diff --git a/backend/internal/service/notification_email_service.go b/backend/internal/service/notification_email_service.go
index 5b758339..ba281915 100644
--- a/backend/internal/service/notification_email_service.go
+++ b/backend/internal/service/notification_email_service.go
@@ -20,10 +20,18 @@ import (
 )
 
 const (
+	NotificationEmailEventAuthVerifyCode              = "auth.verify_code"
+	NotificationEmailEventAuthPasswordReset           = "auth.password_reset"
+	NotificationEmailEventNotificationEmailVerifyCode = "notification_email.verify_code"
 	NotificationEmailEventSubscriptionPurchaseSuccess = "subscription.purchase_success"
 	NotificationEmailEventSubscriptionExpiryReminder  = "subscription.expiry_reminder"
 	NotificationEmailEventBalanceLow                  = "balance.low"
 	NotificationEmailEventBalanceRechargeSuccess      = "balance.recharge_success"
+	NotificationEmailEventAccountQuotaAlert           = "account.quota_alert"
+	NotificationEmailEventContentModerationViolation  = "content_moderation.violation_notice"
+	NotificationEmailEventContentModerationDisabled   = "content_moderation.account_disabled"
+	NotificationEmailEventOpsAlert                    = "ops.alert"
+	NotificationEmailEventOpsScheduledReport          = "ops.scheduled_report"
 
 	notificationEmailTemplateKeyPrefix    = "notification_email_template:"
 	notificationEmailPreferenceKeyPrefix  = "notification_email_preference:"
@@ -82,15 +90,16 @@ type NotificationEmailPreviewInput struct {
 }
 
 type NotificationEmailSendInput struct {
-	Event          string
-	Locale         string
-	RecipientEmail string
-	RecipientName  string
-	UserID         int64
-	SourceType     string
-	SourceID       string
-	ReminderKey    string
-	Variables      map[string]string
+	Event            string
+	Locale           string
+	RecipientEmail   string
+	RecipientName    string
+	UserID           int64
+	SourceType       string
+	SourceID         string
+	ReminderKey      string
+	Variables        map[string]string
+	RawHTMLVariables map[string]string
 }
 
 type NotificationEmailUnsubscribeResult struct {
@@ -110,6 +119,42 @@ type notificationEmailOfficialTemplate struct {
 	HTML    string
 }
 
+type notificationEmailTemplateError struct {
+	Err error
+}
+
+func (e notificationEmailTemplateError) Error() string {
+	return e.Err.Error()
+}
+
+func (e notificationEmailTemplateError) Unwrap() error {
+	return e.Err
+}
+
+type notificationEmailConfigError struct {
+	Err error
+}
+
+func (e notificationEmailConfigError) Error() string {
+	return e.Err.Error()
+}
+
+func (e notificationEmailConfigError) Unwrap() error {
+	return e.Err
+}
+
+type notificationEmailDeliveryError struct {
+	Err error
+}
+
+func (e notificationEmailDeliveryError) Error() string {
+	return e.Err.Error()
+}
+
+func (e notificationEmailDeliveryError) Unwrap() error {
+	return e.Err
+}
+
 type notificationEmailUnsubscribeClaims struct {
 	Email string `json:"email"`
 	Event string `json:"event"`
@@ -117,7 +162,49 @@ type notificationEmailUnsubscribeClaims struct {
 }
 
 func NewNotificationEmailService(settingRepo SettingRepository, emailService *EmailService) *NotificationEmailService {
-	return &NotificationEmailService{settingRepo: settingRepo, emailService: emailService}
+	svc := &NotificationEmailService{settingRepo: settingRepo, emailService: emailService}
+	if emailService != nil {
+		emailService.SetNotificationEmailService(svc)
+	}
+	return svc
+}
+
+func notificationEmailTemplateErr(err error) error {
+	if err == nil {
+		return nil
+	}
+	return notificationEmailTemplateError{Err: err}
+}
+
+func notificationEmailConfigErr(err error) error {
+	if err == nil {
+		return nil
+	}
+	return notificationEmailConfigError{Err: err}
+}
+
+func notificationEmailDeliveryErr(err error) error {
+	if err == nil {
+		return nil
+	}
+	return notificationEmailDeliveryError{Err: err}
+}
+
+func shouldFallbackNotificationEmail(err error) bool {
+	if err == nil {
+		return false
+	}
+	var templateErr notificationEmailTemplateError
+	if errors.As(err, &templateErr) {
+		return true
+	}
+	var configErr notificationEmailConfigError
+	return errors.As(err, &configErr)
+}
+
+func isNotificationEmailDeliveryError(err error) bool {
+	var deliveryErr notificationEmailDeliveryError
+	return errors.As(err, &deliveryErr)
 }
 
 func (s *NotificationEmailService) ListEventInfos() []NotificationEmailEventInfo {
@@ -256,13 +343,13 @@ func (s *NotificationEmailService) PreviewTemplate(ctx context.Context, input No
 	for key, value := range input.Variables {
 		variables[key] = value
 	}
-	return renderNotificationEmail(normalizedEvent, subject, htmlBody, variables)
+	return renderNotificationEmail(normalizedEvent, subject, htmlBody, variables, nil)
 }
 
