diff --git a/backend/alembic/versions/002_add_system_settings.py b/backend/alembic/versions/002_add_system_settings.py
new file mode 100644
index 0000000..850e03a
--- /dev/null
+++ b/backend/alembic/versions/002_add_system_settings.py
@@ -0,0 +1,41 @@
+"""Add system_settings table
+
+Revision ID: 002_system_settings
+Revises: 001_initial
+Create Date: 2026-04-02
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "002_system_settings"
+down_revision = "001_initial"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "system_settings",
+        sa.Column("id", sa.Integer, primary_key=True, autoincrement=True),
+        sa.Column("key", sa.String(100), unique=True, nullable=False, index=True),
+        sa.Column("value", sa.Text, nullable=False, server_default=""),
+        sa.Column("description", sa.String(255)),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+    )
+
+    # Seed default settings
+    op.execute("""
+        INSERT INTO system_settings (key, value, description) VALUES
+        ('platform_name', '天普零碳园区智慧能源管理平台', '平台名称'),
+        ('data_retention_days', '365', '数据保留天数'),
+        ('alarm_auto_resolve_minutes', '30', '告警自动解除时间(分钟)'),
+        ('simulator_interval_seconds', '15', '模拟器采集间隔(秒)'),
+        ('notification_email_enabled', 'false', '是否启用邮件通知'),
+        ('notification_email_smtp', '', 'SMTP服务器地址'),
+        ('report_auto_schedule_enabled', 'false', '是否启用自动报表'),
+        ('timezone', 'Asia/Shanghai', '系统时区')
+    """)
+
+
+def downgrade() -> None:
+    op.drop_table("system_settings")
diff --git a/backend/app/api/router.py b/backend/app/api/router.py
index 4303105..aad9ae6 100644
--- a/backend/app/api/router.py
+++ b/backend/app/api/router.py
@@ -1,5 +1,5 @@
 from fastapi import APIRouter
-from app.api.v1 import auth, users, devices, energy, monitoring, alarms, reports, carbon, dashboard, collectors, websocket
+from app.api.v1 import auth, users, devices, energy, monitoring, alarms, reports, carbon, dashboard, collectors, websocket, audit, settings
 
 api_router = APIRouter(prefix="/api/v1")
 
@@ -14,3 +14,5 @@ api_router.include_router(carbon.router)
 api_router.include_router(dashboard.router)
 api_router.include_router(collectors.router)
 api_router.include_router(websocket.router)
+api_router.include_router(audit.router)
+api_router.include_router(settings.router)
diff --git a/backend/app/api/v1/alarms.py b/backend/app/api/v1/alarms.py
index 7023fdb..aaf6722 100644
--- a/backend/app/api/v1/alarms.py
+++ b/backend/app/api/v1/alarms.py
@@ -7,6 +7,7 @@ from app.core.database import get_db
 from app.core.deps import get_current_user, require_roles
 from app.models.alarm import AlarmRule, AlarmEvent
 from app.models.user import User
+from app.services.audit import log_audit
 
 router = APIRouter(prefix="/alarms", tags=["告警管理"])
 
@@ -107,6 +108,7 @@ async def acknowledge_event(event_id: int, db: AsyncSession = Depends(get_db), u
     event.status = "acknowledged"
     event.acknowledged_by = user.id
     event.acknowledged_at = datetime.now(timezone.utc)
+    await log_audit(db, user.id, "acknowledge", "alarm", detail=f"确认告警 #{event_id}")
     return {"message": "已确认"}
 
 
@@ -119,6 +121,7 @@ async def resolve_event(event_id: int, note: str = "", db: AsyncSession = Depend
     event.status = "resolved"
     event.resolved_at = datetime.now(timezone.utc)
     event.resolve_note = note
+    await log_audit(db, user.id, "resolve", "alarm", detail=f"解决告警 #{event_id}")
     return {"message": "已解决"}
 
 
diff --git a/backend/app/api/v1/audit.py b/backend/app/api/v1/audit.py
new file mode 100644
index 0000000..7a13178
--- /dev/null
+++ b/backend/app/api/v1/audit.py
@@ -0,0 +1,76 @@
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select, func
+from datetime import datetime
+from app.core.database import get_db
+from app.core.deps import get_current_user, require_roles
+from app.models.user import User, AuditLog
+
+router = APIRouter(prefix="/audit", tags=["审计日志"])
+
+
+@router.get("/logs")
+async def list_audit_logs(
+    user_id: int | None = None,
+    action: str | None = None,
+    resource: str | None = None,
+    start_time: str | None = None,
+    end_time: str | None = None,
+    page: int = Query(1, ge=1),
+    page_size: int = Query(20, ge=1, le=100),
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(require_roles("admin", "energy_manager")),
+):
+    """Return paginated audit logs with optional filters."""
+    query = select(
+        AuditLog.id,
+        AuditLog.user_id,
+        User.username,
+        AuditLog.action,
+        AuditLog.resource,
+        AuditLog.detail,
+        AuditLog.ip_address,
+        AuditLog.created_at,
+    ).outerjoin(User, AuditLog.user_id == User.id)
+
+    if user_id is not None:
+        query = query.where(AuditLog.user_id == user_id)
+    if action:
+        query = query.where(AuditLog.action == action)
+    if resource:
+        query = query.where(AuditLog.resource == resource)
+    if start_time:
+        try:
+            st = datetime.fromisoformat(start_time)
+            query = query.where(AuditLog.created_at >= st)
+        except ValueError:
+            pass
+    if end_time:
+        try:
+            et = datetime.fromisoformat(end_time)
+            query = query.where(AuditLog.created_at <= et)
+        except ValueError:
+            pass
+
+    # Count
+    count_q = select(func.count()).select_from(query.subquery())
+    total = (await db.execute(count_q)).scalar()
+
+    # Paginate
+    query = query.order_by(AuditLog.created_at.desc()).offset((page - 1) * page_size).limit(page_size)
+    result = await db.execute(query)
+
+    items = []
+    for row in result.all():
+        items.append({
+            "id": row.id,
+            "user_id": row.user_id,
+            "username": row.username or "-",
+            "action": row.action,
+            "resource": row.resource,
+            "detail": row.detail,
+            "ip_address": row.ip_address,
+            "created_at": str(row.created_at) if row.created_at else None,
+        })
+
+    return {"total": total, "items": items}
diff --git a/backend/app/api/v1/auth.py b/backend/app/api/v1/auth.py
index 5936659..38bdf90 100644
--- a/backend/app/api/v1/auth.py
+++ b/backend/app/api/v1/auth.py
@@ -1,5 +1,5 @@
 from datetime import datetime, timezone
-from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi import APIRouter, Depends, HTTPException, Request, status
 from fastapi.security import OAuth2PasswordRequestForm
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
@@ -8,6 +8,7 @@ from app.core.database import get_db
 from app.core.security import verify_password, create_access_token, hash_password
 from app.core.deps import get_current_user
 from app.models.user import User
+from app.services.audit import log_audit
 
 router = APIRouter(prefix="/auth", tags=["认证"])
 
@@ -27,7 +28,7 @@ class RegisterRequest(BaseModel):
 
 
 @router.post("/login", response_model=Token)
-async def login(form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession = Depends(get_db)):
+async def login(request: Request, form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession = Depends(get_db)):
     result = await db.execute(select(User).where(User.username == form.username))
     user = result.scalar_one_or_none()
     if not user or not verify_password(form.password, user.hashed_password):
@@ -36,6 +37,8 @@ async def login(form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession =
         raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="账号已禁用")
     user.last_login = datetime.now(timezone.utc)
     token = create_access_token({"sub": str(user.id), "role": user.role})
+    client_ip = request.client.host if request.client else None
+    await log_audit(db, user.id, "login", "auth", detail=f"用户 {user.username} 登录", ip_address=client_ip)
     return Token(
         access_token=token,
         user={"id": user.id, "username": user.username, "full_name": user.full_name, "role": user.role}
diff --git a/backend/app/api/v1/devices.py b/backend/app/api/v1/devices.py
index 383cd90..4397b60 100644
--- a/backend/app/api/v1/devices.py
+++ b/backend/app/api/v1/devices.py
@@ -6,6 +6,7 @@ from app.core.database import get_db
 from app.core.deps import get_current_user, require_roles
 from app.models.device import Device, DeviceType, DeviceGroup
 from app.models.user import User
+from app.services.audit import log_audit
 
 router = APIRouter(prefix="/devices", tags=["设备管理"])
 
@@ -98,6 +99,7 @@ async def create_device(data: DeviceCreate, db: AsyncSession = Depends(get_db),
     device = Device(**data.model_dump())
     db.add(device)
     await db.flush()
+    await log_audit(db, user.id, "create", "device", detail=f"创建设备 {data.name} ({data.code})")
     return _device_to_dict(device)
 
 
@@ -107,8 +109,10 @@ async def update_device(device_id: int, data: DeviceUpdate, db: AsyncSession = D
     device = result.scalar_one_or_none()
     if not device:
         raise HTTPException(status_code=404, detail="设备不存在")
-    for k, v in data.model_dump(exclude_unset=True).items():
+    updates = data.model_dump(exclude_unset=True)
+    for k, v in updates.items():
         setattr(device, k, v)
+    await log_audit(db, user.id, "update", "device", detail=f"更新设备 {device.name}: {', '.join(updates.keys())}")
     return _device_to_dict(device)
 
 
diff --git a/backend/app/api/v1/reports.py b/backend/app/api/v1/reports.py
index 9e0ac14..411b7ca 100644
--- a/backend/app/api/v1/reports.py
+++ b/backend/app/api/v1/reports.py
@@ -13,6 +13,7 @@ from app.core.deps import get_current_user
 from app.models.report import ReportTemplate, ReportTask
 from app.models.user import User
 from app.services.report_generator import ReportGenerator, REPORTS_DIR
+from app.services.audit import log_audit
 
 logger = logging.getLogger(__name__)
 
@@ -184,6 +185,7 @@ async def run_task(
         task.file_path = filepath
         task.last_run = datetime.now()
         await db.flush()
+        await log_audit(db, user.id, "export", "report", detail=f"运行报表任务 #{task_id}")
         logger.info(f"Report task {task_id} completed: {filepath}")
         return {"message": "报表生成完成", "task_id": task.id, "mode": "sync", "status": "completed"}
     except Exception as e:
@@ -286,6 +288,7 @@ async def generate_quick_report(
         raise HTTPException(status_code=500, detail=f"报表生成失败: {str(e)}")
 
     filename = Path(filepath).name
+    await log_audit(db, user.id, "export", "report", detail=f"生成报表: {req.report_type} ({req.export_format})")
     return {
         "message": "报表生成成功",
         "filename": filename,
diff --git a/backend/app/api/v1/settings.py b/backend/app/api/v1/settings.py
new file mode 100644
index 0000000..fcede7e
--- /dev/null
+++ b/backend/app/api/v1/settings.py
@@ -0,0 +1,84 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+from pydantic import BaseModel
+from app.core.database import get_db
+from app.core.deps import get_current_user, require_roles
+from app.models.user import User
+from app.models.setting import SystemSetting
+from app.services.audit import log_audit
+
+router = APIRouter(prefix="/settings", tags=["系统设置"])
+
+# Default settings — used when keys are missing from DB
+DEFAULTS: dict[str, str] = {
+    "platform_name": "天普零碳园区智慧能源管理平台",
+    "data_retention_days": "365",
+    "alarm_auto_resolve_minutes": "30",
+    "simulator_interval_seconds": "15",
+    "notification_email_enabled": "false",
+    "notification_email_smtp": "",
+    "report_auto_schedule_enabled": "false",
+    "timezone": "Asia/Shanghai",
+}
+
+
+class SettingsUpdate(BaseModel):
+    platform_name: str | None = None
+    data_retention_days: int | None = None
+    alarm_auto_resolve_minutes: int | None = None
+    simulator_interval_seconds: int | None = None
+    notification_email_enabled: bool | None = None
+    notification_email_smtp: str | None = None
+    report_auto_schedule_enabled: bool | None = None
+    timezone: str | None = None
+
+
+@router.get("")
+async def get_settings(
+    db: AsyncSession = Depends(get_db),
+    user: User = Depends(get_current_user),
+):
+    """Return all platform settings as a flat dict."""
+    result = await db.execute(select(SystemSetting))
+    db_settings = {s.key: s.value for s in result.scalars().all()}
+    # Merge defaults with DB values
+    merged = {**DEFAULTS, **db_settings}
+    # Cast types for frontend
+    return {
+        "platform_name": merged["platform_name"],
+        "data_retention_days": int(merged["data_retention_days"]),
+        "alarm_auto_resolve_minutes": int(merged["alarm_auto_resolve_minutes"]),
+        "simulator_interval_seconds": int(merged["simulator_interval_seconds"]),
+        "notification_email_enabled": merged["notification_email_enabled"] == "true",
+        "notification_email_smtp": merged["notification_email_smtp"],
+        "report_auto_schedule_enabled": merged["report_auto_schedule_enabled"] == "true",
+        "timezone": merged["timezone"],
+    }
+
+
+@router.put("")
+async def update_settings(
+    data: SettingsUpdate,
+    db: AsyncSession = Depends(get_db),
+    user: User = Depends(require_roles("admin")),
+):
+    """Update platform settings (admin only)."""
+    updates = data.model_dump(exclude_unset=True)
+    changed_keys = []
+    for key, value in updates.items():
+        str_value = str(value).lower() if isinstance(value, bool) else str(value)
+        result = await db.execute(select(SystemSetting).where(SystemSetting.key == key))
+        setting = result.scalar_one_or_none()
+        if setting:
+            setting.value = str_value
+        else:
+            db.add(SystemSetting(key=key, value=str_value))
+        changed_keys.append(key)
+
+    await log_audit(
+        db, user.id, "update", "system",
+        detail=f"更新系统设置: {', '.join(changed_keys)}",
+    )
+
+    return {"message": "设置已更新"}
diff --git a/backend/app/api/v1/users.py b/backend/app/api/v1/users.py
index 04f60aa..1cb6b39 100644
--- a/backend/app/api/v1/users.py
+++ b/backend/app/api/v1/users.py
@@ -6,6 +6,7 @@ from app.core.database import get_db
 from app.core.deps import get_current_user, require_roles
 from app.core.security import hash_password
 from app.models.user import User, Role
+from app.services.audit import log_audit
 
 router = APIRouter(prefix="/users", tags=["用户管理"])
 
