diff --git a/backend/cmd/server/wire_gen.go b/backend/cmd/server/wire_gen.go
index 289a14bd..27404b02 100644
--- a/backend/cmd/server/wire_gen.go
+++ b/backend/cmd/server/wire_gen.go
@@ -78,7 +78,10 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	dashboardAggregationRepository := repository.NewDashboardAggregationRepository(db)
 	dashboardStatsCache := repository.NewDashboardCache(redisClient, configConfig)
 	dashboardService := service.NewDashboardService(usageLogRepository, dashboardAggregationRepository, dashboardStatsCache, configConfig)
-	timingWheelService := service.ProvideTimingWheelService()
+	timingWheelService, err := service.ProvideTimingWheelService()
+	if err != nil {
+		return nil, err
+	}
 	dashboardAggregationService := service.ProvideDashboardAggregationService(dashboardAggregationRepository, timingWheelService, configConfig)
 	dashboardHandler := admin.NewDashboardHandler(dashboardService, dashboardAggregationService)
 	accountRepository := repository.NewAccountRepository(client, db)
diff --git a/backend/internal/config/config.go b/backend/internal/config/config.go
index 944e0f84..5dc6ad19 100644
--- a/backend/internal/config/config.go
+++ b/backend/internal/config/config.go
@@ -19,7 +19,9 @@ const (
 	RunModeSimple   = "simple"
 )
 
-const DefaultCSPPolicy = "default-src 'self'; script-src 'self' https://challenges.cloudflare.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; img-src 'self' data: https:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https:; frame-src https://challenges.cloudflare.com; frame-ancestors 'none'; base-uri 'self'; form-action 'self'"
+// DefaultCSPPolicy is the default Content-Security-Policy with nonce support
+// __CSP_NONCE__ will be replaced with actual nonce at request time by the SecurityHeaders middleware
+const DefaultCSPPolicy = "default-src 'self'; script-src 'self' __CSP_NONCE__ https://challenges.cloudflare.com https://static.cloudflareinsights.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; img-src 'self' data: https:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https:; frame-src https://challenges.cloudflare.com; frame-ancestors 'none'; base-uri 'self'; form-action 'self'"
 
 // 连接池隔离策略常量
 // 用于控制上游 HTTP 连接池的隔离粒度，影响连接复用和资源消耗
diff --git a/backend/internal/server/middleware/security_headers.go b/backend/internal/server/middleware/security_headers.go
index 9fca0cd3..9ce7f449 100644
--- a/backend/internal/server/middleware/security_headers.go
+++ b/backend/internal/server/middleware/security_headers.go
@@ -1,12 +1,40 @@
 package middleware
 
 import (
+	"crypto/rand"
+	"encoding/base64"
 	"strings"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/gin-gonic/gin"
 )
 
+const (
+	// CSPNonceKey is the context key for storing the CSP nonce
+	CSPNonceKey = "csp_nonce"
+	// NonceTemplate is the placeholder in CSP policy for nonce
+	NonceTemplate = "__CSP_NONCE__"
+	// CloudflareInsightsDomain is the domain for Cloudflare Web Analytics
+	CloudflareInsightsDomain = "https://static.cloudflareinsights.com"
+)
+
+// GenerateNonce generates a cryptographically secure random nonce
+func GenerateNonce() string {
+	b := make([]byte, 16)
+	_, _ = rand.Read(b)
+	return base64.StdEncoding.EncodeToString(b)
+}
+
+// GetNonceFromContext retrieves the CSP nonce from gin context
+func GetNonceFromContext(c *gin.Context) string {
+	if nonce, exists := c.Get(CSPNonceKey); exists {
+		if s, ok := nonce.(string); ok {
+			return s
+		}
+	}
+	return ""
+}
+
 // SecurityHeaders sets baseline security headers for all responses.
 func SecurityHeaders(cfg config.CSPConfig) gin.HandlerFunc {
 	policy := strings.TrimSpace(cfg.Policy)
@@ -14,13 +42,75 @@ func SecurityHeaders(cfg config.CSPConfig) gin.HandlerFunc {
 		policy = config.DefaultCSPPolicy
 	}
 