 func (s *NotificationEmailService) Send(ctx context.Context, input NotificationEmailSendInput) error {
 	info, normalizedEvent, err := s.eventInfo(input.Event)
 	if err != nil {
-		return err
+		return notificationEmailTemplateErr(err)
 	}
 	recipient := strings.TrimSpace(input.RecipientEmail)
 	if recipient == "" {
@@ -285,12 +372,12 @@ func (s *NotificationEmailService) Send(ctx context.Context, input NotificationE
 	}
 	tmpl, err := s.GetTemplate(ctx, normalizedEvent, locale)
 	if err != nil {
-		return err
+		return notificationEmailTemplateErr(err)
 	}
 	variables := s.runtimeVariables(ctx, normalizedEvent, locale, input)
-	rendered, err := renderNotificationEmail(normalizedEvent, tmpl.Subject, tmpl.HTML, variables)
+	rendered, err := renderNotificationEmail(normalizedEvent, tmpl.Subject, tmpl.HTML, variables, input.RawHTMLVariables)
 	if err != nil {
-		return err
+		return notificationEmailTemplateErr(err)
 	}
 
 	deliveryKey := notificationEmailDeliveryKey(normalizedEvent, input.SourceType, input.SourceID, recipient, input.ReminderKey)
@@ -305,10 +392,10 @@ func (s *NotificationEmailService) Send(ctx context.Context, input NotificationE
 	}
 
 	if s.emailService == nil {
-		return errors.New("email service is not configured")
+		return notificationEmailConfigErr(errors.New("email service is not configured"))
 	}
 	if err := s.emailService.SendEmail(ctx, recipient, rendered.Subject, rendered.HTML); err != nil {
-		return err
+		return notificationEmailDeliveryErr(err)
 	}
 	if deliveryKey != "" {
 		_ = s.settingRepo.Set(ctx, deliveryKey, time.Now().UTC().Format(time.RFC3339Nano))
@@ -557,22 +644,22 @@ func validateNotificationEmailTemplate(event, subject, htmlBody string) error {
 	return nil
 }
 
-func renderNotificationEmail(event, subject, htmlBody string, variables map[string]string) (NotificationEmailPreview, error) {
+func renderNotificationEmail(event, subject, htmlBody string, variables map[string]string, rawHTMLVariables map[string]string) (NotificationEmailPreview, error) {
 	if err := validateNotificationEmailTemplate(event, subject, htmlBody); err != nil {
 		return NotificationEmailPreview{}, err
 	}
-	renderedSubject, err := renderNotificationEmailString(event, subject, variables, false)
+	renderedSubject, err := renderNotificationEmailString(event, subject, variables, nil, false)
 	if err != nil {
 		return NotificationEmailPreview{}, err
 	}
-	renderedHTML, err := renderNotificationEmailString(event, htmlBody, variables, true)
+	renderedHTML, err := renderNotificationEmailString(event, htmlBody, variables, rawHTMLVariables, true)
 	if err != nil {
 		return NotificationEmailPreview{}, err
 	}
 	return NotificationEmailPreview{Subject: sanitizeEmailHeader(renderedSubject), HTML: renderedHTML}, nil
 }
 
-func renderNotificationEmailString(event, raw string, variables map[string]string, escapeHTML bool) (string, error) {
+func renderNotificationEmailString(event, raw string, variables map[string]string, rawHTMLVariables map[string]string, escapeHTML bool) (string, error) {
 	allowed := notificationEmailAllowedPlaceholderSet(event)
 	var renderErr error
 	rendered := notificationEmailPlaceholderPattern.ReplaceAllStringFunc(raw, func(match string) string {
@@ -589,6 +676,13 @@ func renderNotificationEmailString(event, raw string, variables map[string]strin
 			return ""
 		}
 		value := variables[name]
+		if escapeHTML && notificationEmailRawHTMLAllowed(event, name) {
+			if rawHTMLVariables != nil {
+				if rawValue, ok := rawHTMLVariables[name]; ok {
+					return rawValue
+				}
+			}
+		}
 		if strings.HasSuffix(name, "_url") && !isSafeNotificationEmailURL(value) {
 			value = ""
 		}
@@ -603,6 +697,10 @@ func renderNotificationEmailString(event, raw string, variables map[string]strin
 	return rendered, nil
 }
 