@@ -58,6 +59,7 @@ async def create_user(data: UserCreate, db: AsyncSession = Depends(get_db), user
     )
     db.add(new_user)
     await db.flush()
+    await log_audit(db, user.id, "create", "user", detail=f"创建用户 {data.username}")
     return {"id": new_user.id, "username": new_user.username}
 
 
@@ -67,8 +69,10 @@ async def update_user(user_id: int, data: UserUpdate, db: AsyncSession = Depends
     target = result.scalar_one_or_none()
     if not target:
         raise HTTPException(status_code=404, detail="用户不存在")
-    for k, v in data.model_dump(exclude_unset=True).items():
+    updates = data.model_dump(exclude_unset=True)
+    for k, v in updates.items():
         setattr(target, k, v)
+    await log_audit(db, admin.id, "update", "user", detail=f"更新用户 {target.username}: {', '.join(updates.keys())}")
     return {"message": "已更新"}
 
 
diff --git a/backend/app/core/config.py b/backend/app/core/config.py
index 8d191f5..02a215a 100644
--- a/backend/app/core/config.py
+++ b/backend/app/core/config.py
@@ -23,6 +23,17 @@ class Settings(BaseSettings):
     CELERY_ENABLED: bool = False  # Set True when Celery worker is running
     USE_SIMULATOR: bool = True  # True=simulator mode, False=real IoT collectors
 
+    # SMTP Email settings
+    SMTP_HOST: str = ""
+    SMTP_PORT: int = 587
+    SMTP_USER: str = ""
+    SMTP_PASSWORD: str = ""
+    SMTP_FROM: str = "noreply@tianpu-ems.com"
+    SMTP_ENABLED: bool = False
+
+    # Platform URL for links in emails
+    PLATFORM_URL: str = "http://localhost:3000"
+
     @property
     def DATABASE_URL_SYNC(self) -> str:
         """Derive synchronous URL from async DATABASE_URL for Alembic."""
diff --git a/backend/app/main.py b/backend/app/main.py
index 6c44814..77c80d5 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -8,6 +8,7 @@ from app.api.router import api_router
 from app.api.v1.websocket import start_broadcast_task, stop_broadcast_task
 from app.core.config import get_settings
 from app.services.simulator import DataSimulator
+from app.services.report_scheduler import start_scheduler, stop_scheduler
 from app.collectors.manager import CollectorManager
 
 settings = get_settings()
@@ -28,7 +29,9 @@ async def lifespan(app: FastAPI):
         collector_manager = CollectorManager()
         await collector_manager.start()
     start_broadcast_task()
+    await start_scheduler()
     yield
+    await stop_scheduler()
     stop_broadcast_task()
     if settings.USE_SIMULATOR:
         await simulator.stop()
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index 64d9395..d340bc6 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -4,6 +4,7 @@ from app.models.energy import EnergyData, EnergyDailySummary
 from app.models.alarm import AlarmRule, AlarmEvent
 from app.models.carbon import CarbonEmission, EmissionFactor
 from app.models.report import ReportTemplate, ReportTask
+from app.models.setting import SystemSetting
 
 __all__ = [
     "User", "Role", "AuditLog",
@@ -12,4 +13,5 @@ __all__ = [
     "AlarmRule", "AlarmEvent",
     "CarbonEmission", "EmissionFactor",
     "ReportTemplate", "ReportTask",
+    "SystemSetting",
 ]
diff --git a/backend/app/models/setting.py b/backend/app/models/setting.py
new file mode 100644
index 0000000..ac0c89e
--- /dev/null
+++ b/backend/app/models/setting.py
@@ -0,0 +1,13 @@
+from sqlalchemy import Column, Integer, String, Text, DateTime
+from sqlalchemy.sql import func
+from app.core.database import Base
+
+
+class SystemSetting(Base):
+    __tablename__ = "system_settings"
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    key = Column(String(100), unique=True, nullable=False, index=True)
+    value = Column(Text, nullable=False, default="")
+    description = Column(String(255))
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
diff --git a/backend/app/services/alarm_checker.py b/backend/app/services/alarm_checker.py
index 2309b29..fdb7678 100644
--- a/backend/app/services/alarm_checker.py
+++ b/backend/app/services/alarm_checker.py
@@ -1,13 +1,111 @@
 """告警检测服务 - 根据告警规则检查最新数据，生成/自动恢复告警事件"""
+import asyncio
 import logging
 from datetime import datetime, timezone, timedelta
+from pathlib import Path
 from sqlalchemy import select, and_
 from sqlalchemy.ext.asyncio import AsyncSession
 from app.models.alarm import AlarmRule, AlarmEvent
 from app.models.energy import EnergyData
+from app.models.device import Device
 
 logger = logging.getLogger("alarm_checker")
 
+# Alarm email template path
+_ALARM_TEMPLATE_PATH = Path(__file__).resolve().parent.parent / "templates" / "alarm_email.html"
+
+# Severity display config
+_SEVERITY_CONFIG = {
+    "critical": {
+        "label": "紧急告警",
+        "badge_color": "#d32f2f",
+        "bg_color": "#ffebee",
+        "text_color": "#c62828",
+    },
+    "major": {
+        "label": "重要告警",
+        "badge_color": "#e65100",
+        "bg_color": "#fff3e0",
+        "text_color": "#e65100",
+    },
+    "warning": {
+        "label": "一般告警",
+        "badge_color": "#f9a825",
+        "bg_color": "#fffde7",
+        "text_color": "#f57f17",
+    },
+}
+
+
+async def _send_alarm_email(
+    rule: AlarmRule, event: AlarmEvent, device_id: int, session: AsyncSession
+):
+    """Send alarm notification email if configured."""
+    from app.services.email_service import send_email
+    from app.core.config import get_settings
+
+    # Check if email is in notify_channels
+    channels = rule.notify_channels or []
+    if "email" not in channels:
+        return
+
+    # Get email targets from notify_targets
+    targets = rule.notify_targets or {}
+    emails = targets.get("emails", []) if isinstance(targets, dict) else []
+    # If notify_targets is a list of strings (emails directly)
+    if isinstance(targets, list):
+        emails = [t for t in targets if isinstance(t, str) and "@" in t]
+
+    if not emails:
+        logger.debug(f"No email recipients for alarm rule '{rule.name}', skipping.")
+        return
+
+    # Fetch device info
+    dev_result = await session.execute(select(Device).where(Device.id == device_id))
+    device = dev_result.scalar_one_or_none()
+    device_name = device.name if device else f"设备#{device_id}"
+    device_code = device.code if device else "N/A"
+
+    settings = get_settings()
+    severity_cfg = _SEVERITY_CONFIG.get(rule.severity, _SEVERITY_CONFIG["warning"])
+
+    # Build threshold string
+    if rule.condition == "range_out":
+        threshold_str = f"[{rule.threshold_low}, {rule.threshold_high}]"
+    else:
+        threshold_str = str(rule.threshold)
+
+    # Format triggered time in Beijing timezone
+    triggered_time = event.triggered_at or datetime.now(timezone.utc)
+    triggered_beijing = triggered_time + timedelta(hours=8)
+    triggered_str = triggered_beijing.strftime("%Y-%m-%d %H:%M:%S")
+
+    # Load and render template
+    try:
+        template_html = _ALARM_TEMPLATE_PATH.read_text(encoding="utf-8")
+    except FileNotFoundError:
+        logger.error("Alarm email template not found, skipping email.")
+        return
+
+    body_html = template_html.format(
+        severity_label=severity_cfg["label"],
+        severity_badge_color=severity_cfg["badge_color"],
+        severity_bg_color=severity_cfg["bg_color"],
+        severity_text_color=severity_cfg["text_color"],
+        title=event.title,
+        device_name=device_name,
+        device_code=device_code,
+        data_type=rule.data_type,
+        current_value=str(event.value),
+        threshold_str=threshold_str,
+        triggered_at=triggered_str,
+        description=event.description or "",
+        platform_url=settings.PLATFORM_URL,
+    )
+
+    subject = f"[{severity_cfg['label']}] {event.title} - 天普EMS告警通知"
+    asyncio.create_task(send_email(to=emails, subject=subject, body_html=body_html))
+
 # Rate limit: don't create duplicate events for the same rule+device within this window
 RATE_LIMIT_MINUTES = 5
 
@@ -140,6 +238,9 @@ async def check_alarms(session: AsyncSession):
                     f"value={dp.value} threshold={threshold_str}"
                 )
 