+	// Enhance policy with required directives (nonce placeholder and Cloudflare Insights)
+	policy = enhanceCSPPolicy(policy)
+
 	return func(c *gin.Context) {
 		c.Header("X-Content-Type-Options", "nosniff")
 		c.Header("X-Frame-Options", "DENY")
 		c.Header("Referrer-Policy", "strict-origin-when-cross-origin")
+
 		if cfg.Enabled {
-			c.Header("Content-Security-Policy", policy)
+			// Generate nonce for this request
+			nonce := GenerateNonce()
+			c.Set(CSPNonceKey, nonce)
+
+			// Replace nonce placeholder in policy
+			finalPolicy := strings.ReplaceAll(policy, NonceTemplate, "'nonce-"+nonce+"'")
+			c.Header("Content-Security-Policy", finalPolicy)
 		}
 		c.Next()
 	}
 }
+
+// enhanceCSPPolicy ensures the CSP policy includes nonce support and Cloudflare Insights domain.
+// This allows the application to work correctly even if the config file has an older CSP policy.
+func enhanceCSPPolicy(policy string) string {
+	// Add nonce placeholder to script-src if not present
+	if !strings.Contains(policy, NonceTemplate) && !strings.Contains(policy, "'nonce-") {
+		policy = addToDirective(policy, "script-src", NonceTemplate)
+	}
+
+	// Add Cloudflare Insights domain to script-src if not present
+	if !strings.Contains(policy, CloudflareInsightsDomain) {
+		policy = addToDirective(policy, "script-src", CloudflareInsightsDomain)
+	}
+
+	return policy
+}
+
+// addToDirective adds a value to a specific CSP directive.
+// If the directive doesn't exist, it will be added after default-src.
+func addToDirective(policy, directive, value string) string {
+	// Find the directive in the policy
+	directivePrefix := directive + " "
+	idx := strings.Index(policy, directivePrefix)
+
+	if idx == -1 {
+		// Directive not found, add it after default-src or at the beginning
+		defaultSrcIdx := strings.Index(policy, "default-src ")
+		if defaultSrcIdx != -1 {
+			// Find the end of default-src directive (next semicolon)
+			endIdx := strings.Index(policy[defaultSrcIdx:], ";")
+			if endIdx != -1 {
+				insertPos := defaultSrcIdx + endIdx + 1
+				// Insert new directive after default-src
+				return policy[:insertPos] + " " + directive + " 'self' " + value + ";" + policy[insertPos:]
+			}
+		}
+		// Fallback: prepend the directive
+		return directive + " 'self' " + value + "; " + policy
+	}
+
+	// Find the end of this directive (next semicolon or end of string)
+	endIdx := strings.Index(policy[idx:], ";")
+
+	if endIdx == -1 {
+		// No semicolon found, directive goes to end of string
+		return policy + " " + value
+	}
+
+	// Insert value before the semicolon
+	insertPos := idx + endIdx
+	return policy[:insertPos] + " " + value + policy[insertPos:]
+}
diff --git a/backend/internal/server/middleware/security_headers_test.go b/backend/internal/server/middleware/security_headers_test.go
new file mode 100644
index 00000000..dc7a87d8
--- /dev/null
+++ b/backend/internal/server/middleware/security_headers_test.go
@@ -0,0 +1,365 @@
+package middleware
+
+import (
+	"encoding/base64"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func init() {
+	gin.SetMode(gin.TestMode)
+}
+
+func TestGenerateNonce(t *testing.T) {
+	t.Run("generates_valid_base64_string", func(t *testing.T) {
+		nonce := GenerateNonce()
+
+		// Should be valid base64
+		decoded, err := base64.StdEncoding.DecodeString(nonce)
+		require.NoError(t, err)
+
+		// Should decode to 16 bytes
+		assert.Len(t, decoded, 16)
+	})
+
+	t.Run("generates_unique_nonces", func(t *testing.T) {
+		nonces := make(map[string]bool)
+		for i := 0; i < 100; i++ {
+			nonce := GenerateNonce()
+			assert.False(t, nonces[nonce], "nonce should be unique")
+			nonces[nonce] = true
+		}
+	})
+
+	t.Run("nonce_has_expected_length", func(t *testing.T) {
+		nonce := GenerateNonce()
+		// 16 bytes -> 24 chars in base64 (with padding)
+		assert.Len(t, nonce, 24)
+	})
+}
+
+func TestGetNonceFromContext(t *testing.T) {
+	t.Run("returns_nonce_when_present", func(t *testing.T) {
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+
+		expectedNonce := "test-nonce-123"
+		c.Set(CSPNonceKey, expectedNonce)
+
+		nonce := GetNonceFromContext(c)