+func notificationEmailRawHTMLAllowed(event, placeholder string) bool {
+	return event == NotificationEmailEventOpsScheduledReport && placeholder == "report_html"
+}
+
 func notificationEmailAllowedPlaceholderSet(event string) map[string]struct{} {
 	info := notificationEmailEventDefinitions[event]
 	allowed := make(map[string]struct{}, len(info.Placeholders))
@@ -712,46 +810,138 @@ func isSafeNotificationEmailURL(raw string) bool {
 func notificationEmailSampleVariables(locale string) map[string]string {
 	if normalizeNotificationLocale(locale) == notificationEmailLocaleChinese {
 		return map[string]string{
-			"site_name":          defaultSiteName,
-			"recipient_name":     "张三",
-			"recipient_email":    "user@example.com",
-			"subscription_group": "Claude Pro",
-			"subscription_days":  "30",
-			"expiry_time":        "2026-06-18 12:00",
-			"days_remaining":     "3",
-			"current_balance":    "12.34",
-			"threshold":          "20.00",
-			"recharge_url":       "https://example.com/recharge",
-			"recharge_amount":    "50.00",
-			"order_id":           "1024",
-			"unsubscribe_url":    "https://example.com/unsubscribe",
+			"site_name":           defaultSiteName,
+			"recipient_name":      "张三",
+			"recipient_email":     "user@example.com",
+			"verification_code":   "123456",
+			"expires_in_minutes":  "15",
+			"reset_url":           "https://example.com/reset-password?token=preview",
+			"subscription_group":  "Claude Pro",
+			"subscription_days":   "30",
+			"expiry_time":         "2026-06-18 12:00",
+			"days_remaining":      "3",
+			"current_balance":     "12.34",
+			"threshold":           "20.00",
+			"recharge_url":        "https://example.com/recharge",
+			"recharge_amount":     "50.00",
+			"order_id":            "1024",
+			"unsubscribe_url":     "https://example.com/unsubscribe",
+			"account_id":          "1001",
+			"account_name":        "openai-main",
+			"platform":            "openai",
+			"quota_dimension":     "每日额度",
+			"quota_used":          "80.00",
+			"quota_limit":         "100.00",
+			"quota_remaining":     "20.00",
+			"quota_threshold":     "20%",
+			"triggered_at":        "2026-05-20 12:00:00",
+			"group_name":          "默认分组",
+			"moderation_category": "violence",
+			"moderation_score":    "0.982",
+			"violation_count":     "2",
+			"ban_threshold":       "3",
+			"rule_name":           "错误率过高",
+			"severity":            "critical",
+			"alert_status":        "firing",
+			"metric_type":         "error_rate",
+			"operator":            ">=",
+			"metric_value":        "12.50",
+			"threshold_value":     "10.00",
+			"alert_description":   "最近 10 分钟错误率超过阈值",
+			"report_name":         "日报",
+			"report_type":         "daily_summary",
+			"report_start_time":   "2026-05-19 12:00",
+			"report_end_time":     "2026-05-20 12:00",
+			"report_html":         "<h2>日报</h2><p>请求量：1024</p>",
 		}
 	}
 	return map[string]string{
-		"site_name":          defaultSiteName,
-		"recipient_name":     "Alex",
-		"recipient_email":    "user@example.com",
-		"subscription_group": "Claude Pro",
-		"subscription_days":  "30",
-		"expiry_time":        "2026-06-18 12:00",
-		"days_remaining":     "3",
-		"current_balance":    "12.34",
-		"threshold":          "20.00",
-		"recharge_url":       "https://example.com/recharge",
-		"recharge_amount":    "50.00",
-		"order_id":           "1024",
-		"unsubscribe_url":    "https://example.com/unsubscribe",
+		"site_name":           defaultSiteName,
+		"recipient_name":      "Alex",
+		"recipient_email":     "user@example.com",
+		"verification_code":   "123456",
+		"expires_in_minutes":  "15",
+		"reset_url":           "https://example.com/reset-password?token=preview",
+		"subscription_group":  "Claude Pro",
+		"subscription_days":   "30",
+		"expiry_time":         "2026-06-18 12:00",
+		"days_remaining":      "3",
+		"current_balance":     "12.34",
+		"threshold":           "20.00",
+		"recharge_url":        "https://example.com/recharge",
+		"recharge_amount":     "50.00",
+		"order_id":            "1024",
+		"unsubscribe_url":     "https://example.com/unsubscribe",
+		"account_id":          "1001",
+		"account_name":        "openai-main",
+		"platform":            "openai",
+		"quota_dimension":     "Daily quota",
+		"quota_used":          "80.00",
+		"quota_limit":         "100.00",
+		"quota_remaining":     "20.00",
+		"quota_threshold":     "20%",
+		"triggered_at":        "2026-05-20 12:00:00",
+		"group_name":          "Default group",
+		"moderation_category": "violence",
+		"moderation_score":    "0.982",
+		"violation_count":     "2",
+		"ban_threshold":       "3",
+		"rule_name":           "High error rate",
+		"severity":            "critical",
+		"alert_status":        "firing",
+		"metric_type":         "error_rate",
+		"operator":            ">=",
+		"metric_value":        "12.50",
+		"threshold_value":     "10.00",
+		"alert_description":   "Error rate exceeded threshold in the last 10 minutes.",
+		"report_name":         "Daily summary",
+		"report_type":         "daily_summary",
+		"report_start_time":   "2026-05-19 12:00",
+		"report_end_time":     "2026-05-20 12:00",
+		"report_html":         "<h2>Daily summary</h2><p>Requests: 1024</p>",
 	}
 }
 