+                # Send email notification (non-blocking)
+                await _send_alarm_email(rule, event, device_id, session)
+
             elif not triggered and active_event:
                 # Auto-resolve
                 active_event.status = "resolved"
diff --git a/backend/app/services/audit.py b/backend/app/services/audit.py
new file mode 100644
index 0000000..feffea8
--- /dev/null
+++ b/backend/app/services/audit.py
@@ -0,0 +1,32 @@
+from sqlalchemy.ext.asyncio import AsyncSession
+from app.models.user import AuditLog
+
+
+async def log_audit(
+    db: AsyncSession,
+    user_id: int | None,
+    action: str,
+    resource: str,
+    detail: str = "",
+    ip_address: str | None = None,
+):
+    """Write an audit log entry.
+
+    Args:
+        db: async database session (must be flushed/committed by caller)
+        user_id: ID of the acting user (None for system actions)
+        action: one of login, create, update, delete, export, view,
+                acknowledge, resolve
+        resource: one of user, device, alarm, report, system, auth
+        detail: human-readable description
+        ip_address: client IP if available
+    """
+    entry = AuditLog(
+        user_id=user_id,
+        action=action,
+        resource=resource,
+        detail=detail,
+        ip_address=ip_address,
+    )
+    db.add(entry)
+    # Don't flush here — let the caller's transaction handle it
diff --git a/backend/app/services/email_service.py b/backend/app/services/email_service.py
new file mode 100644
index 0000000..bd3d1d4
--- /dev/null
+++ b/backend/app/services/email_service.py
@@ -0,0 +1,105 @@
+"""邮件发送服务 - SMTP email sending for alarm notifications and report delivery."""
+import logging
+import smtplib
+import ssl
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+from email.mime.base import MIMEBase
+from email import encoders
+from pathlib import Path
+from typing import Optional
+
+from app.core.config import get_settings
+
+logger = logging.getLogger("email_service")
+
+
+async def send_email(
+    to: list[str],
+    subject: str,
+    body_html: str,
+    attachments: Optional[list[str]] = None,
+) -> bool:
+    """
+    Send an email via SMTP.
+
+    Args:
+        to: List of recipient email addresses.
+        subject: Email subject line.
+        body_html: HTML body content.
+        attachments: Optional list of file paths to attach.
+
+    Returns:
+        True if sent successfully, False otherwise.
+    """
+    settings = get_settings()
+
+    if not settings.SMTP_ENABLED:
+        logger.warning("SMTP is not enabled (SMTP_ENABLED=False). Skipping email send.")
+        return False
+
+    if not settings.SMTP_HOST:
+        logger.warning("SMTP_HOST is not configured. Skipping email send.")
+        return False
+
+    if not to:
+        logger.warning("No recipients specified. Skipping email send.")
+        return False
+
+    try:
+        msg = MIMEMultipart("mixed")
+        msg["From"] = settings.SMTP_FROM
+        msg["To"] = ", ".join(to)
+        msg["Subject"] = subject
+
+        # HTML body
+        html_part = MIMEText(body_html, "html", "utf-8")
+        msg.attach(html_part)
+
+        # Attachments
+        if attachments:
+            for filepath in attachments:
+                path = Path(filepath)
+                if not path.exists():
+                    logger.warning(f"Attachment not found, skipping: {filepath}")
+                    continue
+
+                with open(path, "rb") as f:
+                    part = MIMEBase("application", "octet-stream")
+                    part.set_payload(f.read())
+                encoders.encode_base64(part)
+                part.add_header(
+                    "Content-Disposition",
+                    f'attachment; filename="{path.name}"',
+                )
+                msg.attach(part)
+
+        # Send via SMTP
+        context = ssl.create_default_context()
+
+        if settings.SMTP_PORT == 465:
+            # SSL connection
+            with smtplib.SMTP_SSL(settings.SMTP_HOST, settings.SMTP_PORT, context=context) as server:
+                if settings.SMTP_USER and settings.SMTP_PASSWORD:
+                    server.login(settings.SMTP_USER, settings.SMTP_PASSWORD)
+                server.sendmail(settings.SMTP_FROM, to, msg.as_string())
+        else:
+            # STARTTLS connection (port 587 or 25)
+            with smtplib.SMTP(settings.SMTP_HOST, settings.SMTP_PORT) as server:
+                server.ehlo()
+                if settings.SMTP_PORT == 587:
+                    server.starttls(context=context)
+                    server.ehlo()
+                if settings.SMTP_USER and settings.SMTP_PASSWORD:
+                    server.login(settings.SMTP_USER, settings.SMTP_PASSWORD)
+                server.sendmail(settings.SMTP_FROM, to, msg.as_string())
+
+        logger.info(f"Email sent successfully to {to}, subject: {subject}")
+        return True
+
+    except smtplib.SMTPException as e:
+        logger.error(f"SMTP error sending email to {to}: {e}")
+        return False
+    except Exception as e:
+        logger.error(f"Unexpected error sending email to {to}: {e}")
+        return False
diff --git a/backend/app/services/report_scheduler.py b/backend/app/services/report_scheduler.py
new file mode 100644
index 0000000..f286ace
--- /dev/null
+++ b/backend/app/services/report_scheduler.py
@@ -0,0 +1,192 @@
+"""报表定时调度服务 - Schedule report tasks via APScheduler and send results by email."""
+import logging
+from datetime import date, timedelta, datetime, timezone
+
+from apscheduler.schedulers.asyncio import AsyncIOScheduler
+from apscheduler.triggers.cron import CronTrigger
+from sqlalchemy import select
+
+from app.core.database import async_session
+from app.models.report import ReportTask, ReportTemplate
+from app.services.report_generator import ReportGenerator
+from app.services.email_service import send_email
+
+logger = logging.getLogger("report_scheduler")
+
+_scheduler: AsyncIOScheduler | None = None
+
+
+def _parse_cron(cron_expr: str) -> dict:
+    """Parse a 5-field cron expression into APScheduler CronTrigger kwargs."""
+    parts = cron_expr.strip().split()
+    if len(parts) != 5:
+        raise ValueError(f"Invalid cron expression (need 5 fields): {cron_expr}")
+    return {
+        "minute": parts[0],
+        "hour": parts[1],
+        "day": parts[2],
+        "month": parts[3],
+        "day_of_week": parts[4],
+    }
+
+
+async def _run_report_task(task_id: int):
+    """Execute a single report task: generate the report and email it to recipients."""
+    logger.info(f"Running scheduled report task id={task_id}")
+
+    async with async_session() as session:
+        # Load task
+        task_result = await session.execute(
+            select(ReportTask).where(ReportTask.id == task_id)
+        )
+        task = task_result.scalar_one_or_none()
+        if not task:
+            logger.warning(f"Report task id={task_id} not found, skipping.")
+            return
+        if not task.is_active:
+            logger.info(f"Report task id={task_id} is inactive, skipping.")
+            return
+
+        # Update status
+        task.status = "running"
+        task.last_run = datetime.now(timezone.utc)
+        await session.flush()
+
+        # Load template to determine report type
+        tmpl_result = await session.execute(
+            select(ReportTemplate).where(ReportTemplate.id == task.template_id)
+        )
+        template = tmpl_result.scalar_one_or_none()
+        if not template:
+            logger.error(f"Template id={task.template_id} not found for task id={task_id}")
+            task.status = "failed"
+            await session.commit()
+            return
+
+        try:
+            generator = ReportGenerator(session)
+            today = date.today()
+            export_format = task.export_format or "xlsx"
+
+            # Choose generation method based on template report_type
+            if template.report_type == "daily":
+                yesterday = today - timedelta(days=1)
+                filepath = await generator.generate_energy_daily_report(
+                    start_date=yesterday, end_date=yesterday, export_format=export_format
+                )
+            elif template.report_type == "monthly":
+                # Generate for previous month
+                first_of_month = today.replace(day=1)
+                last_month_end = first_of_month - timedelta(days=1)
+                last_month_start = last_month_end.replace(day=1)
+                filepath = await generator.generate_monthly_summary(
+                    month=last_month_start.month,
+                    year=last_month_start.year,
+                    export_format=export_format,
+                )
+            elif template.report_type == "custom" and "device" in template.name.lower():
+                filepath = await generator.generate_device_status_report(
+                    export_format=export_format
+                )
+            else:
+                # Default: daily report for yesterday
+                yesterday = today - timedelta(days=1)
+                filepath = await generator.generate_energy_daily_report(
+                    start_date=yesterday, end_date=yesterday, export_format=export_format
+                )
+
+            task.file_path = filepath
+            task.status = "completed"
+            logger.info(f"Report task id={task_id} completed: {filepath}")
+
+            # Send email with attachment if recipients configured
+            recipients = task.recipients or []
+            if isinstance(recipients, list) and recipients:
+                report_name = task.name or template.name
+                subject = f"{report_name} - 天普EMS自动报表"
+                body_html = f"""
+                <div style="font-family: 'Microsoft YaHei', sans-serif; padding: 20px;">
+                    <h2 style="color: #1a73e8;">天普零碳园区智慧能源管理平台</h2>
+                    <p>您好，</p>
+                    <p>系统已自动生成 <strong>{report_name}</strong>，请查收附件。</p>
+                    <p style="color: #666; font-size: 13px;">
+                        生成时间: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}<br>
+                        报表类型: {template.report_type}<br>
+                        格式: {export_format.upper()}
+                    </p>
+                    <hr style="border: none; border-top: 1px solid #e8e8e8; margin: 20px 0;">
+                    <p style="font-size: 12px; color: #999;">此为系统自动发送，请勿回复。</p>
+                </div>
+                """
+                await send_email(
+                    to=recipients,
+                    subject=subject,
+                    body_html=body_html,
+                    attachments=[filepath],
+                )
+
+        except Exception as e:
+            logger.error(f"Report task id={task_id} failed: {e}", exc_info=True)
+            task.status = "failed"
+
+        await session.commit()
+
+
+async def _load_and_schedule_tasks():
+    """Load all active report tasks with schedules and register them with APScheduler."""
+    global _scheduler
+    if not _scheduler:
+        return
+
+    async with async_session() as session:
+        result = await session.execute(
+            select(ReportTask).where(
+                ReportTask.is_active == True,
+                ReportTask.schedule != None,
+                ReportTask.schedule != "",
+            )
+        )
+        tasks = result.scalars().all()
+
+    for task in tasks:
+        try:
+            cron_kwargs = _parse_cron(task.schedule)
+            _scheduler.add_job(
+                _run_report_task,
+                CronTrigger(**cron_kwargs),
+                args=[task.id],
+                id=f"report_task_{task.id}",
+                replace_existing=True,
+                misfire_grace_time=3600,
+            )
+            logger.info(
+                f"Scheduled report task id={task.id} name='{task.name}' "
+                f"cron='{task.schedule}'"
+            )
+        except Exception as e:
+            logger.error(f"Failed to schedule report task id={task.id}: {e}")
+
+    logger.info(f"Report scheduler loaded {len(tasks)} task(s).")
+
+
+async def start_scheduler():
+    """Start the APScheduler-based report scheduler."""
+    global _scheduler
+    if _scheduler and _scheduler.running:
+        logger.warning("Report scheduler is already running.")
+        return
+
+    _scheduler = AsyncIOScheduler(timezone="Asia/Shanghai")
+    _scheduler.start()
+    logger.info("Report scheduler started.")
+
+    await _load_and_schedule_tasks()
+
+
+async def stop_scheduler():
+    """Stop the report scheduler gracefully."""
+    global _scheduler
+    if _scheduler and _scheduler.running:
+        _scheduler.shutdown(wait=False)
+        logger.info("Report scheduler stopped.")
+    _scheduler = None
diff --git a/backend/app/templates/alarm_email.html b/backend/app/templates/alarm_email.html
new file mode 100644
index 0000000..e2da3e0
--- /dev/null
+++ b/backend/app/templates/alarm_email.html
@@ -0,0 +1,98 @@
+<!DOCTYPE html>
+<html lang="zh-CN">
+<head>
+<meta charset="UTF-8">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
+<body style="margin:0; padding:0; background-color:#f4f5f7; font-family: 'Microsoft YaHei', 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;">
+<table width="100%" cellpadding="0" cellspacing="0" style="background-color:#f4f5f7; padding:20px 0;">
+<tr>
+<td align="center">
+<table width="600" cellpadding="0" cellspacing="0" style="background-color:#ffffff; border-radius:8px; overflow:hidden; box-shadow:0 2px 8px rgba(0,0,0,0.08);">
+
+  <!-- Header -->
+  <tr>
+    <td style="background: linear-gradient(135deg, #1a73e8, #0d47a1); padding:24px 32px; text-align:center;">
+      <div style="font-size:12px; color:rgba(255,255,255,0.8); margin-bottom:4px;">TIANPU EMS</div>
+      <div style="font-size:20px; font-weight:bold; color:#ffffff; letter-spacing:1px;">天普零碳园区智慧能源管理平台</div>
+    </td>
+  </tr>
+
+  <!-- Alert Banner -->
+  <tr>
+    <td style="padding:0;">
+      <table width="100%" cellpadding="0" cellspacing="0">
+        <tr>
+          <td style="background-color:{severity_bg_color}; padding:16px 32px; text-align:center;">
+            <span style="display:inline-block; background-color:{severity_badge_color}; color:#ffffff; font-size:13px; font-weight:bold; padding:4px 16px; border-radius:12px; letter-spacing:1px;">{severity_label}</span>
+            <div style="color:{severity_text_color}; font-size:16px; font-weight:bold; margin-top:8px;">{title}</div>
+          </td>
+        </tr>
+      </table>
+    </td>
+  </tr>
+
+  <!-- Alarm Details -->
+  <tr>
+    <td style="padding:24px 32px;">
+      <table width="100%" cellpadding="0" cellspacing="0" style="border:1px solid #e8e8e8; border-radius:6px; overflow:hidden;">
+        <tr>
+          <td style="background-color:#fafafa; padding:10px 16px; font-size:13px; color:#666; width:120px; border-bottom:1px solid #e8e8e8;">设备名称</td>
+          <td style="padding:10px 16px; font-size:14px; color:#333; border-bottom:1px solid #e8e8e8;">{device_name}</td>
+        </tr>
+        <tr>
+          <td style="background-color:#fafafa; padding:10px 16px; font-size:13px; color:#666; border-bottom:1px solid #e8e8e8;">设备编号</td>
+          <td style="padding:10px 16px; font-size:14px; color:#333; border-bottom:1px solid #e8e8e8;">{device_code}</td>
+        </tr>
+        <tr>
+          <td style="background-color:#fafafa; padding:10px 16px; font-size:13px; color:#666; border-bottom:1px solid #e8e8e8;">监控指标</td>
+          <td style="padding:10px 16px; font-size:14px; color:#333; border-bottom:1px solid #e8e8e8;">{data_type}</td>
+        </tr>
+        <tr>
+          <td style="background-color:#fafafa; padding:10px 16px; font-size:13px; color:#666; border-bottom:1px solid #e8e8e8;">当前值</td>
+          <td style="padding:10px 16px; font-size:14px; color:{severity_badge_color}; font-weight:bold; border-bottom:1px solid #e8e8e8;">{current_value}</td>
+        </tr>
+        <tr>
+          <td style="background-color:#fafafa; padding:10px 16px; font-size:13px; color:#666; border-bottom:1px solid #e8e8e8;">告警阈值</td>
+          <td style="padding:10px 16px; font-size:14px; color:#333; border-bottom:1px solid #e8e8e8;">{threshold_str}</td>
+        </tr>
+        <tr>
+          <td style="background-color:#fafafa; padding:10px 16px; font-size:13px; color:#666;">触发时间</td>
+          <td style="padding:10px 16px; font-size:14px; color:#333;">{triggered_at}</td>
+        </tr>
+      </table>
+    </td>
+  </tr>
+
+  <!-- Description -->
+  <tr>
+    <td style="padding:0 32px 24px;">
+      <div style="background-color:#fff8e1; border-left:4px solid #ffa000; padding:12px 16px; border-radius:0 4px 4px 0; font-size:13px; color:#795548;">
+        {description}
+      </div>
+    </td>
+  </tr>
+
+  <!-- Action Button -->
+  <tr>
+    <td style="padding:0 32px 24px; text-align:center;">
+      <a href="{platform_url}/alarms" style="display:inline-block; background-color:#1a73e8; color:#ffffff; text-decoration:none; padding:12px 32px; border-radius:6px; font-size:14px; font-weight:bold;">查看告警详情</a>
+    </td>
+  </tr>
+
+  <!-- Footer -->
+  <tr>
+    <td style="background-color:#f8f9fa; padding:16px 32px; border-top:1px solid #e8e8e8;">
+      <div style="font-size:12px; color:#999; text-align:center; line-height:1.6;">
+        此为系统自动发送，请勿回复。<br>
+        天普零碳园区智慧能源管理平台 &copy; 2026
+      </div>
+    </td>
+  </tr>
+
+</table>
+</td>
+</tr>
+</table>
+</body>
+</html>
diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index f82a37b..e26b189 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -18,8 +18,10 @@
         "dayjs": "^1.11.20",
         "echarts": "^6.0.0",
         "echarts-for-react": "^3.0.6",
+        "i18next": "^24.2.2",
         "react": "^19.2.4",
         "react-dom": "^19.2.4",
+        "react-i18next": "^15.4.1",
         "react-router-dom": "^6.30.3",
         "three": "^0.183.2"
       },
@@ -1069,9 +1071,9 @@
       }
     },
     "node_modules/@emnapi/wasi-threads": {
-      "version": "1.2.0",
-      "resolved": "https://registry.npmjs.org/@emnapi/wasi-threads/-/wasi-threads-1.2.0.tgz",
-      "integrity": "sha512-N10dEJNSsUx41Z6pZsXU8FjPjpBEplgH24sfkmITrBED1/U2Esum9F3lfLrMjKHHjmi557zQn7kR9R+XWXu5Rg==",
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/@emnapi/wasi-threads/-/wasi-threads-1.2.1.tgz",
+      "integrity": "sha512-uTII7OYF+/Mes/MrcIOYp5yOtSMLBWSIoLPpcgwipoiKbli6k322tcoFsxoIIxPDqW01SQGAgko4EzZi2BNv2w==",
       "dev": true,
       "license": "MIT",
       "optional": true,
@@ -3628,6 +3630,47 @@
       "integrity": "sha512-E3a5VwgXimGHwpRGV+WxRTKeSp2DW5DI5MWv34ulL3t5UNmyJWCQ1KmLEHbYzcfThfXG8amBL+fCYPneGHC4VA==",
       "license": "Apache-2.0"
     },
+    "node_modules/html-parse-stringify": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/html-parse-stringify/-/html-parse-stringify-3.0.1.tgz",
+      "integrity": "sha512-KknJ50kTInJ7qIScF3jeaFRpMpE8/lfiTdzf/twXyPBLAGrLRTmkz3AdTnKeh40X8k9L2fdYwEp/42WGXIRGcg==",
+      "license": "MIT",
+      "dependencies": {
+        "void-elements": "3.1.0"
+      }
+    },
+    "node_modules/i18next": {
+      "version": "24.2.3",
+      "resolved": "https://registry.npmjs.org/i18next/-/i18next-24.2.3.tgz",
+      "integrity": "sha512-lfbf80OzkocvX7nmZtu7nSTNbrTYR52sLWxPtlXX1zAhVw8WEnFk4puUkCR4B1dNQwbSpEHHHemcZu//7EcB7A==",
+      "funding": [
+        {
+          "type": "individual",
+          "url": "https://locize.com"
+        },
+        {
+          "type": "individual",
+          "url": "https://locize.com/i18next.html"
+        },
+        {
+          "type": "individual",
+          "url": "https://www.i18next.com/how-to/faq#i18next-is-awesome.-how-can-i-support-the-project"
+        }
+      ],
+      "license": "MIT",
+      "peer": true,
+      "dependencies": {
+        "@babel/runtime": "^7.26.10"
+      },
+      "peerDependencies": {
+        "typescript": "^5"
+      },
+      "peerDependenciesMeta": {
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/ieee754": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/ieee754/-/ieee754-1.2.1.tgz",
@@ -5140,6 +5183,32 @@
         "react": "^19.2.4"
       }
     },
+    "node_modules/react-i18next": {
+      "version": "15.7.4",
+      "resolved": "https://registry.npmjs.org/react-i18next/-/react-i18next-15.7.4.tgz",
+      "integrity": "sha512-nyU8iKNrI5uDJch0z9+Y5XEr34b0wkyYj3Rp+tfbahxtlswxSCjcUL9H0nqXo9IR3/t5Y5PKIA3fx3MfUyR9Xw==",
+      "license": "MIT",
+      "dependencies": {
+        "@babel/runtime": "^7.27.6",
+        "html-parse-stringify": "^3.0.1"
+      },
+      "peerDependencies": {
+        "i18next": ">= 23.4.0",
+        "react": ">= 16.8.0",
+        "typescript": "^5"
+      },
+      "peerDependenciesMeta": {
+        "react-dom": {
+          "optional": true
+        },
+        "react-native": {
+          "optional": true
+        },
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/react-is": {
       "version": "18.3.1",
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-18.3.1.tgz",
@@ -5617,7 +5686,7 @@
       "version": "5.9.3",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
       "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
-      "dev": true,
+      "devOptional": true,
       "license": "Apache-2.0",
       "peer": true,
       "bin": {
@@ -5797,6 +5866,15 @@
         }
       }
     },
+    "node_modules/void-elements": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/void-elements/-/void-elements-3.1.0.tgz",
+      "integrity": "sha512-Dhxzh5HZuiHQhbvTW9AMetFfBHDMYpo23Uo9btPXgdYP+3T5S+p+jgNy7spra+veYhBP2dCSgxR/i2Y02h5/6w==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
     "node_modules/warning": {
       "version": "4.0.3",
       "resolved": "https://registry.npmjs.org/warning/-/warning-4.0.3.tgz",
diff --git a/frontend/package.json b/frontend/package.json
index b83f659..1a97f80 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -20,6 +20,8 @@
     "dayjs": "^1.11.20",
     "echarts": "^6.0.0",
     "echarts-for-react": "^3.0.6",
+    "i18next": "^24.2.2",
+    "react-i18next": "^15.4.1",
     "react": "^19.2.4",
     "react-dom": "^19.2.4",
     "react-router-dom": "^6.30.3",
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 2755d6a..d89fa5b 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1,6 +1,10 @@
 import { BrowserRouter, Routes, Route, Navigate } from 'react-router-dom';
-import { ConfigProvider } from 'antd';
+import { ConfigProvider, theme } from 'antd';
 import zhCN from 'antd/locale/zh_CN';
+import enUS from 'antd/locale/en_US';
+import { useTranslation } from 'react-i18next';
+import { ThemeProvider, useTheme } from './contexts/ThemeContext';
+import './i18n';
 import MainLayout from './layouts/MainLayout';
 import LoginPage from './pages/Login';
 import Dashboard from './pages/Dashboard';
@@ -10,6 +14,7 @@ import Alarms from './pages/Alarms';
 import Carbon from './pages/Carbon';
 import Reports from './pages/Reports';
 import Devices from './pages/Devices';
+import DeviceDetail from './pages/DeviceDetail';
 import SystemManagement from './pages/System';
 import BigScreen from './pages/BigScreen';
 import BigScreen3D from './pages/BigScreen3D';
@@ -20,11 +25,18 @@ function ProtectedRoute({ children }: { children: React.ReactNode }) {
   return <>{children}</>;
 }
 