+		assert.Equal(t, expectedNonce, nonce)
+	})
+
+	t.Run("returns_empty_string_when_not_present", func(t *testing.T) {
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+
+		nonce := GetNonceFromContext(c)
+		assert.Empty(t, nonce)
+	})
+
+	t.Run("returns_empty_for_wrong_type", func(t *testing.T) {
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+
+		// Set a non-string value
+		c.Set(CSPNonceKey, 12345)
+
+		// Should return empty string for wrong type (safe type assertion)
+		nonce := GetNonceFromContext(c)
+		assert.Empty(t, nonce)
+	})
+}
+
+func TestSecurityHeaders(t *testing.T) {
+	t.Run("sets_basic_security_headers", func(t *testing.T) {
+		cfg := config.CSPConfig{Enabled: false}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		assert.Equal(t, "nosniff", w.Header().Get("X-Content-Type-Options"))
+		assert.Equal(t, "DENY", w.Header().Get("X-Frame-Options"))
+		assert.Equal(t, "strict-origin-when-cross-origin", w.Header().Get("Referrer-Policy"))
+	})
+
+	t.Run("csp_disabled_no_csp_header", func(t *testing.T) {
+		cfg := config.CSPConfig{Enabled: false}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		assert.Empty(t, w.Header().Get("Content-Security-Policy"))
+	})
+
+	t.Run("csp_enabled_sets_csp_header", func(t *testing.T) {
+		cfg := config.CSPConfig{
+			Enabled: true,
+			Policy:  "default-src 'self'",
+		}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		csp := w.Header().Get("Content-Security-Policy")
+		assert.NotEmpty(t, csp)
+		// Policy is auto-enhanced with nonce and Cloudflare Insights domain
+		assert.Contains(t, csp, "default-src 'self'")
+		assert.Contains(t, csp, "'nonce-")
+		assert.Contains(t, csp, CloudflareInsightsDomain)
+	})
+
+	t.Run("csp_enabled_with_nonce_placeholder", func(t *testing.T) {
+		cfg := config.CSPConfig{
+			Enabled: true,
+			Policy:  "script-src 'self' __CSP_NONCE__",
+		}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		csp := w.Header().Get("Content-Security-Policy")
+		assert.NotEmpty(t, csp)
+		assert.NotContains(t, csp, "__CSP_NONCE__", "placeholder should be replaced")
+		assert.Contains(t, csp, "'nonce-", "should contain nonce directive")
+
+		// Verify nonce is stored in context
+		nonce := GetNonceFromContext(c)
+		assert.NotEmpty(t, nonce)
+		assert.Contains(t, csp, "'nonce-"+nonce+"'")
+	})
+
+	t.Run("uses_default_policy_when_empty", func(t *testing.T) {
+		cfg := config.CSPConfig{
+			Enabled: true,
+			Policy:  "",
+		}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		csp := w.Header().Get("Content-Security-Policy")
+		assert.NotEmpty(t, csp)
+		// Default policy should contain these elements
+		assert.Contains(t, csp, "default-src 'self'")
+	})
+
+	t.Run("uses_default_policy_when_whitespace_only", func(t *testing.T) {
+		cfg := config.CSPConfig{
+			Enabled: true,
+			Policy:  "   \t\n  ",
+		}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		csp := w.Header().Get("Content-Security-Policy")
+		assert.NotEmpty(t, csp)
+		assert.Contains(t, csp, "default-src 'self'")
+	})
+
+	t.Run("multiple_nonce_placeholders_replaced", func(t *testing.T) {
+		cfg := config.CSPConfig{
+			Enabled: true,
+			Policy:  "script-src __CSP_NONCE__; style-src __CSP_NONCE__",
+		}
+		middleware := SecurityHeaders(cfg)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		middleware(c)
+
+		csp := w.Header().Get("Content-Security-Policy")
+		nonce := GetNonceFromContext(c)
+
+		// Count occurrences of the nonce
+		count := strings.Count(csp, "'nonce-"+nonce+"'")
+		assert.Equal(t, 2, count, "both placeholders should be replaced with same nonce")
+	})
+
+	t.Run("calls_next_handler", func(t *testing.T) {
+		cfg := config.CSPConfig{Enabled: true, Policy: "default-src 'self'"}
+		middleware := SecurityHeaders(cfg)
+
+		nextCalled := false
+		router := gin.New()
+		router.Use(middleware)
+		router.GET("/test", func(c *gin.Context) {
+			nextCalled = true
+			c.Status(http.StatusOK)
+		})
+
+		w := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/test", nil)
+		router.ServeHTTP(w, req)
+
+		assert.True(t, nextCalled, "next handler should be called")
+		assert.Equal(t, http.StatusOK, w.Code)
+	})
+