 var notificationEmailEventOrder = []string{
+	NotificationEmailEventAuthVerifyCode,
+	NotificationEmailEventAuthPasswordReset,
+	NotificationEmailEventNotificationEmailVerifyCode,
 	NotificationEmailEventSubscriptionPurchaseSuccess,
 	NotificationEmailEventSubscriptionExpiryReminder,
 	NotificationEmailEventBalanceLow,
 	NotificationEmailEventBalanceRechargeSuccess,
+	NotificationEmailEventAccountQuotaAlert,
+	NotificationEmailEventContentModerationViolation,
+	NotificationEmailEventContentModerationDisabled,
+	NotificationEmailEventOpsAlert,
+	NotificationEmailEventOpsScheduledReport,
 }
 
 var notificationEmailEventDefinitions = map[string]NotificationEmailEventInfo{
+	NotificationEmailEventAuthVerifyCode: {
+		Event:        NotificationEmailEventAuthVerifyCode,
+		Label:        "Email verification code",
+		Description:  "Sent for registration, email binding, OAuth pending email, and TOTP verification flows.",
+		Category:     "auth",
+		Optional:     false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...), "verification_code", "expires_in_minutes"),
+	},
+	NotificationEmailEventAuthPasswordReset: {
+		Event:        NotificationEmailEventAuthPasswordReset,
+		Label:        "Password reset",
+		Description:  "Sent when a user requests a password reset link.",
+		Category:     "auth",
+		Optional:     false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...), "reset_url", "expires_in_minutes"),
+	},
+	NotificationEmailEventNotificationEmailVerifyCode: {
+		Event:        NotificationEmailEventNotificationEmailVerifyCode,
+		Label:        "Notification email verification code",
+		Description:  "Sent when a user verifies an extra notification email address.",
+		Category:     "auth",
+		Optional:     false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...), "verification_code", "expires_in_minutes"),
+	},
 	NotificationEmailEventSubscriptionPurchaseSuccess: {
 		Event:        NotificationEmailEventSubscriptionPurchaseSuccess,
 		Label:        "Subscription purchase success",
@@ -784,9 +974,117 @@ var notificationEmailEventDefinitions = map[string]NotificationEmailEventInfo{
 		Optional:     false,
 		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...), "recharge_amount", "current_balance", "order_id"),
 	},
+	NotificationEmailEventAccountQuotaAlert: {
+		Event:       NotificationEmailEventAccountQuotaAlert,
+		Label:       "Account quota alert",
+		Description: "Sent to configured admin notification emails when an upstream account quota threshold is crossed.",
+		Category:    "admin",
+		Optional:    false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...),
+			"account_id", "account_name", "platform", "quota_dimension", "quota_used", "quota_limit", "quota_remaining", "quota_threshold"),
+	},
+	NotificationEmailEventContentModerationViolation: {
+		Event:       NotificationEmailEventContentModerationViolation,
+		Label:       "Risk control violation notice",
+		Description: "Sent to users when a request triggers content moderation/risk control rules.",
+		Category:    "risk_control",
+		Optional:    false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...),
+			"triggered_at", "group_name", "moderation_category", "moderation_score", "violation_count", "ban_threshold"),
+	},
+	NotificationEmailEventContentModerationDisabled: {
+		Event:       NotificationEmailEventContentModerationDisabled,
+		Label:       "Risk control account disabled",
+		Description: "Sent to users when content moderation automatically disables their account.",
+		Category:    "risk_control",
+		Optional:    false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...),
+			"triggered_at", "group_name", "moderation_category", "moderation_score", "violation_count", "ban_threshold"),
+	},
+	NotificationEmailEventOpsAlert: {
+		Event:       NotificationEmailEventOpsAlert,
+		Label:       "Ops alert",
+		Description: "Sent to configured operations recipients when an ops alert rule fires.",
+		Category:    "ops",
+		Optional:    false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...),
+			"rule_name", "severity", "alert_status", "metric_type", "operator", "metric_value", "threshold_value", "triggered_at", "alert_description"),
+	},
+	NotificationEmailEventOpsScheduledReport: {
+		Event:       NotificationEmailEventOpsScheduledReport,
+		Label:       "Ops scheduled report",
+		Description: "Sent to configured operations recipients for scheduled daily/weekly/error/account-health reports.",
+		Category:    "ops",
+		Optional:    false,
+		Placeholders: append(append([]string{}, notificationEmailCommonPlaceholders...),
+			"report_name", "report_type", "report_start_time", "report_end_time", "report_html"),
+	},
 }
 