-export default function App() {
+function AppContent() {
+  const { darkMode } = useTheme();
+  const { i18n } = useTranslation();
+
   return (
-    <ConfigProvider locale={zhCN} theme={{
-      token: { colorPrimary: '#1890ff', borderRadius: 6 },
-    }}>
+    <ConfigProvider
+      locale={i18n.language === 'en' ? enUS : zhCN}
+      theme={{
+        algorithm: darkMode ? theme.darkAlgorithm : theme.defaultAlgorithm,
+        token: { colorPrimary: '#1890ff', borderRadius: 6 },
+      }}
+    >
       <BrowserRouter>
         <Routes>
           <Route path="/login" element={<LoginPage />} />
@@ -34,6 +46,7 @@ export default function App() {
             <Route index element={<Dashboard />} />
             <Route path="monitoring" element={<Monitoring />} />
             <Route path="devices" element={<Devices />} />
+            <Route path="devices/:id" element={<DeviceDetail />} />
             <Route path="analysis" element={<Analysis />} />
             <Route path="alarms" element={<Alarms />} />
             <Route path="carbon" element={<Carbon />} />
@@ -45,3 +58,11 @@ export default function App() {
     </ConfigProvider>
   );
 }
+
+export default function App() {
+  return (
+    <ThemeProvider>
+      <AppContent />
+    </ThemeProvider>
+  );
+}
diff --git a/frontend/src/contexts/ThemeContext.tsx b/frontend/src/contexts/ThemeContext.tsx
new file mode 100644
index 0000000..f20eb9e
--- /dev/null
+++ b/frontend/src/contexts/ThemeContext.tsx
@@ -0,0 +1,33 @@
+import { createContext, useContext, useState, useEffect, type ReactNode } from 'react';
+
+interface ThemeContextType {
+  darkMode: boolean;
+  toggleDarkMode: () => void;
+}
+
+const ThemeContext = createContext<ThemeContextType>({
+  darkMode: false,
+  toggleDarkMode: () => {},
+});
+
+export function ThemeProvider({ children }: { children: ReactNode }) {
+  const [darkMode, setDarkMode] = useState(() => {
+    const saved = localStorage.getItem('tianpu-dark-mode');
+    return saved === 'true';
+  });
+
+  useEffect(() => {
+    localStorage.setItem('tianpu-dark-mode', String(darkMode));
+    document.documentElement.setAttribute('data-theme', darkMode ? 'dark' : 'light');
+  }, [darkMode]);
+
+  const toggleDarkMode = () => setDarkMode(prev => !prev);
+
+  return (
+    <ThemeContext.Provider value={{ darkMode, toggleDarkMode }}>
+      {children}
+    </ThemeContext.Provider>
+  );
+}
+
+export const useTheme = () => useContext(ThemeContext);
diff --git a/frontend/src/i18n/index.ts b/frontend/src/i18n/index.ts
new file mode 100644
index 0000000..99508f2
--- /dev/null
+++ b/frontend/src/i18n/index.ts
@@ -0,0 +1,18 @@
+import i18n from 'i18next';
+import { initReactI18next } from 'react-i18next';
+import zh from './locales/zh.json';
+import en from './locales/en.json';
+
+i18n.use(initReactI18next).init({
+  resources: {
+    zh: { translation: zh },
+    en: { translation: en },
+  },
+  lng: localStorage.getItem('tianpu-lang') || 'zh',
+  fallbackLng: 'zh',
+  interpolation: {
+    escapeValue: false,
+  },
+});
+
+export default i18n;
diff --git a/frontend/src/i18n/locales/en.json b/frontend/src/i18n/locales/en.json
new file mode 100644
index 0000000..2fdc79a
--- /dev/null
+++ b/frontend/src/i18n/locales/en.json
@@ -0,0 +1,58 @@
+{
+  "menu": {
+    "dashboard": "Energy Overview",
+    "monitoring": "Real-time Monitoring",
+    "devices": "Device Management",
+    "analysis": "Energy Analysis",
+    "alarms": "Alarm Management",
+    "carbon": "Carbon Management",
+    "reports": "Reports",
+    "bigscreen": "Visual Dashboard",
+    "bigscreen2d": "2D Energy Screen",
+    "bigscreen3d": "3D Park Screen",
+    "system": "System Management",
+    "users": "User Management",
+    "roles": "Roles & Permissions",
+    "settings": "System Settings",
+    "audit": "Audit Log"
+  },
+  "header": {
+    "alarmNotification": "Alarm Notifications",
+    "activeAlarms": "active",
+    "noActiveAlarms": "No active alarms",
+    "viewAllAlarms": "View all alarms",
+    "profile": "Profile",
+    "logout": "Sign Out",
+    "brandName": "Tianpu EMS"
+  },
+  "common": {
+    "save": "Save",
+    "cancel": "Cancel",
+    "confirm": "Confirm",
+    "delete": "Delete",
+    "edit": "Edit",
+    "add": "Add",
+    "search": "Search",
+    "reset": "Reset",
+    "export": "Export",
+    "import": "Import",
+    "loading": "Loading",
+    "success": "Success",
+    "error": "Error",
+    "noData": "No data"
+  },
+  "analysis": {
+    "dataComparison": "Data Comparison",
+    "energyTrend": "Energy Trend",
+    "dailySummary": "Daily Energy Summary",
+    "period1": "Period 1",
+    "period2": "Period 2",
+    "totalConsumption": "Total Consumption",
+    "peakPower": "Peak Power",
+    "avgLoad": "Average Load",
+    "carbonEmission": "Carbon Emission",
+    "change": "Change",
+    "compare": "Compare",
+    "selectDateRange": "Select date range"
+  }
+}
diff --git a/frontend/src/i18n/locales/zh.json b/frontend/src/i18n/locales/zh.json
new file mode 100644
index 0000000..5a04165
--- /dev/null
+++ b/frontend/src/i18n/locales/zh.json
@@ -0,0 +1,58 @@
+{
+  "menu": {
+    "dashboard": "能源总览",
+    "monitoring": "实时监控",
+    "devices": "设备管理",
+    "analysis": "能耗分析",
+    "alarms": "告警管理",
+    "carbon": "碳排放管理",
+    "reports": "报表管理",
+    "bigscreen": "可视化大屏",
+    "bigscreen2d": "2D 能源大屏",
+    "bigscreen3d": "3D 园区大屏",
+    "system": "系统管理",
+    "users": "用户管理",
+    "roles": "角色权限",
+    "settings": "系统设置",
+    "audit": "审计日志"
+  },
+  "header": {
+    "alarmNotification": "告警通知",
+    "activeAlarms": "条活跃",
+    "noActiveAlarms": "暂无活跃告警",
+    "viewAllAlarms": "查看全部告警",
+    "profile": "个人信息",
+    "logout": "退出登录",
+    "brandName": "天普EMS"
+  },
+  "common": {
+    "save": "保存",
+    "cancel": "取消",
+    "confirm": "确认",
+    "delete": "删除",
+    "edit": "编辑",
+    "add": "新增",
+    "search": "搜索",
+    "reset": "重置",
+    "export": "导出",
+    "import": "导入",
+    "loading": "加载中",
+    "success": "操作成功",
+    "error": "操作失败",
+    "noData": "暂无数据"
+  },
+  "analysis": {
+    "dataComparison": "数据对比",
+    "energyTrend": "能耗趋势",
+    "dailySummary": "每日能耗汇总",
+    "period1": "时段一",
+    "period2": "时段二",
+    "totalConsumption": "总用电量",
+    "peakPower": "峰值功率",
+    "avgLoad": "平均负荷",
+    "carbonEmission": "碳排放",
+    "change": "变化",
+    "compare": "对比",
+    "selectDateRange": "选择日期范围"
+  }
+}
diff --git a/frontend/src/index.css b/frontend/src/index.css
index 683bf51..ccd2059 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -45,6 +45,30 @@ body {
   }
 }
 
+/* ============================================
+   Dark mode support
+   ============================================ */
+
+[data-theme='dark'] body {
+  background: #141414;
+  color: rgba(255, 255, 255, 0.85);
+}
+
+[data-theme='dark'] .ant-layout-content {
+  background: #1f1f1f !important;
+}
+
+[data-theme='dark'] .ant-card {
+  background: #1f1f1f;
+  border-color: #303030;
+}
+
+[data-theme='dark'] .ant-table {
+  background: #1f1f1f;
+}
+
+/* BigScreen pages are already dark themed, no overrides needed */
+
 /* Mobile: tighter spacing */
 @media (max-width: 375px) {
   .ant-layout-header {
diff --git a/frontend/src/layouts/MainLayout.tsx b/frontend/src/layouts/MainLayout.tsx
index c02b143..60d6aae 100644
--- a/frontend/src/layouts/MainLayout.tsx
+++ b/frontend/src/layouts/MainLayout.tsx
@@ -1,42 +1,22 @@
 import { useState, useEffect, useCallback } from 'react';
-import { Layout, Menu, Avatar, Dropdown, Typography, Badge, Popover, List, Tag, Empty } from 'antd';
+import { Layout, Menu, Avatar, Dropdown, Typography, Badge, Popover, List, Tag, Empty, Select } from 'antd';
 import {
   DashboardOutlined, MonitorOutlined, BarChartOutlined, AlertOutlined,
   FileTextOutlined, CloudOutlined, SettingOutlined, UserOutlined,
   MenuFoldOutlined, MenuUnfoldOutlined, LogoutOutlined, BellOutlined,
   ThunderboltOutlined, AppstoreOutlined, WarningOutlined, CloseCircleOutlined,
   InfoCircleOutlined, FundProjectionScreenOutlined, GlobalOutlined,
+  BulbOutlined, BulbFilled,
 } from '@ant-design/icons';
 import { Outlet, useNavigate, useLocation } from 'react-router-dom';
+import { useTranslation } from 'react-i18next';
 import { getUser, removeToken } from '../utils/auth';
 import { getAlarmStats, getAlarmEvents } from '../services/api';
+import { useTheme } from '../contexts/ThemeContext';
 
 const { Header, Sider, Content } = Layout;
 const { Text } = Typography;
 