+	t.Run("nonce_unique_per_request", func(t *testing.T) {
+		cfg := config.CSPConfig{
+			Enabled: true,
+			Policy:  "script-src __CSP_NONCE__",
+		}
+		middleware := SecurityHeaders(cfg)
+
+		nonces := make(map[string]bool)
+		for i := 0; i < 10; i++ {
+			w := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(w)
+			c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+			middleware(c)
+
+			nonce := GetNonceFromContext(c)
+			assert.False(t, nonces[nonce], "nonce should be unique per request")
+			nonces[nonce] = true
+		}
+	})
+}
+
+func TestCSPNonceKey(t *testing.T) {
+	t.Run("constant_value", func(t *testing.T) {
+		assert.Equal(t, "csp_nonce", CSPNonceKey)
+	})
+}
+
+func TestNonceTemplate(t *testing.T) {
+	t.Run("constant_value", func(t *testing.T) {
+		assert.Equal(t, "__CSP_NONCE__", NonceTemplate)
+	})
+}
+
+func TestEnhanceCSPPolicy(t *testing.T) {
+	t.Run("adds_nonce_placeholder_if_missing", func(t *testing.T) {
+		policy := "default-src 'self'; script-src 'self'"
+		enhanced := enhanceCSPPolicy(policy)
+
+		assert.Contains(t, enhanced, NonceTemplate)
+		assert.Contains(t, enhanced, CloudflareInsightsDomain)
+	})
+
+	t.Run("does_not_duplicate_nonce_placeholder", func(t *testing.T) {
+		policy := "default-src 'self'; script-src 'self' __CSP_NONCE__"
+		enhanced := enhanceCSPPolicy(policy)
+
+		// Should not duplicate
+		count := strings.Count(enhanced, NonceTemplate)
+		assert.Equal(t, 1, count)
+	})
+
+	t.Run("does_not_duplicate_cloudflare_domain", func(t *testing.T) {
+		policy := "default-src 'self'; script-src 'self' https://static.cloudflareinsights.com"
+		enhanced := enhanceCSPPolicy(policy)
+
+		count := strings.Count(enhanced, CloudflareInsightsDomain)
+		assert.Equal(t, 1, count)
+	})
+
+	t.Run("handles_policy_without_script_src", func(t *testing.T) {
+		policy := "default-src 'self'"
+		enhanced := enhanceCSPPolicy(policy)
+
+		assert.Contains(t, enhanced, "script-src")
+		assert.Contains(t, enhanced, NonceTemplate)
+		assert.Contains(t, enhanced, CloudflareInsightsDomain)
+	})
+
+	t.Run("preserves_existing_nonce", func(t *testing.T) {
+		policy := "script-src 'self' 'nonce-existing'"
+		enhanced := enhanceCSPPolicy(policy)
+
+		// Should not add placeholder if nonce already exists
+		assert.NotContains(t, enhanced, NonceTemplate)
+		assert.Contains(t, enhanced, "'nonce-existing'")
+	})
+}
+
+func TestAddToDirective(t *testing.T) {
+	t.Run("adds_to_existing_directive", func(t *testing.T) {
+		policy := "script-src 'self'; style-src 'self'"
+		result := addToDirective(policy, "script-src", "https://example.com")
+
+		assert.Contains(t, result, "script-src 'self' https://example.com")
+	})
+
+	t.Run("creates_directive_if_not_exists", func(t *testing.T) {
+		policy := "default-src 'self'"
+		result := addToDirective(policy, "script-src", "https://example.com")
+
+		assert.Contains(t, result, "script-src")
+		assert.Contains(t, result, "https://example.com")
+	})
+
+	t.Run("handles_directive_at_end_without_semicolon", func(t *testing.T) {
+		policy := "default-src 'self'; script-src 'self'"
+		result := addToDirective(policy, "script-src", "https://example.com")
+
+		assert.Contains(t, result, "https://example.com")
+	})
+
+	t.Run("handles_empty_policy", func(t *testing.T) {
+		policy := ""
+		result := addToDirective(policy, "script-src", "https://example.com")
+
+		assert.Contains(t, result, "script-src")
+		assert.Contains(t, result, "https://example.com")
+	})
+}
+
+// Benchmark tests
+func BenchmarkGenerateNonce(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		GenerateNonce()
+	}
+}
+
+func BenchmarkSecurityHeadersMiddleware(b *testing.B) {
+	cfg := config.CSPConfig{
+		Enabled: true,
+		Policy:  "script-src 'self' __CSP_NONCE__",
+	}
+	middleware := SecurityHeaders(cfg)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		middleware(c)
+	}
+}
diff --git a/backend/internal/service/timing_wheel_service.go b/backend/internal/service/timing_wheel_service.go
index c4e64e33..5a2dea75 100644
--- a/backend/internal/service/timing_wheel_service.go
+++ b/backend/internal/service/timing_wheel_service.go
@@ -1,6 +1,7 @@
 package service
 