 var notificationEmailOfficialTemplates = map[string]map[string]notificationEmailOfficialTemplate{
+	NotificationEmailEventAuthVerifyCode: {
+		notificationEmailDefaultLocale: {
+			Subject: "[{{site_name}}] Email verification code",
+			HTML: notificationEmailCard("#4f46e5", "Email verification code", `
+<p>Hello {{recipient_name}},</p>
+<p>Your verification code is:</p>
+<p style="font-size: 32px; font-weight: 700; letter-spacing: 8px; text-align: center;">{{verification_code}}</p>
+<p>This code expires in <strong>{{expires_in_minutes}}</strong> minutes.</p>
+<p>If you did not request this code, please ignore this email.</p>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[{{site_name}}] 邮箱验证码",
+			HTML: notificationEmailCard("#4f46e5", "邮箱验证码", `
+<p>{{recipient_name}}，您好：</p>
+<p>您的验证码是：</p>
+<p style="font-size: 32px; font-weight: 700; letter-spacing: 8px; text-align: center;">{{verification_code}}</p>
+<p>验证码将在 <strong>{{expires_in_minutes}}</strong> 分钟后失效。</p>
+<p>如果不是您本人操作，请忽略此邮件。</p>`),
+		},
+	},
+	NotificationEmailEventAuthPasswordReset: {
+		notificationEmailDefaultLocale: {
+			Subject: "[{{site_name}}] Password reset request",
+			HTML: notificationEmailCard("#7c3aed", "Password reset", `
+<p>Hello {{recipient_name}},</p>
+<p>We received a request to reset your password. Click the button below to set a new password.</p>
+<p><a class="button" href="{{reset_url}}">Reset password</a></p>
+<p>This link expires in <strong>{{expires_in_minutes}}</strong> minutes.</p>
+<p class="muted">If the button does not work, copy this link into your browser:<br>{{reset_url}}</p>
+<p>If you did not request this, you can safely ignore this email.</p>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[{{site_name}}] 密码重置请求",
+			HTML: notificationEmailCard("#7c3aed", "密码重置", `
+<p>{{recipient_name}}，您好：</p>
+<p>我们收到了您的密码重置请求，请点击下方按钮设置新密码。</p>
+<p><a class="button" href="{{reset_url}}">重置密码</a></p>
+<p>此链接将在 <strong>{{expires_in_minutes}}</strong> 分钟后失效。</p>
+<p class="muted">如果按钮无法点击，请复制以下链接到浏览器中打开：<br>{{reset_url}}</p>
+<p>如果不是您本人操作，请忽略此邮件。</p>`),
+		},
+	},
+	NotificationEmailEventNotificationEmailVerifyCode: {
+		notificationEmailDefaultLocale: {
+			Subject: "[{{site_name}}] Notification email verification code",
+			HTML: notificationEmailCard("#0ea5e9", "Notification email verification", `
+<p>Hello {{recipient_name}},</p>
+<p>You are adding this address as an extra notification email.</p>
+<p>Your verification code is:</p>
+<p style="font-size: 32px; font-weight: 700; letter-spacing: 8px; text-align: center;">{{verification_code}}</p>
+<p>This code expires in <strong>{{expires_in_minutes}}</strong> minutes.</p>
+<p>If you did not request this code, please ignore this email.</p>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[{{site_name}}] 通知邮箱验证码",
+			HTML: notificationEmailCard("#0ea5e9", "通知邮箱验证", `
+<p>{{recipient_name}}，您好：</p>
+<p>您正在添加额外的通知邮箱，请输入以下验证码完成验证。</p>
+<p style="font-size: 32px; font-weight: 700; letter-spacing: 8px; text-align: center;">{{verification_code}}</p>
+<p>验证码将在 <strong>{{expires_in_minutes}}</strong> 分钟后失效。</p>
+<p>如果不是您本人操作，请忽略此邮件。</p>`),
+		},
+	},
 	NotificationEmailEventSubscriptionPurchaseSuccess: {
 		notificationEmailDefaultLocale: {
 			Subject: "[{{site_name}}] Subscription purchase successful",
@@ -858,7 +1156,131 @@ var notificationEmailOfficialTemplates = map[string]map[string]notificationEmail
 <p>{{recipient_name}}，您好：</p>
 <p>您的余额充值 <strong>${{recharge_amount}}</strong> 已完成。</p>
 <p>当前余额：<strong>${{current_balance}}</strong></p>
-<p>订单号：{{order_id}}</p>`),
+			<p>订单号：{{order_id}}</p>`),
+		},
+	},
+	NotificationEmailEventAccountQuotaAlert: {
+		notificationEmailDefaultLocale: {
+			Subject: "[{{site_name}}] Account quota alert - {{account_name}}",
+			HTML: notificationEmailCard("#dc2626", "Account quota alert", `
+<p>The upstream account <strong>{{account_name}}</strong> has crossed its configured quota alert threshold.</p>
+<table style="width:100%;border-collapse:collapse;">
+  <tr><td>Account ID</td><td>{{account_id}}</td></tr>
+  <tr><td>Platform</td><td>{{platform}}</td></tr>
+  <tr><td>Dimension</td><td>{{quota_dimension}}</td></tr>
+  <tr><td>Used / Limit</td><td>{{quota_used}} / {{quota_limit}}</td></tr>
+  <tr><td>Remaining</td><td>{{quota_remaining}}</td></tr>
+  <tr><td>Threshold</td><td>{{quota_threshold}}</td></tr>
+</table>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[{{site_name}}] 账号限额告警 - {{account_name}}",
+			HTML: notificationEmailCard("#dc2626", "账号限额告警", `
+<p>上游账号 <strong>{{account_name}}</strong> 已触发配置的额度告警阈值。</p>
+<table style="width:100%;border-collapse:collapse;">
+  <tr><td>账号 ID</td><td>{{account_id}}</td></tr>
+  <tr><td>平台</td><td>{{platform}}</td></tr>
+  <tr><td>维度</td><td>{{quota_dimension}}</td></tr>
+  <tr><td>已用 / 限额</td><td>{{quota_used}} / {{quota_limit}}</td></tr>
+  <tr><td>剩余额度</td><td>{{quota_remaining}}</td></tr>