-const menuItems = [
-  { key: '/', icon: <DashboardOutlined />, label: '能源总览' },
-  { key: '/monitoring', icon: <MonitorOutlined />, label: '实时监控' },
-  { key: '/devices', icon: <AppstoreOutlined />, label: '设备管理' },
-  { key: '/analysis', icon: <BarChartOutlined />, label: '能耗分析' },
-  { key: '/alarms', icon: <AlertOutlined />, label: '告警管理' },
-  { key: '/carbon', icon: <CloudOutlined />, label: '碳排放管理' },
-  { key: '/reports', icon: <FileTextOutlined />, label: '报表管理' },
-  { key: 'bigscreen-group', icon: <FundProjectionScreenOutlined />, label: '可视化大屏',
-    children: [
-      { key: '/bigscreen', icon: <FundProjectionScreenOutlined />, label: '2D 能源大屏' },
-      { key: '/bigscreen-3d', icon: <GlobalOutlined />, label: '3D 园区大屏' },
-    ],
-  },
-  { key: '/system', icon: <SettingOutlined />, label: '系统管理',
-    children: [
-      { key: '/system/users', label: '用户管理' },
-      { key: '/system/roles', label: '角色权限' },
-      { key: '/system/settings', label: '系统设置' },
-    ],
-  },
-];
-
 const SEVERITY_CONFIG: Record<string, { icon: React.ReactNode; color: string }> = {
   critical: { icon: <CloseCircleOutlined style={{ color: '#f5222d' }} />, color: 'red' },
   warning: { icon: <WarningOutlined style={{ color: '#faad14' }} />, color: 'orange' },
@@ -50,6 +30,32 @@ export default function MainLayout() {
   const navigate = useNavigate();
   const location = useLocation();
   const user = getUser();
+  const { darkMode, toggleDarkMode } = useTheme();
+  const { t, i18n } = useTranslation();
+
+  const menuItems = [
+    { key: '/', icon: <DashboardOutlined />, label: t('menu.dashboard') },
+    { key: '/monitoring', icon: <MonitorOutlined />, label: t('menu.monitoring') },
+    { key: '/devices', icon: <AppstoreOutlined />, label: t('menu.devices') },
+    { key: '/analysis', icon: <BarChartOutlined />, label: t('menu.analysis') },
+    { key: '/alarms', icon: <AlertOutlined />, label: t('menu.alarms') },
+    { key: '/carbon', icon: <CloudOutlined />, label: t('menu.carbon') },
+    { key: '/reports', icon: <FileTextOutlined />, label: t('menu.reports') },
+    { key: 'bigscreen-group', icon: <FundProjectionScreenOutlined />, label: t('menu.bigscreen'),
+      children: [
+        { key: '/bigscreen', icon: <FundProjectionScreenOutlined />, label: t('menu.bigscreen2d') },
+        { key: '/bigscreen-3d', icon: <GlobalOutlined />, label: t('menu.bigscreen3d') },
+      ],
+    },
+    { key: '/system', icon: <SettingOutlined />, label: t('menu.system'),
+      children: [
+        { key: '/system/users', label: t('menu.users') },
+        { key: '/system/roles', label: t('menu.roles') },
+        { key: '/system/settings', label: t('menu.settings') },
+        { key: '/system/audit', label: t('menu.audit', '审计日志') },
+      ],
+    },
+  ];
 
   const fetchAlarms = useCallback(async () => {
     try {
@@ -57,7 +63,6 @@ export default function MainLayout() {
         getAlarmStats(),
         getAlarmEvents({ status: 'active', page_size: 5 }),
       ]);
-      // Stats shape: { severity: { status: count } } — sum all "active" counts
       const statsData = (stats as any) || {};
       let activeTotal = 0;
       for (const severity of Object.values(statsData)) {
@@ -85,24 +90,29 @@ export default function MainLayout() {
     navigate('/login');
   };
 
+  const handleLanguageChange = (lang: string) => {
+    i18n.changeLanguage(lang);
+    localStorage.setItem('tianpu-lang', lang);
+  };
+
   const userMenu = {
     items: [
-      { key: 'profile', icon: <UserOutlined />, label: '个人信息' },
+      { key: 'profile', icon: <UserOutlined />, label: t('header.profile') },
       { type: 'divider' as const },
-      { key: 'logout', icon: <LogoutOutlined />, label: '退出登录', onClick: handleLogout },
+      { key: 'logout', icon: <LogoutOutlined />, label: t('header.logout'), onClick: handleLogout },
     ],
   };
 
   return (
     <Layout style={{ minHeight: '100vh' }}>
       <Sider trigger={null} collapsible collapsed={collapsed} width={220}
-        style={{ background: '#001529' }}>
+        style={{ background: darkMode ? '#141414' : '#001529' }}>
         <div style={{
           height: 64, display: 'flex', alignItems: 'center', justifyContent: 'center',
           borderBottom: '1px solid rgba(255,255,255,0.1)',
         }}>
           <ThunderboltOutlined style={{ fontSize: 24, color: '#1890ff', marginRight: collapsed ? 0 : 8 }} />
-          {!collapsed && <Text strong style={{ color: '#fff', fontSize: 16 }}>天普EMS</Text>}
+          {!collapsed && <Text strong style={{ color: '#fff', fontSize: 16 }}>{t('header.brandName')}</Text>}
         </div>
         <Menu
           theme="dark" mode="inline"
@@ -120,9 +130,9 @@ export default function MainLayout() {
       </Sider>
       <Layout>
         <Header style={{
-          padding: '0 24px', background: '#fff', display: 'flex',
+          padding: '0 24px', background: darkMode ? '#141414' : '#fff', display: 'flex',
           alignItems: 'center', justifyContent: 'space-between',
-          boxShadow: '0 1px 4px rgba(0,0,0,0.08)',
+          boxShadow: darkMode ? '0 1px 4px rgba(0,0,0,0.3)' : '0 1px 4px rgba(0,0,0,0.08)',
         }}>
           <div style={{ display: 'flex', alignItems: 'center', cursor: 'pointer' }}
             onClick={() => setCollapsed(!collapsed)}>
@@ -130,17 +140,34 @@ export default function MainLayout() {
               <MenuFoldOutlined style={{ fontSize: 18 }} />}
           </div>
           <div style={{ display: 'flex', alignItems: 'center', gap: 16 }}>
+            <Select
+              value={i18n.language}
+              onChange={handleLanguageChange}
+              size="small"
+              style={{ width: 90 }}
+              options={[
+                { label: '中文', value: 'zh' },
+                { label: 'English', value: 'en' },
+              ]}
+            />
+            <div
+              style={{ cursor: 'pointer', fontSize: 18, display: 'flex', alignItems: 'center' }}
+              onClick={toggleDarkMode}
+              title={darkMode ? 'Switch to light mode' : 'Switch to dark mode'}
+            >
+              {darkMode ? <BulbFilled style={{ color: '#faad14' }} /> : <BulbOutlined />}
+            </div>
             <Popover
               trigger="click"
               placement="bottomRight"
               title={<div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
-                <span>告警通知</span>
-                {alarmCount > 0 && <Tag color="red">{alarmCount} 条活跃</Tag>}
+                <span>{t('header.alarmNotification')}</span>
+                {alarmCount > 0 && <Tag color="red">{alarmCount} {t('header.activeAlarms')}</Tag>}
               </div>}
               content={
                 <div style={{ width: 320, maxHeight: 360, overflow: 'auto' }}>
                   {recentAlarms.length === 0 ? (
-                    <Empty image={Empty.PRESENTED_IMAGE_SIMPLE} description="暂无活跃告警" />
+                    <Empty image={Empty.PRESENTED_IMAGE_SIMPLE} description={t('header.noActiveAlarms')} />
                   ) : (
                     <List size="small" dataSource={recentAlarms} renderItem={(alarm: any) => {
                       const sev = SEVERITY_CONFIG[alarm.severity] || SEVERITY_CONFIG.info;
@@ -162,7 +189,7 @@ export default function MainLayout() {
                     }} />
                   )}
                   <div style={{ textAlign: 'center', padding: '8px 0', borderTop: '1px solid #f0f0f0' }}>
-                    <a onClick={() => navigate('/alarms')} style={{ fontSize: 13 }}>查看全部告警</a>
+                    <a onClick={() => navigate('/alarms')} style={{ fontSize: 13 }}>{t('header.viewAllAlarms')}</a>
                   </div>
                 </div>
               }
@@ -179,7 +206,7 @@ export default function MainLayout() {
             </Dropdown>
           </div>
         </Header>
-        <Content style={{ margin: 16, padding: 24, background: '#f5f5f5', minHeight: 280 }}>
+        <Content style={{ margin: 16, padding: 24, background: darkMode ? '#1f1f1f' : '#f5f5f5', minHeight: 280 }}>
           <Outlet />
         </Content>
       </Layout>
diff --git a/frontend/src/pages/Analysis/index.tsx b/frontend/src/pages/Analysis/index.tsx
index a2dd176..dbf12c8 100644
--- a/frontend/src/pages/Analysis/index.tsx
+++ b/frontend/src/pages/Analysis/index.tsx
@@ -1,16 +1,196 @@
 import { useEffect, useState } from 'react';
-import { Card, Row, Col, DatePicker, Select, Statistic, Table, Button, Space, message } from 'antd';
-import { ArrowUpOutlined, ArrowDownOutlined, DownloadOutlined } from '@ant-design/icons';
+import { Card, Row, Col, DatePicker, Select, Statistic, Table, Button, Space, message, Tabs } from 'antd';
+import { ArrowUpOutlined, ArrowDownOutlined, DownloadOutlined, SwapOutlined } from '@ant-design/icons';
 import ReactECharts from 'echarts-for-react';
-import dayjs from 'dayjs';
+import dayjs, { type Dayjs } from 'dayjs';
 import { getEnergyHistory, getEnergyComparison, getEnergyDailySummary, exportEnergyData } from '../../services/api';
 
+const { RangePicker } = DatePicker;
+
+function ComparisonView() {
+  const [range1, setRange1] = useState<[Dayjs, Dayjs]>([
+    dayjs().subtract(30, 'day'), dayjs(),
+  ]);
+  const [range2, setRange2] = useState<[Dayjs, Dayjs]>([
+    dayjs().subtract(60, 'day'), dayjs().subtract(30, 'day'),
+  ]);
+  const [data1, setData1] = useState<any[]>([]);
+  const [data2, setData2] = useState<any[]>([]);
+  const [summary1, setSummary1] = useState<any[]>([]);
+  const [summary2, setSummary2] = useState<any[]>([]);
+  const [comparison, setComparison] = useState<any>(null);
+  const [loading, setLoading] = useState(false);
+
+  const loadComparisonData = async () => {
+    setLoading(true);
+    try {
+      const [hist1, hist2, daily1, daily2, comp] = await Promise.all([
+        getEnergyHistory({
+          data_type: 'power', granularity: 'day',
+          start_time: range1[0].format('YYYY-MM-DD'),
+          end_time: range1[1].format('YYYY-MM-DD'),
+        }),
+        getEnergyHistory({
+          data_type: 'power', granularity: 'day',
+          start_time: range2[0].format('YYYY-MM-DD'),
+          end_time: range2[1].format('YYYY-MM-DD'),
+        }),
+        getEnergyDailySummary({
+          energy_type: 'electricity',
+          start_date: range1[0].format('YYYY-MM-DD'),
+          end_date: range1[1].format('YYYY-MM-DD'),
+        }),
+        getEnergyDailySummary({
+          energy_type: 'electricity',
+          start_date: range2[0].format('YYYY-MM-DD'),
+          end_date: range2[1].format('YYYY-MM-DD'),
+        }),
+        getEnergyComparison({ energy_type: 'electricity', period: 'month' }),
+      ]);
+      setData1(hist1 as any[]);
+      setData2(hist2 as any[]);
+      setSummary1(daily1 as any[]);
+      setSummary2(daily2 as any[]);
+      setComparison(comp);
+    } catch (e) {
+      console.error(e);
+      message.error('加载对比数据失败');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  useEffect(() => {
+    loadComparisonData();
+  }, []);
+
+  const calcMetrics = (summaryData: any[]) => {
+    if (!summaryData || summaryData.length === 0) {
+      return { totalConsumption: 0, peakPower: 0, avgLoad: 0, carbonEmission: 0 };
+    }
+    const totalConsumption = summaryData.reduce((s, d) => s + (d.consumption || 0), 0);
+    const peakPower = Math.max(...summaryData.map(d => d.peak_power || 0));
+    const avgLoad = summaryData.reduce((s, d) => s + (d.avg_power || 0), 0) / summaryData.length;
+    const carbonEmission = summaryData.reduce((s, d) => s + (d.carbon_emission || 0), 0);
+    return { totalConsumption, peakPower, avgLoad, carbonEmission };
+  };
+
+  const m1 = calcMetrics(summary1);
+  const m2 = calcMetrics(summary2);
+
+  const pctChange = (v1: number, v2: number) => {
+    if (v2 === 0) return 0;
+    return ((v1 - v2) / v2) * 100;
+  };
+
+  const comparisonChartOption = {
+    tooltip: { trigger: 'axis' },
+    legend: { data: ['时段一', '时段二'] },
+    grid: { top: 50, right: 40, bottom: 30, left: 60 },
+    xAxis: {
+      type: 'category',
+      data: (data1.length >= data2.length ? data1 : data2).map((_, i) => `Day ${i + 1}`),
+    },
+    yAxis: [
+      { type: 'value', name: 'kW', position: 'left' },
+      { type: 'value', name: 'kW', position: 'right' },
+    ],
+    series: [
+      {
+        name: '时段一',
+        type: 'line',
+        smooth: true,
+        data: data1.map(d => d.avg),
+        lineStyle: { color: '#1890ff' },
+        itemStyle: { color: '#1890ff' },
+        yAxisIndex: 0,
+      },
+      {
+        name: '时段二',
+        type: 'line',
+        smooth: true,
+        data: data2.map(d => d.avg),
+        lineStyle: { color: '#faad14' },
+        itemStyle: { color: '#faad14' },
+        yAxisIndex: 1,
+      },
+    ],
+  };
+
+  const renderMetricCard = (
+    label: string, v1: number, v2: number, unit: string, precision = 1,
+  ) => {
+    const change = pctChange(v1, v2);
+    const isImproved = change < 0; // less consumption = improvement
+    return (
+      <Col xs={24} sm={12} md={6} key={label}>
+        <Card size="small">
+          <div style={{ marginBottom: 8, fontWeight: 500, color: '#666' }}>{label}</div>
+          <Row gutter={16}>
+            <Col span={12}>
+              <div style={{ fontSize: 12, color: '#999' }}>时段一</div>
+              <div style={{ fontSize: 18, fontWeight: 600 }}>{v1.toFixed(precision)}</div>
+              <div style={{ fontSize: 12, color: '#999' }}>{unit}</div>
+            </Col>
+            <Col span={12}>
+              <div style={{ fontSize: 12, color: '#999' }}>时段二</div>
+              <div style={{ fontSize: 18, fontWeight: 600 }}>{v2.toFixed(precision)}</div>
+              <div style={{ fontSize: 12, color: '#999' }}>{unit}</div>
+            </Col>
+          </Row>
+          <div style={{
+            marginTop: 8, fontSize: 13, fontWeight: 500,
+            color: isImproved ? '#52c41a' : change > 0 ? '#f5222d' : '#666',
+          }}>
+            {change > 0 ? <ArrowUpOutlined /> : change < 0 ? <ArrowDownOutlined /> : null}
+            {' '}{Math.abs(change).toFixed(1)}% {isImproved ? '减少' : change > 0 ? '增加' : '持平'}
+          </div>
+        </Card>
+      </Col>
+    );
+  };
+
+  return (
+    <div>
+      <Card size="small" style={{ marginBottom: 16 }}>
+        <Space wrap>
+          <span>时段一:</span>
+          <RangePicker
+            value={range1}
+            onChange={(dates) => dates && setRange1(dates as [Dayjs, Dayjs])}
+          />
+          <span>时段二:</span>
+          <RangePicker
+            value={range2}
+            onChange={(dates) => dates && setRange2(dates as [Dayjs, Dayjs])}
+          />
+          <Button type="primary" icon={<SwapOutlined />} loading={loading} onClick={loadComparisonData}>
+            对比
+          </Button>
+        </Space>
+      </Card>
+
+      <Row gutter={[16, 16]} style={{ marginBottom: 16 }}>
+        {renderMetricCard('总用电量', m1.totalConsumption, m2.totalConsumption, 'kWh')}
+        {renderMetricCard('峰值功率', m1.peakPower, m2.peakPower, 'kW')}
+        {renderMetricCard('平均负荷', m1.avgLoad, m2.avgLoad, 'kW')}
+        {renderMetricCard('碳排放', m1.carbonEmission, m2.carbonEmission, 'kg', 2)}
+      </Row>
+
+      <Card title="能耗趋势对比" size="small">
+        <ReactECharts option={comparisonChartOption} style={{ height: 350 }} />
+      </Card>
+    </div>
+  );
+}
+
 export default function Analysis() {
   const [historyData, setHistoryData] = useState<any[]>([]);
   const [comparison, setComparison] = useState<any>(null);
   const [dailySummary, setDailySummary] = useState<any[]>([]);
   const [granularity, setGranularity] = useState('hour');
   const [exporting, setExporting] = useState(false);
+  const [activeTab, setActiveTab] = useState('overview');
 
   useEffect(() => {
     loadData();
@@ -76,7 +256,7 @@ export default function Analysis() {
     { title: '碳排放(kg)', dataIndex: 'carbon_emission', render: (v: number) => v?.toFixed(2) },
   ];
 