 import (
+	"fmt"
 	"log"
 	"sync"
 	"time"
@@ -8,6 +9,8 @@ import (
 	"github.com/zeromicro/go-zero/core/collection"
 )
 
+var newTimingWheel = collection.NewTimingWheel
+
 // TimingWheelService wraps go-zero's TimingWheel for task scheduling
 type TimingWheelService struct {
 	tw       *collection.TimingWheel
@@ -15,18 +18,18 @@ type TimingWheelService struct {
 }
 
 // NewTimingWheelService creates a new TimingWheelService instance
-func NewTimingWheelService() *TimingWheelService {
+func NewTimingWheelService() (*TimingWheelService, error) {
 	// 1 second tick, 3600 slots = supports up to 1 hour delay
 	// execute function: runs func() type tasks
-	tw, err := collection.NewTimingWheel(1*time.Second, 3600, func(key, value any) {
+	tw, err := newTimingWheel(1*time.Second, 3600, func(key, value any) {
 		if fn, ok := value.(func()); ok {
 			fn()
 		}
 	})
 	if err != nil {
-		panic(err)
+		return nil, fmt.Errorf("创建 timing wheel 失败: %w", err)
 	}
-	return &TimingWheelService{tw: tw}
+	return &TimingWheelService{tw: tw}, nil
 }
 