+  <tr><td>告警阈值</td><td>{{quota_threshold}}</td></tr>
+</table>`),
+		},
+	},
+	NotificationEmailEventContentModerationViolation: {
+		notificationEmailDefaultLocale: {
+			Subject: "[{{site_name}}] Risk control notice",
+			HTML: notificationEmailCard("#ef4444", "Risk control notice", `
+<p>Hello {{recipient_name}},</p>
+<p>Your API request triggered the platform content moderation/risk-control policy.</p>
+<table style="width:100%;border-collapse:collapse;">
+  <tr><td>Triggered at</td><td>{{triggered_at}}</td></tr>
+  <tr><td>Group</td><td>{{group_name}}</td></tr>
+  <tr><td>Category / Score</td><td>{{moderation_category}} / {{moderation_score}}</td></tr>
+  <tr><td>Violation count</td><td>{{violation_count}} / {{ban_threshold}}</td></tr>
+</table>
+<p>Please review your request content to avoid future service interruptions.</p>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[{{site_name}}] 账户风控提醒",
+			HTML: notificationEmailCard("#ef4444", "账户风控提醒", `
+<p>{{recipient_name}}，您好：</p>
+<p>您的 API 请求触发了平台内容审核/风控策略。</p>
+<table style="width:100%;border-collapse:collapse;">
+  <tr><td>触发时间</td><td>{{triggered_at}}</td></tr>
+  <tr><td>所属分组</td><td>{{group_name}}</td></tr>
+  <tr><td>命中类别 / 分数</td><td>{{moderation_category}} / {{moderation_score}}</td></tr>
+  <tr><td>累计触发次数</td><td>{{violation_count}} / {{ban_threshold}}</td></tr>
+</table>
+<p>请检查请求内容，避免后续服务受到影响。</p>`),
+		},
+	},
+	NotificationEmailEventContentModerationDisabled: {
+		notificationEmailDefaultLocale: {
+			Subject: "[{{site_name}}] Account disabled by risk control",
+			HTML: notificationEmailCard("#b91c1c", "Account disabled", `
+<p>Hello {{recipient_name}},</p>
+<p>Your account has repeatedly triggered platform content moderation/risk-control rules and has been automatically disabled.</p>
+<table style="width:100%;border-collapse:collapse;">
+  <tr><td>Disabled at</td><td>{{triggered_at}}</td></tr>
+  <tr><td>Group</td><td>{{group_name}}</td></tr>
+  <tr><td>Category / Score</td><td>{{moderation_category}} / {{moderation_score}}</td></tr>
+  <tr><td>Violation count</td><td>{{violation_count}} / {{ban_threshold}}</td></tr>
+</table>
+<p>Please contact the administrator if you need to appeal or restore access.</p>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[{{site_name}}] 账户已被禁用",
+			HTML: notificationEmailCard("#b91c1c", "账户已被禁用", `
+<p>{{recipient_name}}，您好：</p>
+<p>您的账户在统计周期内多次触发平台内容审核/风控规则，系统已自动禁用该账户。</p>
+<table style="width:100%;border-collapse:collapse;">
+  <tr><td>禁用时间</td><td>{{triggered_at}}</td></tr>
+  <tr><td>所属分组</td><td>{{group_name}}</td></tr>
+  <tr><td>命中类别 / 分数</td><td>{{moderation_category}} / {{moderation_score}}</td></tr>
+  <tr><td>累计触发次数</td><td>{{violation_count}} / {{ban_threshold}}</td></tr>
+</table>
+<p>如需申诉或恢复账号，请联系平台管理员处理。</p>`),
+		},
+	},
+	NotificationEmailEventOpsAlert: {
+		notificationEmailDefaultLocale: {
+			Subject: "[Ops Alert][{{severity}}] {{rule_name}}",
+			HTML: notificationEmailCard("#ea580c", "Ops alert", `
+<p><strong>Rule</strong>: {{rule_name}}</p>
+<p><strong>Severity</strong>: {{severity}}</p>
+<p><strong>Status</strong>: {{alert_status}}</p>
+<p><strong>Metric</strong>: {{metric_type}} {{operator}} {{metric_value}} (threshold {{threshold_value}})</p>
+<p><strong>Fired at</strong>: {{triggered_at}}</p>
+<p><strong>Description</strong>: {{alert_description}}</p>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[运维告警][{{severity}}] {{rule_name}}",
+			HTML: notificationEmailCard("#ea580c", "运维告警", `
+<p><strong>规则</strong>：{{rule_name}}</p>
+<p><strong>严重级别</strong>：{{severity}}</p>
+<p><strong>状态</strong>：{{alert_status}}</p>
+<p><strong>指标</strong>：{{metric_type}} {{operator}} {{metric_value}}（阈值 {{threshold_value}}）</p>
+<p><strong>触发时间</strong>：{{triggered_at}}</p>
+<p><strong>说明</strong>：{{alert_description}}</p>`),
+		},
+	},
+	NotificationEmailEventOpsScheduledReport: {
+		notificationEmailDefaultLocale: {
+			Subject: "[Ops Report] {{report_name}}",
+			HTML: notificationEmailCard("#0891b2", "Ops report", `
+<p><strong>Report</strong>: {{report_name}}</p>
+<p><strong>Type</strong>: {{report_type}}</p>
+<p><strong>Range</strong>: {{report_start_time}} - {{report_end_time}}</p>
+<div>{{report_html}}</div>`),
+		},
+		notificationEmailLocaleChinese: {
+			Subject: "[运维报表] {{report_name}}",
+			HTML: notificationEmailCard("#0891b2", "运维报表", `
+<p><strong>报表</strong>：{{report_name}}</p>
+<p><strong>类型</strong>：{{report_type}}</p>
+<p><strong>时间范围</strong>：{{report_start_time}} - {{report_end_time}}</p>
+<div>{{report_html}}</div>`),
 		},
 	},
 }
diff --git a/backend/internal/service/notification_email_service_test.go b/backend/internal/service/notification_email_service_test.go
index 692b68ef..f375ba7e 100644
--- a/backend/internal/service/notification_email_service_test.go
+++ b/backend/internal/service/notification_email_service_test.go
@@ -2,6 +2,7 @@ package service
 