-  return (
+  const overviewContent = (
     <div>
       <Row justify="end" style={{ marginBottom: 16 }}>
         <Col>
@@ -130,4 +310,17 @@ export default function Analysis() {
       </Card>
     </div>
   );
+
+  return (
+    <div>
+      <Tabs
+        activeKey={activeTab}
+        onChange={setActiveTab}
+        items={[
+          { key: 'overview', label: '能耗概览', children: overviewContent },
+          { key: 'comparison', label: '数据对比', children: <ComparisonView /> },
+        ]}
+      />
+    </div>
+  );
 }
diff --git a/frontend/src/pages/DeviceDetail/index.tsx b/frontend/src/pages/DeviceDetail/index.tsx
new file mode 100644
index 0000000..83cc59e
--- /dev/null
+++ b/frontend/src/pages/DeviceDetail/index.tsx
@@ -0,0 +1,490 @@
+import { useEffect, useState, useCallback } from 'react';
+import { useParams, useNavigate } from 'react-router-dom';
+import {
+  Card, Tabs, Tag, Button, Statistic, Row, Col, Table, Descriptions, Select,
+  DatePicker, Space, Badge, Spin, message, Empty,
+} from 'antd';
+import {
+  ArrowLeftOutlined, ReloadOutlined, ThunderboltOutlined,
+  DashboardOutlined, FireOutlined, ExperimentOutlined,
+} from '@ant-design/icons';
+import ReactECharts from 'echarts-for-react';
+import dayjs from 'dayjs';
+import { getDevice, getDeviceRealtime, getEnergyHistory, getAlarmEvents } from '../../services/api';
+import { getDevicePhoto } from '../../utils/devicePhoto';
+
+const { RangePicker } = DatePicker;
+
+const statusMap: Record<string, { color: string; text: string }> = {
+  online: { color: 'green', text: '在线' },
+  offline: { color: 'default', text: '离线' },
+  alarm: { color: 'red', text: '告警' },
+  maintenance: { color: 'orange', text: '维护' },
+};
+
+const severityMap: Record<string, { color: string; text: string }> = {
+  critical: { color: 'red', text: '严重' },
+  warning: { color: 'orange', text: '警告' },
+  info: { color: 'blue', text: '信息' },
+};
+
+const alarmStatusMap: Record<string, { color: string; text: string }> = {
+  active: { color: 'red', text: '活跃' },
+  acknowledged: { color: 'orange', text: '已确认' },
+  resolved: { color: 'green', text: '已解决' },
+};
+
+const protocolLabels: Record<string, string> = {
+  modbus_tcp: 'Modbus TCP',
+  modbus_rtu: 'Modbus RTU',
+  opc_ua: 'OPC UA',
+  mqtt: 'MQTT',
+  http_api: 'HTTP API',
+  dlt645: 'DL/T 645',
+  image: '图像采集',
+};
+
+const dataTypeOptions = [
+  { label: '功率 (kW)', value: 'power' },
+  { label: '电量 (kWh)', value: 'energy' },
+  { label: '温度 (°C)', value: 'temperature' },
+  { label: 'COP', value: 'cop' },
+  { label: '电流 (A)', value: 'current' },
+  { label: '电压 (V)', value: 'voltage' },
+  { label: '频率 (Hz)', value: 'frequency' },
+  { label: '功率因数', value: 'power_factor' },
+  { label: '流量 (m³/h)', value: 'flow_rate' },
+  { label: '湿度 (%)', value: 'humidity' },
+];
+
+const granularityOptions = [
+  { label: '原始数据', value: 'raw' },
+  { label: '5分钟', value: '5min' },
+  { label: '小时', value: 'hour' },
+  { label: '天', value: 'day' },
+];
+
+const timeRangePresets = [
+  { label: '24小时', value: '24h' },
+  { label: '7天', value: '7d' },
+  { label: '30天', value: '30d' },
+];
+
+function getTimeRange(preset: string): [dayjs.Dayjs, dayjs.Dayjs] {
+  const now = dayjs();
+  switch (preset) {
+    case '24h': return [now.subtract(24, 'hour'), now];
+    case '7d': return [now.subtract(7, 'day'), now];
+    case '30d': return [now.subtract(30, 'day'), now];
+    default: return [now.subtract(24, 'hour'), now];
+  }
+}
+
+export default function DeviceDetail() {
+  const { id } = useParams<{ id: string }>();
+  const navigate = useNavigate();
+  const deviceId = Number(id);
+
+  const [device, setDevice] = useState<any>(null);
+  const [loading, setLoading] = useState(true);
+  const [activeTab, setActiveTab] = useState('realtime');
+
+  // Realtime state
+  const [realtimeData, setRealtimeData] = useState<any>(null);
+  const [realtimeLoading, setRealtimeLoading] = useState(false);
+
+  // History state
+  const [historyData, setHistoryData] = useState<any[]>([]);
+  const [historyLoading, setHistoryLoading] = useState(false);
+  const [dataType, setDataType] = useState('power');
+  const [granularity, setGranularity] = useState('hour');
+  const [timePreset, setTimePreset] = useState('24h');
+  const [timeRange, setTimeRange] = useState<[dayjs.Dayjs, dayjs.Dayjs]>(getTimeRange('24h'));
+
+  // Alarm state
+  const [alarmData, setAlarmData] = useState<any>({ total: 0, items: [] });
+  const [alarmLoading, setAlarmLoading] = useState(false);
+  const [alarmPage, setAlarmPage] = useState(1);
+
+  // Load device info
+  useEffect(() => {
+    if (!deviceId) return;
+    setLoading(true);
+    getDevice(deviceId)
+      .then((res: any) => setDevice(res))
+      .catch(() => message.error('加载设备信息失败'))
+      .finally(() => setLoading(false));
+  }, [deviceId]);
+
+  // Load realtime data
+  const loadRealtime = useCallback(async () => {
+    if (!deviceId) return;
+    setRealtimeLoading(true);
+    try {
+      const res = await getDeviceRealtime(deviceId);
+      setRealtimeData(res);
+    } catch { setRealtimeData(null); }
+    finally { setRealtimeLoading(false); }
+  }, [deviceId]);
+
+  // Auto-refresh realtime every 15s
+  useEffect(() => {
+    if (activeTab !== 'realtime') return;
+    loadRealtime();
+    const timer = setInterval(loadRealtime, 15000);
+    return () => clearInterval(timer);
+  }, [activeTab, loadRealtime]);
+
+  // Load history data
+  const loadHistory = useCallback(async () => {
+    if (!deviceId) return;
+    setHistoryLoading(true);
+    try {
+      const res = await getEnergyHistory({
+        device_id: deviceId,
+        data_type: dataType,
+        granularity,
+        start_time: timeRange[0].format('YYYY-MM-DD HH:mm:ss'),
+        end_time: timeRange[1].format('YYYY-MM-DD HH:mm:ss'),
+        page_size: 1000,
+      });
+      setHistoryData(res as any[]);
+    } catch { setHistoryData([]); }
+    finally { setHistoryLoading(false); }
+  }, [deviceId, dataType, granularity, timeRange]);
+
+  useEffect(() => {
+    if (activeTab === 'history') loadHistory();
+  }, [activeTab, loadHistory]);
+
+  // Load alarm events
+  const loadAlarms = useCallback(async () => {
+    if (!deviceId) return;
+    setAlarmLoading(true);
+    try {
+      const res = await getAlarmEvents({ device_id: deviceId, page: alarmPage, page_size: 20 });
+      setAlarmData(res as any);
+    } catch { setAlarmData({ total: 0, items: [] }); }
+    finally { setAlarmLoading(false); }
+  }, [deviceId, alarmPage]);
+
+  useEffect(() => {
+    if (activeTab === 'alarms') loadAlarms();
+  }, [activeTab, loadAlarms]);
+
+  const handleTimePreset = (preset: string) => {
+    setTimePreset(preset);
+    setTimeRange(getTimeRange(preset));
+  };
+
+  const handleRangeChange = (dates: any) => {
+    if (dates && dates[0] && dates[1]) {
+      setTimePreset('');
+      setTimeRange([dates[0], dates[1]]);
+    }
+  };
+
+  // ---- Chart options ----
+  const getChartOption = () => {
+    const isRaw = granularity === 'raw';
+    const times = historyData.map(d => isRaw ? d.timestamp : d.time);
+    const typeLabel = dataTypeOptions.find(o => o.value === dataType)?.label || dataType;
+
+    if (isRaw) {
+      return {
+        tooltip: { trigger: 'axis' },
+        legend: { data: [typeLabel] },
+        grid: { left: 60, right: 30, top: 40, bottom: 40 },
+        xAxis: { type: 'category', data: times, axisLabel: { rotate: 30 } },
+        yAxis: { type: 'value', name: typeLabel },
+        series: [{
+          name: typeLabel,
+          type: 'line',
+          data: historyData.map(d => d.value),
+          smooth: true,
+          lineStyle: { width: 2 },
+          areaStyle: { opacity: 0.1 },
+        }],
+      };
+    }
+
+    // Aggregated data with avg/max/min
+    const avgData = historyData.map(d => d.avg);
+    const maxData = historyData.map(d => d.max);
+    const minData = historyData.map(d => d.min);
+    const avgVal = avgData.length ? (avgData.reduce((a, b) => a + b, 0) / avgData.length).toFixed(2) : '-';
+    const maxVal = maxData.length ? Math.max(...maxData).toFixed(2) : '-';
+    const minVal = minData.length ? Math.min(...minData).toFixed(2) : '-';
+
+    return {
+      tooltip: { trigger: 'axis' },
+      legend: {
+        data: [
+          `平均 (${avgVal})`,
+          `最大 (${maxVal})`,
+          `最小 (${minVal})`,
+        ],
+      },
+      grid: { left: 60, right: 30, top: 50, bottom: 40 },
+      xAxis: { type: 'category', data: times, axisLabel: { rotate: 30 } },
+      yAxis: { type: 'value', name: typeLabel },
+      series: [
+        {
+          name: `平均 (${avgVal})`,
+          type: 'line',
+          data: avgData,
+          smooth: true,
+          lineStyle: { width: 2, color: '#1890ff' },
+          itemStyle: { color: '#1890ff' },
+          areaStyle: { opacity: 0.08, color: '#1890ff' },
+        },
+        {
+          name: `最大 (${maxVal})`,
+          type: 'line',
+          data: maxData,
+          smooth: true,
+          lineStyle: { width: 1, type: 'dashed', color: '#ff4d4f' },
+          itemStyle: { color: '#ff4d4f' },
+        },
+        {
+          name: `最小 (${minVal})`,
+          type: 'line',
+          data: minData,
+          smooth: true,
+          lineStyle: { width: 1, type: 'dashed', color: '#52c41a' },
+          itemStyle: { color: '#52c41a' },
+        },
+      ],
+    };
+  };
+
+  // ---- Alarm columns ----
+  const alarmColumns = [
+    {
+      title: '时间', dataIndex: 'triggered_at', width: 170,
+      render: (v: string) => v ? dayjs(v).format('YYYY-MM-DD HH:mm:ss') : '-',
+    },
+    { title: '标题', dataIndex: 'title', width: 200, ellipsis: true },
+    {
+      title: '严重程度', dataIndex: 'severity', width: 90,
+      render: (v: string) => {
+        const s = severityMap[v] || { color: 'default', text: v };
+        return <Tag color={s.color}>{s.text}</Tag>;
+      },
+    },
+    {
+      title: '状态', dataIndex: 'status', width: 90,
+      render: (v: string) => {
+        const s = alarmStatusMap[v] || { color: 'default', text: v };
+        return <Tag color={s.color}>{s.text}</Tag>;
+      },
+    },
+    {
+      title: '实际值', dataIndex: 'value', width: 100,
+      render: (v: number) => v != null ? v.toFixed(2) : '-',
+    },
+    {
+      title: '阈值', dataIndex: 'threshold', width: 100,
+      render: (v: number) => v != null ? v.toFixed(2) : '-',
+    },
+    {
+      title: '解决时间', dataIndex: 'resolved_at', width: 170,
+      render: (v: string) => v ? dayjs(v).format('YYYY-MM-DD HH:mm:ss') : '-',
+    },
+  ];
+
+  // ---- Render metric cards for realtime ----
+  const renderRealtimeMetrics = () => {
+    if (!realtimeData?.data) return <Empty description="暂无实时数据" />;
+    const entries = Object.entries(realtimeData.data) as [string, any][];
+    return (
+      <Row gutter={[16, 16]}>
+        {entries.map(([key, val]) => {
+          let icon = <DashboardOutlined />;
+          let color: string | undefined;
+          if (key.includes('power') || key.includes('功率')) { icon = <ThunderboltOutlined />; color = '#1890ff'; }
+          else if (key.includes('temp') || key.includes('温度')) { icon = <FireOutlined />; color = '#fa541c'; }
+          else if (key.includes('cop') || key.includes('COP')) { icon = <ExperimentOutlined />; color = '#52c41a'; }
+          return (
+            <Col xs={12} sm={8} md={6} key={key}>
+              <Card size="small" hoverable>
+                <Statistic
+                  title={key}
+                  value={val.value}
+                  suffix={val.unit || ''}
+                  prefix={icon}
+                  valueStyle={color ? { color } : undefined}
+                />
+              </Card>
+            </Col>
+          );
+        })}
+      </Row>
+    );
+  };
+
+  if (loading) {
+    return <div style={{ textAlign: 'center', padding: 100 }}><Spin size="large" tip="加载中..." /></div>;
+  }
+
+  if (!device) {
+    return <Empty description="设备不存在" style={{ padding: 100 }}>
+      <Button type="primary" onClick={() => navigate('/devices')}>返回设备列表</Button>
+    </Empty>;
+  }
+
+  const st = statusMap[device.status] || { color: 'default', text: device.status || '-' };
+
+  return (
+    <div>
+      {/* Header */}
+      <Card size="small" style={{ marginBottom: 16 }}>
+        <div style={{ display: 'flex', gap: 24, alignItems: 'flex-start' }}>
+          <img
+            src={getDevicePhoto(device.device_type)}
+            alt={device.name}
+            style={{ width: 160, height: 120, borderRadius: 12, objectFit: 'cover', border: '1px solid #f0f0f0', flexShrink: 0 }}
+          />
+          <div style={{ flex: 1 }}>
+            <div style={{ display: 'flex', alignItems: 'center', gap: 12, marginBottom: 12 }}>
+              <h2 style={{ margin: 0, fontSize: 20 }}>{device.name}</h2>
+              <Tag color={st.color}>{st.text}</Tag>
+              <Tag>{device.code}</Tag>
+            </div>
+            <Row gutter={[24, 8]}>
+              <Col span={6}><span style={{ color: '#999' }}>型号：</span>{device.model || '-'}</Col>
+              <Col span={6}><span style={{ color: '#999' }}>厂商：</span>{device.manufacturer || '-'}</Col>
+              <Col span={6}><span style={{ color: '#999' }}>额定功率：</span>{device.rated_power != null ? `${device.rated_power} kW` : '-'}</Col>
+              <Col span={6}><span style={{ color: '#999' }}>位置：</span>{device.location || '-'}</Col>
+              <Col span={6}><span style={{ color: '#999' }}>协议：</span>{protocolLabels[device.protocol] || device.protocol || '-'}</Col>
+              <Col span={6}><span style={{ color: '#999' }}>采集间隔：</span>{device.collect_interval ? `${device.collect_interval}s` : '-'}</Col>
+              <Col span={6}><span style={{ color: '#999' }}>最近数据：</span>{device.last_data_time || '-'}</Col>
+            </Row>
+          </div>
+          <Button icon={<ArrowLeftOutlined />} onClick={() => navigate('/devices')}>
+            返回设备列表
+          </Button>
+        </div>
+      </Card>
+
+      {/* Tabs */}
+      <Card size="small">
+        <Tabs activeKey={activeTab} onChange={setActiveTab} items={[
+          {
+            key: 'realtime',
+            label: '实时数据',
+            children: (
+              <Spin spinning={realtimeLoading}>
+                <div style={{ marginBottom: 16 }}>
+                  <Button icon={<ReloadOutlined />} onClick={loadRealtime} size="small">刷新</Button>
+                  <span style={{ marginLeft: 12, color: '#999', fontSize: 12 }}>每15秒自动刷新</span>
+                </div>
+                {renderRealtimeMetrics()}
+              </Spin>
+            ),
+          },
+          {
+            key: 'history',
+            label: '历史趋势',
+            children: (
+              <div>
+                <Space wrap style={{ marginBottom: 16 }}>
+                  <Select
+                    value={dataType}
+                    onChange={setDataType}
+                    options={dataTypeOptions}
+                    style={{ width: 150 }}
+                  />
+                  <Select
+                    value={granularity}
+                    onChange={setGranularity}
+                    options={granularityOptions}
+                    style={{ width: 120 }}
+                  />
+                  {timeRangePresets.map(p => (
+                    <Button
+                      key={p.value}
+                      type={timePreset === p.value ? 'primary' : 'default'}
+                      size="small"
+                      onClick={() => handleTimePreset(p.value)}
+                    >
+                      {p.label}
+                    </Button>
+                  ))}
+                  <RangePicker
+                    showTime
+                    value={timeRange}
+                    onChange={handleRangeChange}
+                    size="small"
+                  />
+                  <Button icon={<ReloadOutlined />} size="small" onClick={loadHistory}>刷新</Button>
+                </Space>
+                <Spin spinning={historyLoading}>
+                  {historyData.length > 0 ? (
+                    <ReactECharts option={getChartOption()} style={{ height: 400 }} />
+                  ) : (
+                    <Empty description="暂无历史数据" style={{ padding: 60 }} />
+                  )}
+                </Spin>
+              </div>
+            ),
+          },
+          {
+            key: 'alarms',
+            label: '告警记录',
+            children: (
+              <Table
+                columns={alarmColumns}
+                dataSource={alarmData.items}
+                rowKey="id"
+                loading={alarmLoading}
+                size="small"
+                pagination={{
+                  current: alarmPage,
+                  pageSize: 20,
+                  total: alarmData.total,
+                  showTotal: (total: number) => `共 ${total} 条告警`,
+                  onChange: (page: number) => setAlarmPage(page),
+                }}
+              />
+            ),
+          },
+          {
+            key: 'info',
+            label: '设备信息',
+            children: (
+              <Descriptions column={2} bordered size="small">
+                <Descriptions.Item label="设备名称">{device.name}</Descriptions.Item>
+                <Descriptions.Item label="设备编号">{device.code}</Descriptions.Item>
+                <Descriptions.Item label="设备类型">{device.device_type || '-'}</Descriptions.Item>
+                <Descriptions.Item label="设备分组ID">{device.group_id || '-'}</Descriptions.Item>
+                <Descriptions.Item label="型号">{device.model || '-'}</Descriptions.Item>
+                <Descriptions.Item label="厂商">{device.manufacturer || '-'}</Descriptions.Item>
+                <Descriptions.Item label="序列号">{device.serial_number || '-'}</Descriptions.Item>
+                <Descriptions.Item label="额定功率">{device.rated_power != null ? `${device.rated_power} kW` : '-'}</Descriptions.Item>
+                <Descriptions.Item label="位置">{device.location || '-'}</Descriptions.Item>
+                <Descriptions.Item label="通信协议">{protocolLabels[device.protocol] || device.protocol || '-'}</Descriptions.Item>
+                <Descriptions.Item label="采集间隔">{device.collect_interval ? `${device.collect_interval} 秒` : '-'}</Descriptions.Item>
+                <Descriptions.Item label="状态">
+                  <Badge status={device.status === 'online' ? 'success' : device.status === 'alarm' ? 'error' : 'default'}
+                    text={st.text} />
+                </Descriptions.Item>
+                <Descriptions.Item label="是否启用">
+                  <Tag color={device.is_active ? 'green' : 'default'}>{device.is_active ? '启用' : '停用'}</Tag>
+                </Descriptions.Item>
+                <Descriptions.Item label="最近数据时间">{device.last_data_time || '-'}</Descriptions.Item>
+                <Descriptions.Item label="连接参数" span={2}>
+                  {device.connection_params ? (
+                    <pre style={{ margin: 0, fontSize: 12, background: '#f5f5f5', padding: 8, borderRadius: 4, maxHeight: 200, overflow: 'auto' }}>
+                      {JSON.stringify(device.connection_params, null, 2)}
+                    </pre>
+                  ) : '-'}
+                </Descriptions.Item>
+              </Descriptions>
+            ),
+          },
+        ]} />
+      </Card>
+    </div>
+  );
+}
diff --git a/frontend/src/pages/Devices/index.tsx b/frontend/src/pages/Devices/index.tsx
index b480d28..ecdacd0 100644
--- a/frontend/src/pages/Devices/index.tsx
+++ b/frontend/src/pages/Devices/index.tsx
@@ -1,4 +1,5 @@
 import { useEffect, useState, useCallback } from 'react';
+import { useNavigate } from 'react-router-dom';
 import { Card, Table, Tag, Button, Modal, Form, Input, Select, InputNumber, Space, Row, Col, Statistic, Switch, message } from 'antd';
 import { PlusOutlined, EditOutlined, DeleteOutlined, ApiOutlined, CheckCircleOutlined, CloseCircleOutlined, WarningOutlined, AppstoreOutlined } from '@ant-design/icons';
 import { getDevices, getDeviceTypes, getDeviceGroups, getDeviceStats, createDevice, updateDevice } from '../../services/api';
@@ -22,6 +23,7 @@ const protocolOptions = [
 ];
 