 // Start starts the timing wheel
diff --git a/backend/internal/service/timing_wheel_service_test.go b/backend/internal/service/timing_wheel_service_test.go
new file mode 100644
index 00000000..cd0bffb7
--- /dev/null
+++ b/backend/internal/service/timing_wheel_service_test.go
@@ -0,0 +1,146 @@
+package service
+
+import (
+	"errors"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/zeromicro/go-zero/core/collection"
+)
+
+func TestNewTimingWheelService_InitFail_NoPanicAndReturnError(t *testing.T) {
+	original := newTimingWheel
+	t.Cleanup(func() { newTimingWheel = original })
+
+	newTimingWheel = func(_ time.Duration, _ int, _ collection.Execute) (*collection.TimingWheel, error) {
+		return nil, errors.New("boom")
+	}
+
+	svc, err := NewTimingWheelService()
+	if err == nil {
+		t.Fatalf("期望返回 error，但得到 nil")
+	}
+	if svc != nil {
+		t.Fatalf("期望返回 nil svc，但得到非空")
+	}
+}
+
+func TestNewTimingWheelService_Success(t *testing.T) {
+	svc, err := NewTimingWheelService()
+	if err != nil {
+		t.Fatalf("期望 err 为 nil，但得到: %v", err)
+	}
+	if svc == nil {
+		t.Fatalf("期望 svc 非空，但得到 nil")
+	}
+	svc.Stop()
+}
+
+func TestNewTimingWheelService_ExecuteCallbackRunsFunc(t *testing.T) {
+	original := newTimingWheel
+	t.Cleanup(func() { newTimingWheel = original })
+
+	var captured collection.Execute
+	newTimingWheel = func(interval time.Duration, numSlots int, execute collection.Execute) (*collection.TimingWheel, error) {
+		captured = execute
+		return original(interval, numSlots, execute)
+	}
+
+	svc, err := NewTimingWheelService()
+	if err != nil {
+		t.Fatalf("期望 err 为 nil，但得到: %v", err)
+	}
+	if captured == nil {
+		t.Fatalf("期望 captured 非空，但得到 nil")
+	}
+
+	called := false
+	captured("k", func() { called = true })
+	if !called {
+		t.Fatalf("期望 execute 回调触发传入函数执行")
+	}
+
+	svc.Stop()
+}
+
+func TestTimingWheelService_Schedule_ExecutesOnce(t *testing.T) {
+	original := newTimingWheel
+	t.Cleanup(func() { newTimingWheel = original })
+
+	newTimingWheel = func(_ time.Duration, _ int, execute collection.Execute) (*collection.TimingWheel, error) {
+		return original(10*time.Millisecond, 128, execute)
+	}
+
+	svc, err := NewTimingWheelService()
+	if err != nil {
+		t.Fatalf("期望 err 为 nil，但得到: %v", err)
+	}
+	defer svc.Stop()
+
+	ch := make(chan struct{}, 1)
+	svc.Schedule("once", 30*time.Millisecond, func() { ch <- struct{}{} })
+
+	select {
+	case <-ch:
+	case <-time.After(500 * time.Millisecond):
+		t.Fatalf("等待任务执行超时")
+	}
+
+	select {
+	case <-ch:
+		t.Fatalf("任务不应重复执行")
+	case <-time.After(80 * time.Millisecond):
+	}
+}
+
+func TestTimingWheelService_Cancel_PreventsExecution(t *testing.T) {
+	original := newTimingWheel
+	t.Cleanup(func() { newTimingWheel = original })
+
+	newTimingWheel = func(_ time.Duration, _ int, execute collection.Execute) (*collection.TimingWheel, error) {
+		return original(10*time.Millisecond, 128, execute)
+	}
+
+	svc, err := NewTimingWheelService()
+	if err != nil {
+		t.Fatalf("期望 err 为 nil，但得到: %v", err)
+	}
+	defer svc.Stop()
+
+	ch := make(chan struct{}, 1)
+	svc.Schedule("cancel", 80*time.Millisecond, func() { ch <- struct{}{} })
+	svc.Cancel("cancel")
+
+	select {
+	case <-ch:
+		t.Fatalf("任务已取消，不应执行")
+	case <-time.After(200 * time.Millisecond):
+	}
+}
+
+func TestTimingWheelService_ScheduleRecurring_ExecutesMultipleTimes(t *testing.T) {
+	original := newTimingWheel
+	t.Cleanup(func() { newTimingWheel = original })
+
+	newTimingWheel = func(_ time.Duration, _ int, execute collection.Execute) (*collection.TimingWheel, error) {
+		return original(10*time.Millisecond, 128, execute)
+	}
+
+	svc, err := NewTimingWheelService()
+	if err != nil {
+		t.Fatalf("期望 err 为 nil，但得到: %v", err)
+	}
+	defer svc.Stop()
+
+	var count int32
+	svc.ScheduleRecurring("rec", 30*time.Millisecond, func() { atomic.AddInt32(&count, 1) })
+
+	deadline := time.Now().Add(500 * time.Millisecond)
+	for atomic.LoadInt32(&count) < 2 && time.Now().Before(deadline) {
+		time.Sleep(10 * time.Millisecond)
+	}
+	if atomic.LoadInt32(&count) < 2 {
+		t.Fatalf("期望周期任务至少执行 2 次，但只执行了 %d 次", atomic.LoadInt32(&count))
+	}
+}
diff --git a/backend/internal/service/wire.go b/backend/internal/service/wire.go
index 5ba093a4..acc0a5fb 100644
--- a/backend/internal/service/wire.go
+++ b/backend/internal/service/wire.go
@@ -65,10 +65,13 @@ func ProvideAccountExpiryService(accountRepo AccountRepository) *AccountExpirySe
 }
 