 import (
 	"context"
+	"errors"
 	"strings"
 	"sync"
 	"testing"
@@ -77,6 +78,154 @@ func TestNotificationEmailTemplateRejectsUnsupportedPlaceholder(t *testing.T) {
 	require.Contains(t, err.Error(), "unsupported placeholder")
 }
 
+func TestNotificationEmailAuthTemplatesAreListedAndPreviewable(t *testing.T) {
+	ctx := context.Background()
+	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)
+
+	infos := svc.ListEventInfos()
+	events := make(map[string]NotificationEmailEventInfo, len(infos))
+	for _, info := range infos {
+		events[info.Event] = info
+	}
+	require.Contains(t, events, NotificationEmailEventAuthVerifyCode)
+	require.Contains(t, events, NotificationEmailEventAuthPasswordReset)
+	require.False(t, events[NotificationEmailEventAuthVerifyCode].Optional)
+	require.False(t, events[NotificationEmailEventAuthPasswordReset].Optional)
+	require.Contains(t, events[NotificationEmailEventAuthVerifyCode].Placeholders, "verification_code")
+	require.Contains(t, events[NotificationEmailEventAuthPasswordReset].Placeholders, "reset_url")
+
+	verifyPreview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{
+		Event:  NotificationEmailEventAuthVerifyCode,
+		Locale: "zh-CN",
+		Variables: map[string]string{
+			"verification_code":  "654321",
+			"expires_in_minutes": "15",
+		},
+	})
+	require.NoError(t, err)
+	require.Contains(t, verifyPreview.Subject, "邮箱验证码")
+	require.Contains(t, verifyPreview.HTML, "654321")
+
+	resetPreview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{
+		Event:  NotificationEmailEventAuthPasswordReset,
+		Locale: "en",
+		Variables: map[string]string{
+			"reset_url":          "https://example.com/reset?token=abc",
+			"expires_in_minutes": "30",
+		},
+	})
+	require.NoError(t, err)
+	require.Contains(t, resetPreview.Subject, "Password reset")
+	require.Contains(t, resetPreview.HTML, "https://example.com/reset?token=abc")
+}
+
+func TestNotificationEmailAdditionalEventsAreListedAndPreviewable(t *testing.T) {
+	ctx := context.Background()
+	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)
+
+	infos := svc.ListEventInfos()
+	events := make(map[string]NotificationEmailEventInfo, len(infos))
+	for _, info := range infos {
+		events[info.Event] = info
+	}
+
+	checks := []struct {
+		event       string
+		placeholder string
+	}{
+		{NotificationEmailEventNotificationEmailVerifyCode, "verification_code"},
+		{NotificationEmailEventAccountQuotaAlert, "account_name"},
+		{NotificationEmailEventContentModerationViolation, "moderation_category"},
+		{NotificationEmailEventContentModerationDisabled, "violation_count"},
+		{NotificationEmailEventOpsAlert, "rule_name"},
+		{NotificationEmailEventOpsScheduledReport, "report_html"},
+	}
+
+	for _, check := range checks {
+		info, ok := events[check.event]
+		require.Truef(t, ok, "expected %s to be listed", check.event)
+		require.False(t, info.Optional)
+		require.Contains(t, info.Placeholders, check.placeholder)
+
+		preview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{Event: check.event, Locale: "zh"})
+		require.NoError(t, err)
+		require.NotEmpty(t, preview.Subject)
+		require.NotEmpty(t, preview.HTML)
+	}
+}
+
+func TestNotificationEmailRawHTMLVariablesAreTrustedOnlyForHTMLPlaceholders(t *testing.T) {
+	require.True(t, notificationEmailRawHTMLAllowed(NotificationEmailEventOpsScheduledReport, "report_html"))
+	require.False(t, notificationEmailRawHTMLAllowed(NotificationEmailEventOpsScheduledReport, "recipient_name"))
+	require.False(t, notificationEmailRawHTMLAllowed(NotificationEmailEventOpsAlert, "report_html"))
+
+	preview, err := renderNotificationEmail(
+		NotificationEmailEventOpsScheduledReport,
+		"Report for {{recipient_name}}",