 export default function Devices() {
+  const navigate = useNavigate();
   const [data, setData] = useState<any>({ total: 0, items: [] });
   const [stats, setStats] = useState<any>({ online: 0, offline: 0, alarm: 0, total: 0 });
   const [deviceTypes, setDeviceTypes] = useState<any[]>([]);
@@ -118,7 +120,9 @@ export default function Devices() {
     { title: '', dataIndex: 'device_type', width: 50, render: (_: any, record: any) => (
       <img src={getDevicePhoto(record.device_type || record.device_type_id)} alt="" style={{ width: 40, height: 40, borderRadius: 8, objectFit: 'cover' }} />
     )},
-    { title: '设备名称', dataIndex: 'name', width: 160, ellipsis: true },
+    { title: '设备名称', dataIndex: 'name', width: 160, ellipsis: true, render: (name: string, record: any) => (
+      <a onClick={() => navigate(`/devices/${record.id}`)}>{name}</a>
+    )},
     { title: '设备编号', dataIndex: 'code', width: 130 },
     { title: '设备类型', dataIndex: 'device_type_name', width: 120, render: (v: string) => v ? <Tag icon={<AppstoreOutlined />} color="blue">{v}</Tag> : '-' },
     { title: '设备分组', dataIndex: 'device_group_name', width: 120 },
diff --git a/frontend/src/pages/Monitoring/index.tsx b/frontend/src/pages/Monitoring/index.tsx
index 6c42d2f..07332d2 100644
--- a/frontend/src/pages/Monitoring/index.tsx
+++ b/frontend/src/pages/Monitoring/index.tsx
@@ -1,6 +1,7 @@
 import { useEffect, useState } from 'react';
-import { Card, Table, Tag, Input, Select, Descriptions, Modal, Badge, message } from 'antd';
-import { getDevices, getDeviceRealtime } from '../../services/api';
+import { useNavigate } from 'react-router-dom';
+import { Card, Table, Tag, Input, Select, message } from 'antd';
+import { getDevices } from '../../services/api';
 import { getDevicePhoto } from '../../utils/devicePhoto';
 
 const statusMap: Record<string, { color: string; text: string }> = {
@@ -16,10 +17,9 @@ const typeMap: Record<string, string> = {
 };
 
 export default function Monitoring() {
+  const navigate = useNavigate();
   const [devices, setDevices] = useState<any[]>([]);
   const [loading, setLoading] = useState(true);
-  const [selectedDevice, setSelectedDevice] = useState<any>(null);
-  const [deviceData, setDeviceData] = useState<any>(null);
   const [filter, setFilter] = useState({ type: '', search: '' });
 
   useEffect(() => {
@@ -36,14 +36,6 @@ export default function Monitoring() {
     finally { setLoading(false); }
   };
 
-  const showDetail = async (device: any) => {
-    setSelectedDevice(device);
-    try {
-      const data = await getDeviceRealtime(device.id);
-      setDeviceData(data);
-    } catch { setDeviceData(null); }
-  };
-
   const filteredDevices = devices.filter(d => {
     if (filter.type && d.device_type !== filter.type) return false;
     if (filter.search && !d.name.includes(filter.search) && !d.code.includes(filter.search)) return false;
@@ -64,7 +56,7 @@ export default function Monitoring() {
       const st = statusMap[s] || { color: 'default', text: s };
       return <Tag color={st.color}>{st.text}</Tag>;
     }},
-    { title: '操作', key: 'action', render: (_: any, r: any) => <a onClick={() => showDetail(r)}>查看详情</a> },
+    { title: '操作', key: 'action', render: (_: any, r: any) => <a onClick={() => navigate(`/devices/${r.id}`)}>查看详情</a> },
   ];
 
   return (
@@ -82,35 +74,6 @@ export default function Monitoring() {
           loading={loading} size="small" pagination={{ pageSize: 15 }} />
       </Card>
 