 // ProvideTimingWheelService creates and starts TimingWheelService
-func ProvideTimingWheelService() *TimingWheelService {
-	svc := NewTimingWheelService()
+func ProvideTimingWheelService() (*TimingWheelService, error) {
+	svc, err := NewTimingWheelService()
+	if err != nil {
+		return nil, err
+	}
 	svc.Start()
-	return svc
+	return svc, nil
 }
 
 // ProvideDeferredService creates and starts DeferredService
diff --git a/backend/internal/service/wire_test.go b/backend/internal/service/wire_test.go
new file mode 100644
index 00000000..5f7866f6
--- /dev/null
+++ b/backend/internal/service/wire_test.go
@@ -0,0 +1,37 @@
+package service
+
+import (
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/zeromicro/go-zero/core/collection"
+)
+
+func TestProvideTimingWheelService_ReturnsError(t *testing.T) {
+	original := newTimingWheel
+	t.Cleanup(func() { newTimingWheel = original })
+
+	newTimingWheel = func(_ time.Duration, _ int, _ collection.Execute) (*collection.TimingWheel, error) {
+		return nil, errors.New("boom")
+	}
+
+	svc, err := ProvideTimingWheelService()
+	if err == nil {
+		t.Fatalf("期望返回 error，但得到 nil")
+	}
+	if svc != nil {
+		t.Fatalf("期望返回 nil svc，但得到非空")
+	}
+}
+
+func TestProvideTimingWheelService_Success(t *testing.T) {
+	svc, err := ProvideTimingWheelService()
+	if err != nil {
+		t.Fatalf("期望 err 为 nil，但得到: %v", err)
+	}
+	if svc == nil {
+		t.Fatalf("期望 svc 非空，但得到 nil")
+	}
+	svc.Stop()
+}
diff --git a/backend/internal/web/embed_on.go b/backend/internal/web/embed_on.go
index 35697fbb..7f37d59c 100644
--- a/backend/internal/web/embed_on.go
+++ b/backend/internal/web/embed_on.go
@@ -13,9 +13,15 @@ import (
 	"strings"
 	"time"
 
+	"github.com/Wei-Shaw/sub2api/internal/server/middleware"
 	"github.com/gin-gonic/gin"
 )
 
