assert resp.json()["user"]["username"] == "testadmin"
+
+    # 3. Create a card
+    card_payload = {
+        "term": "reluctant",
+        "translation": "неохотный, нежелающий",
+        "context_sentence": "He was reluctant to leave the room.",
+        "phonetic": "/rɪˈlʌktənt/",
+        "part_of_speech": "Adjective",
+        "definition_en": "Not wanting to take some action",
+        "tags": "general, daily",
+        "notes": "Remember: reluctant to do sth"
+    }
+    resp = client.post("/api/cards", json=card_payload)
+    assert resp.status_code == 200
+    created = resp.json()
+    card_id = created["id"]
+    assert created["term"] == "reluctant"
+
+    # 4. Get cards list
+    resp = client.get("/api/cards")
+    assert resp.status_code == 200
+    res_data = resp.json()
+    assert res_data["total"] >= 1
+    assert any(c["id"] == card_id for c in res_data["cards"])
+
+    # 5. Filter cards by search
+    resp = client.get("/api/cards?search=reluctant")
+    assert resp.status_code == 200
+    assert resp.json()["total"] >= 1
+
+    # 6. Filter cards by tag
+    resp = client.get("/api/cards?tag=general")
+    assert resp.status_code == 200
+    assert resp.json()["total"] >= 1
+
+    # 7. Check tags list
+    resp = client.get("/api/tags")
+    assert resp.status_code == 200
+    tags = resp.json()
+    tag_names = [t["tag"] for t in tags]
+    assert "general" in tag_names
+    assert "daily" in tag_names
+
+    # 8. Update card
+    update_payload = {
+        "translation": "неохотный, сопротивляющийся",
+        "notes": "Updated note"
+    }
+    resp = client.put(f"/api/cards/{card_id}", json=update_payload)
+    assert resp.status_code == 200
+    updated = resp.json()
+    assert updated["translation"] == "неохотный, сопротивляющийся"
+    assert updated["notes"] == "Updated note"
+
+    # 9. Check stats
+    resp = client.get("/api/stats")
+    assert resp.status_code == 200
+    stats = resp.json()
+    assert stats["total_cards"] >= 1
+    assert stats["today_added"] >= 1
+
+    # 10. Delete card
+    resp = client.delete(f"/api/cards/{card_id}")
+    assert resp.status_code == 200
+    assert resp.json()["status"] == "ok"
+
+    # Verify deleted
+    resp = client.get("/api/cards")
+    assert not any(c["id"] == card_id for c in resp.json()["cards"])
+
+    # 11. Logout
+    resp = client.post("/api/logout")
+    assert resp.status_code == 200
+
+    # Verify session ended
+    resp = client.get("/api/me")
+    assert resp.status_code == 401
+
+def test_login_rate_limiting():
+    # Attempt multiple failed logins from the same client
+    for _ in range(5):
+        resp = client.post("/api/login", json={"username": "testadmin", "password": "wrong_password_999"})
+        assert resp.status_code == 401
+
+    # 6th attempt should be rate limited (429)
+    resp = client.post("/api/login", json={"username": "testadmin", "password": "wrong_password_999"})
+    assert resp.status_code == 429
+
+def test_lookup_endpoint_authenticated():
+    from app.auth import _login_failures
+    _login_failures.clear()
+
+    # Login first
+    resp = client.post("/api/login", json={"username": "testadmin", "password": "testpass12345"})
+    assert resp.status_code == 200
+
+    resp = client.get("/api/lookup?q=reluctant")
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["query"] == "reluctant"
+    assert "translation" in data
+    assert "phonetic" in data
+    assert len(data["translation"]) > 0
+