-      <Modal title={selectedDevice?.name} open={!!selectedDevice} onCancel={() => setSelectedDevice(null)}
-        footer={null} width={700}>
-        {deviceData?.device && (
-          <>
-          <div style={{ textAlign: 'center', marginBottom: 16 }}>
-            <img src={getDevicePhoto(deviceData.device.device_type)} alt={deviceData.device.name}
-              style={{ width: 200, height: 150, borderRadius: 12, objectFit: 'cover', border: '1px solid #f0f0f0' }} />
-          </div>
-          <Descriptions column={2} size="small" bordered style={{ marginBottom: 16 }}>
-            <Descriptions.Item label="编号">{deviceData.device.code}</Descriptions.Item>
-            <Descriptions.Item label="类型">{typeMap[deviceData.device.device_type]}</Descriptions.Item>
-            <Descriptions.Item label="型号">{deviceData.device.model || '-'}</Descriptions.Item>
-            <Descriptions.Item label="状态">
-              <Badge status={deviceData.device.status === 'online' ? 'success' : 'error'}
-                text={statusMap[deviceData.device.status]?.text} />
-            </Descriptions.Item>
-          </Descriptions>
-          </>
-        )}
-        {deviceData?.data && (
-          <Descriptions column={2} size="small" bordered title="实时数据">
-            {Object.entries(deviceData.data).map(([key, val]: any) => (
-              <Descriptions.Item key={key} label={key}>
-                {val.value} {val.unit}
-              </Descriptions.Item>
-            ))}
-          </Descriptions>
-        )}
-      </Modal>
     </div>
   );
 }
diff --git a/frontend/src/pages/System/AuditLog.tsx b/frontend/src/pages/System/AuditLog.tsx
new file mode 100644
index 0000000..33c5356
--- /dev/null
+++ b/frontend/src/pages/System/AuditLog.tsx
@@ -0,0 +1,174 @@
+import { useEffect, useState } from 'react';
+import { Card, Table, Tag, Select, DatePicker, Space, Input } from 'antd';
+import { getAuditLogs, getUsers } from '../../services/api';
+import dayjs from 'dayjs';
+
+const { RangePicker } = DatePicker;
+
+const ACTION_COLORS: Record<string, string> = {
+  login: 'blue',
+  create: 'green',
+  update: 'orange',
+  delete: 'red',
+  export: 'purple',
+  view: 'default',
+  acknowledge: 'cyan',
+  resolve: 'geekblue',
+};
+
+const ACTION_LABELS: Record<string, string> = {
+  login: '登录',
+  create: '创建',
+  update: '更新',
+  delete: '删除',
+  export: '导出',
+  view: '查看',
+  acknowledge: '确认',
+  resolve: '解决',
+};
+
+const RESOURCE_LABELS: Record<string, string> = {
+  user: '用户',
+  device: '设备',
+  alarm: '告警',
+  report: '报表',
+  system: '系统',
+  auth: '认证',
+};
+
+export default function AuditLog() {
+  const [data, setData] = useState<{ total: number; items: any[] }>({ total: 0, items: [] });
+  const [users, setUsers] = useState<any[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [filters, setFilters] = useState<Record<string, any>>({
+    page: 1,
+    page_size: 20,
+  });
+
+  useEffect(() => {
+    loadUsers();
+  }, []);
+
+  useEffect(() => {
+    loadData();
+  }, [filters]);
+
+  const loadUsers = async () => {
+    try {
+      const res = await getUsers({ page_size: 100 });
+      setUsers((res as any)?.items || []);
+    } catch {
+      // ignore
+    }
+  };
+
+  const loadData = async () => {
+    setLoading(true);
+    try {
+      const res = await getAuditLogs(filters);
+      setData(res as any);
+    } catch {
+      // ignore
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  const columns = [
+    {
+      title: '时间',
+      dataIndex: 'created_at',
+      width: 180,
+      render: (v: string) => v ? dayjs(v).format('YYYY-MM-DD HH:mm:ss') : '-',
+    },
+    {
+      title: '用户',
+      dataIndex: 'username',
+      width: 120,
+    },
+    {
+      title: '操作',
+      dataIndex: 'action',
+      width: 100,
+      render: (v: string) => (
+        <Tag color={ACTION_COLORS[v] || 'default'}>{ACTION_LABELS[v] || v}</Tag>
+      ),
+    },
+    {
+      title: '资源',
+      dataIndex: 'resource',
+      width: 100,
+      render: (v: string) => RESOURCE_LABELS[v] || v || '-',
+    },
+    {
+      title: '详情',
+      dataIndex: 'detail',
+      ellipsis: true,
+    },
+    {
+      title: 'IP地址',
+      dataIndex: 'ip_address',
+      width: 140,
+      render: (v: string) => v || '-',
+    },
+  ];
+
+  return (
+    <Card
+      title="审计日志"
+      size="small"
+      extra={
+        <Space wrap>
+          <Select
+            placeholder="用户"
+            allowClear
+            style={{ width: 140 }}
+            options={users.map((u: any) => ({ label: u.full_name || u.username, value: u.id }))}
+            onChange={(v) => setFilters({ ...filters, user_id: v, page: 1 })}
+          />
+          <Select
+            placeholder="操作类型"
+            allowClear
+            style={{ width: 120 }}
+            options={Object.entries(ACTION_LABELS).map(([k, v]) => ({ label: v, value: k }))}
+            onChange={(v) => setFilters({ ...filters, action: v, page: 1 })}
+          />
+          <Select
+            placeholder="资源类型"
+            allowClear
+            style={{ width: 120 }}
+            options={Object.entries(RESOURCE_LABELS).map(([k, v]) => ({ label: v, value: k }))}
+            onChange={(v) => setFilters({ ...filters, resource: v, page: 1 })}
+          />
+          <RangePicker
+            showTime
+            onChange={(dates) => {
+              setFilters({
+                ...filters,
+                start_time: dates?.[0]?.toISOString(),
+                end_time: dates?.[1]?.toISOString(),
+                page: 1,
+              });
+            }}
+          />
+        </Space>
+      }
+    >
+      <Table
+        columns={columns}
+        dataSource={data.items}
+        rowKey="id"
+        loading={loading}
+        size="small"
+        pagination={{
+          current: filters.page,
+          pageSize: filters.page_size,
+          total: data.total,
+          showSizeChanger: true,
+          showTotal: (total) => `共 ${total} 条`,
+          onChange: (page, pageSize) => setFilters({ ...filters, page, page_size: pageSize }),
+        }}
+      />
+    </Card>
+  );
+}
diff --git a/frontend/src/pages/System/Settings.tsx b/frontend/src/pages/System/Settings.tsx
new file mode 100644
index 0000000..5c9e014
--- /dev/null
+++ b/frontend/src/pages/System/Settings.tsx
@@ -0,0 +1,110 @@
+import { useEffect, useState } from 'react';
+import { Card, Form, Input, InputNumber, Switch, Select, Button, message, Spin, Row, Col } from 'antd';
+import { SaveOutlined } from '@ant-design/icons';
+import { getSettings, updateSettings } from '../../services/api';
+import { getUser } from '../../utils/auth';
+
+const TIMEZONE_OPTIONS = [
+  { label: 'Asia/Shanghai (UTC+8)', value: 'Asia/Shanghai' },
+  { label: 'Asia/Tokyo (UTC+9)', value: 'Asia/Tokyo' },
+  { label: 'Asia/Singapore (UTC+8)', value: 'Asia/Singapore' },
+  { label: 'UTC', value: 'UTC' },
+  { label: 'America/New_York (UTC-5)', value: 'America/New_York' },
+  { label: 'Europe/London (UTC+0)', value: 'Europe/London' },
+];
+
+export default function SystemSettings() {
+  const [form] = Form.useForm();
+  const [loading, setLoading] = useState(true);
+  const [saving, setSaving] = useState(false);
+  const user = getUser();
+  const isAdmin = user?.role === 'admin';
+
+  useEffect(() => {
+    loadSettings();
+  }, []);
+
+  const loadSettings = async () => {
+    setLoading(true);
+    try {
+      const res = await getSettings();
+      form.setFieldsValue(res as any);
+    } catch {
+      message.error('加载设置失败');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  const handleSave = async () => {
+    try {
+      const values = await form.validateFields();
+      setSaving(true);
+      await updateSettings(values);
+      message.success('设置已保存');
+    } catch (e: any) {
+      if (e?.detail) message.error(e.detail);
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  if (loading) return <Spin style={{ display: 'block', margin: '80px auto' }} />;
+
+  return (
+    <Form form={form} layout="vertical" disabled={!isAdmin}>
+      <Row gutter={16}>
+        <Col xs={24} lg={12}>
+          <Card title="基本设置" size="small" style={{ marginBottom: 16 }}>
+            <Form.Item name="platform_name" label="平台名称" rules={[{ required: true }]}>
+              <Input />
+            </Form.Item>
+            <Form.Item name="timezone" label="时区">
+              <Select options={TIMEZONE_OPTIONS} />
+            </Form.Item>
+          </Card>
+
+          <Card title="数据管理" size="small" style={{ marginBottom: 16 }}>
+            <Form.Item name="data_retention_days" label="数据保留天数">
+              <InputNumber min={30} max={3650} addonAfter="天" style={{ width: '100%' }} />
+            </Form.Item>
+            <Form.Item name="simulator_interval_seconds" label="模拟器采集间隔">
+              <InputNumber min={5} max={300} addonAfter="秒" style={{ width: '100%' }} />
+            </Form.Item>
+          </Card>
+        </Col>
+
+        <Col xs={24} lg={12}>
+          <Card title="告警设置" size="small" style={{ marginBottom: 16 }}>
+            <Form.Item name="alarm_auto_resolve_minutes" label="告警自动解除时间">
+              <InputNumber min={5} max={1440} addonAfter="分钟" style={{ width: '100%' }} />
+            </Form.Item>
+          </Card>
+
+          <Card title="通知设置" size="small" style={{ marginBottom: 16 }}>
+            <Form.Item name="notification_email_enabled" label="邮件通知" valuePropName="checked">
+              <Switch />
+            </Form.Item>
+            <Form.Item name="notification_email_smtp" label="SMTP 服务器">
+              <Input placeholder="smtp.example.com:465" />
+            </Form.Item>
+          </Card>
+
+          <Card title="报表设置" size="small" style={{ marginBottom: 16 }}>
+            <Form.Item name="report_auto_schedule_enabled" label="自动生成报表" valuePropName="checked">
+              <Switch />
+            </Form.Item>
+          </Card>
+        </Col>
+      </Row>
+
+      {isAdmin && (
+        <div style={{ textAlign: 'right', marginTop: 8 }}>
+          <Button type="primary" icon={<SaveOutlined />} onClick={handleSave} loading={saving}>
+            保存设置
+          </Button>
+        </div>
+      )}
+    </Form>
+  );
+}
diff --git a/frontend/src/pages/System/index.tsx b/frontend/src/pages/System/index.tsx
index ac60bde..9b05b51 100644
--- a/frontend/src/pages/System/index.tsx
+++ b/frontend/src/pages/System/index.tsx
@@ -1,7 +1,10 @@
 import { useEffect, useState } from 'react';
 import { Card, Table, Button, Tag, Modal, Form, Input, Select, Switch, message, Tabs } from 'antd';
 import { PlusOutlined, EditOutlined } from '@ant-design/icons';
+import { useNavigate, useLocation } from 'react-router-dom';
 import { getUsers, createUser, updateUser, getRoles } from '../../services/api';
+import AuditLog from './AuditLog';
+import SystemSettings from './Settings';
 
 export default function SystemManagement() {
   const [users, setUsers] = useState<any>({ total: 0, items: [] });
@@ -10,6 +13,18 @@ export default function SystemManagement() {
   const [showModal, setShowModal] = useState(false);
   const [editingUser, setEditingUser] = useState<any>(null);
   const [form] = Form.useForm();
+  const navigate = useNavigate();
+  const location = useLocation();
+
+  // Derive active tab from URL path
+  const pathSegment = location.pathname.split('/').pop() || 'users';
+  const tabKeyMap: Record<string, string> = {
+    users: 'users',
+    roles: 'roles',
+    settings: 'settings',
+    audit: 'audit',
+  };
+  const activeTab = tabKeyMap[pathSegment] || 'users';
 
   useEffect(() => { loadData(); }, []);
 
@@ -70,21 +85,31 @@ export default function SystemManagement() {
     { title: '描述', dataIndex: 'description' },
   ];
 
+  const handleTabChange = (key: string) => {
+    navigate(`/system/${key}`);
+  };
+
   return (
     <>
-      <Tabs items={[
-        { key: 'users', label: '用户管理', children: (
-          <Card size="small" extra={<Button type="primary" icon={<PlusOutlined />}
-            onClick={() => { setEditingUser(null); form.resetFields(); setShowModal(true); }}>新建用户</Button>}>
-            <Table columns={columns} dataSource={users.items} rowKey="id" loading={loading} size="small" />
-          </Card>
-        )},
-        { key: 'roles', label: '角色管理', children: (
-          <Card size="small">
-            <Table columns={roleColumns} dataSource={roles} rowKey="id" loading={loading} size="small" />
-          </Card>
-        )},
-      ]} />
+      <Tabs
+        activeKey={activeTab}
+        onChange={handleTabChange}
+        items={[
+          { key: 'users', label: '用户管理', children: (
+            <Card size="small" extra={<Button type="primary" icon={<PlusOutlined />}
+              onClick={() => { setEditingUser(null); form.resetFields(); setShowModal(true); }}>新建用户</Button>}>
+              <Table columns={columns} dataSource={users.items} rowKey="id" loading={loading} size="small" />
+            </Card>
+          )},
+          { key: 'roles', label: '角色管理', children: (
+            <Card size="small">
+              <Table columns={roleColumns} dataSource={roles} rowKey="id" loading={loading} size="small" />
+            </Card>
+          )},
+          { key: 'settings', label: '系统设置', children: <SystemSettings /> },
+          { key: 'audit', label: '审计日志', children: <AuditLog /> },
+        ]}
+      />
       <Modal title={editingUser ? '编辑用户' : '新建用户'} open={showModal}
         onCancel={() => { setShowModal(false); setEditingUser(null); }}
         onOk={() => form.submit()} okText="确定">
diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index f0d5aaf..a17e43e 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -131,4 +131,11 @@ export const createUser = (data: any) => api.post('/users', data);
 export const updateUser = (id: number, data: any) => api.put(`/users/${id}`, data);
 export const getRoles = () => api.get('/users/roles');
 
+// Audit Logs
+export const getAuditLogs = (params?: Record<string, any>) => api.get('/audit/logs', { params });
+
+// System Settings
+export const getSettings = () => api.get('/settings');
+export const updateSettings = (data: any) => api.put('/settings', data);
+
 export default api;
diff --git a/scripts/seed_data.py b/scripts/seed_data.py
index a659b66..f165355 100644
--- a/scripts/seed_data.py
+++ b/scripts/seed_data.py
@@ -14,7 +14,7 @@ from app.models.user import User, Role
 from app.models.device import Device, DeviceType, DeviceGroup
 from app.models.alarm import AlarmRule, AlarmEvent
 from app.models.carbon import EmissionFactor
-from app.models.report import ReportTemplate
+from app.models.report import ReportTemplate, ReportTask
 
 
 async def seed():
@@ -283,7 +283,8 @@ async def seed():
                 threshold=0.0,
                 duration=3600,
                 severity="critical",
-                notify_channels=["app", "sms", "wechat"],
+                notify_channels=["app", "sms", "wechat", "email"],
+                notify_targets={"emails": ["admin@tianpu.com", "energy@tianpu.com"]},
                 is_active=True,
             ),
             AlarmRule(
@@ -294,7 +295,8 @@ async def seed():
                 threshold=38.0,
                 duration=300,
                 severity="critical",
-                notify_channels=["app", "sms"],
+                notify_channels=["app", "sms", "email"],
+                notify_targets={"emails": ["admin@tianpu.com"]},
                 is_active=True,
             ),
             AlarmRule(
@@ -376,6 +378,24 @@ async def seed():
 
         await session.flush()
 
+        # =====================================================================
+        # 8b. 定时报表任务 (daily report at 8am)
+        # =====================================================================
+        report_tasks = [
+            ReportTask(
+                template_id=1,  # 日报模板
+                name="每日能源运行日报",
+                schedule="0 8 * * *",
+                recipients=["admin@tianpu.com"],
+                export_format="xlsx",
+                status="pending",
+                is_active=True,
+                created_by=1,
+            ),
+        ]
+        session.add_all(report_tasks)
+        await session.flush()
+
         # =====================================================================
         # 9. 历史告警事件 (15 events over last 7 days)
         # =====================================================================
@@ -545,6 +565,7 @@ async def seed():
         print(f"  - {len(alarm_rules)} alarm rules")
         print(f"  - {len(factors)} emission factors")
         print(f"  - {len(templates)} report templates")
+        print(f"  - {len(report_tasks)} report tasks (scheduled)")
         print(f"  - {len(alarm_events)} alarm events (historical)")
 
     await engine.dispose()