+		`<section>{{report_html}}</section><p>{{recipient_name}}</p>`,
+		map[string]string{
+			"recipient_name": `<script>alert("x")</script>`,
+			"report_html":    `<p>escaped report</p>`,
+		},
+		map[string]string{
+			"report_html": `<table><tr><td>trusted report</td></tr></table>`,
+		},
+	)
+	require.NoError(t, err)
+	require.Contains(t, preview.HTML, `<table><tr><td>trusted report</td></tr></table>`)
+	require.NotContains(t, preview.HTML, `escaped report`)
+	require.Contains(t, preview.HTML, `&lt;script&gt;alert(&#34;x&#34;)&lt;/script&gt;`)
+	require.Contains(t, preview.Subject, `<script>alert("x")</script>`)
+
+	preview, err = renderNotificationEmail(
+		NotificationEmailEventOpsScheduledReport,
+		"Recipient {{recipient_name}}",
+		`<p>{{recipient_name}}</p>`,
+		map[string]string{"recipient_name": `<em>escaped</em>`},
+		map[string]string{"recipient_name": `<strong>raw</strong>`},
+	)
+	require.NoError(t, err)
+	require.Contains(t, preview.HTML, `&lt;em&gt;escaped&lt;/em&gt;`)
+	require.NotContains(t, preview.HTML, `<strong>raw</strong>`)
+}
+
+func TestNotificationEmailFallbackClassification(t *testing.T) {
+	templateErr := notificationEmailTemplateErr(errors.New("bad template"))
+	configErr := notificationEmailConfigErr(errors.New("missing email service"))
+	deliveryErr := notificationEmailDeliveryErr(errors.New("smtp timeout"))
+
+	require.True(t, shouldFallbackNotificationEmail(templateErr))
+	require.True(t, shouldFallbackNotificationEmail(configErr))
+	require.False(t, shouldFallbackNotificationEmail(deliveryErr))
+	require.True(t, isNotificationEmailDeliveryError(deliveryErr))
+	require.False(t, isNotificationEmailDeliveryError(templateErr))
+	require.False(t, shouldFallbackNotificationEmail(nil))
+}
+
+func TestEmailQueueTasksPreserveLocaleHints(t *testing.T) {
+	queue := &EmailQueueService{taskChan: make(chan EmailTask, 2)}
+	require.NoError(t, queue.EnqueueVerifyCode("user@example.com", "Sub2API", "zh-CN"))
+	require.NoError(t, queue.EnqueuePasswordReset("user@example.com", "Sub2API", "https://example.com/reset", "en-US"))
+
+	verifyTask := <-queue.taskChan
+	require.Equal(t, TaskTypeVerifyCode, verifyTask.TaskType)
+	require.Equal(t, "zh-CN", verifyTask.Locale)
+
+	resetTask := <-queue.taskChan
+	require.Equal(t, TaskTypePasswordReset, resetTask.TaskType)
+	require.Equal(t, "en-US", resetTask.Locale)
+}
+
+func TestOpsScheduledReportDeliverySourceIDIncludesReportIdentity(t *testing.T) {
+	report := &opsScheduledReport{Name: "日报", ReportType: "daily_summary", Schedule: "0 9 * * *"}
+	sourceID := opsScheduledReportDeliverySourceID(report)
+	require.Contains(t, sourceID, "daily_summary")
+	require.Contains(t, sourceID, "日报")
+	require.Contains(t, sourceID, "0 9 * * *")
+	require.NotEqual(t, sourceID, opsScheduledReportDeliverySourceID(&opsScheduledReport{Name: "周报", ReportType: "weekly_summary", Schedule: "0 9 * * 1"}))
+	require.Equal(t, "scheduled_report", opsScheduledReportDeliverySourceID(nil))
+}
+
 func TestNotificationEmailUnsubscribeOnlyAllowsOptionalEvents(t *testing.T) {
 	ctx := context.Background()
 	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)
@@ -96,6 +245,12 @@ func TestNotificationEmailUnsubscribeOnlyAllowsOptionalEvents(t *testing.T) {
 	_, err = svc.Unsubscribe(ctx, transactionalToken)
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "transactional")
+
+	authToken, err := svc.createUnsubscribeToken(ctx, "user@example.com", NotificationEmailEventAuthVerifyCode)
+	require.NoError(t, err)
+	_, err = svc.Unsubscribe(ctx, authToken)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "transactional")
 }
 
 func TestNotificationEmailLocaleMemoryNormalizesAcceptLanguage(t *testing.T) {