+const (
+	// NonceHTMLPlaceholder is the placeholder for nonce in HTML script tags
+	NonceHTMLPlaceholder = "__CSP_NONCE_VALUE__"
+)
+
 //go:embed all:dist
 var frontendFS embed.FS
 
@@ -115,6 +121,9 @@ func (s *FrontendServer) fileExists(path string) bool {
 }
 
 func (s *FrontendServer) serveIndexHTML(c *gin.Context) {
+	// Get nonce from context (generated by SecurityHeaders middleware)
+	nonce := middleware.GetNonceFromContext(c)
+
 	// Check cache first
 	cached := s.cache.Get()
 	if cached != nil {
@@ -125,9 +134,12 @@ func (s *FrontendServer) serveIndexHTML(c *gin.Context) {
 			return
 		}
 
+		// Replace nonce placeholder with actual nonce before serving
+		content := replaceNoncePlaceholder(cached.Content, nonce)
+
 		c.Header("ETag", cached.ETag)
 		c.Header("Cache-Control", "no-cache") // Must revalidate
-		c.Data(http.StatusOK, "text/html; charset=utf-8", cached.Content)
+		c.Data(http.StatusOK, "text/html; charset=utf-8", content)
 		c.Abort()
 		return
 	}
@@ -155,24 +167,33 @@ func (s *FrontendServer) serveIndexHTML(c *gin.Context) {
 	rendered := s.injectSettings(settingsJSON)
 	s.cache.Set(rendered, settingsJSON)
 
+	// Replace nonce placeholder with actual nonce before serving
+	content := replaceNoncePlaceholder(rendered, nonce)
+
 	cached = s.cache.Get()
 	if cached != nil {
 		c.Header("ETag", cached.ETag)
 	}
 	c.Header("Cache-Control", "no-cache")
-	c.Data(http.StatusOK, "text/html; charset=utf-8", rendered)
+	c.Data(http.StatusOK, "text/html; charset=utf-8", content)
 	c.Abort()
 }
 
 func (s *FrontendServer) injectSettings(settingsJSON []byte) []byte {
-	// Create the script tag to inject
-	script := []byte(`<script>window.__APP_CONFIG__=` + string(settingsJSON) + `;</script>`)
+	// Create the script tag to inject with nonce placeholder
+	// The placeholder will be replaced with actual nonce at request time
+	script := []byte(`<script nonce="` + NonceHTMLPlaceholder + `">window.__APP_CONFIG__=` + string(settingsJSON) + `;</script>`)
 
 	// Inject before </head>
 	headClose := []byte("</head>")
 	return bytes.Replace(s.baseHTML, headClose, append(script, headClose...), 1)
 }
 
+// replaceNoncePlaceholder replaces the nonce placeholder with actual nonce value
+func replaceNoncePlaceholder(html []byte, nonce string) []byte {
+	return bytes.ReplaceAll(html, []byte(NonceHTMLPlaceholder), []byte(nonce))
+}
+
 // ServeEmbeddedFrontend returns a middleware for serving embedded frontend
 // This is the legacy function for backward compatibility when no settings provider is available
 func ServeEmbeddedFrontend() gin.HandlerFunc {
diff --git a/backend/internal/web/embed_test.go b/backend/internal/web/embed_test.go
new file mode 100644
index 00000000..50f5a323
--- /dev/null
+++ b/backend/internal/web/embed_test.go
@@ -0,0 +1,660 @@
+//go:build embed
+
+package web
+
+import (
+	"bytes"
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/server/middleware"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func init() {
+	gin.SetMode(gin.TestMode)
+}
+
+func TestReplaceNoncePlaceholder(t *testing.T) {
+	t.Run("replaces_single_placeholder", func(t *testing.T) {
+		html := []byte(`<script nonce="__CSP_NONCE_VALUE__">console.log('test');</script>`)
+		nonce := "abc123xyz"
+
+		result := replaceNoncePlaceholder(html, nonce)
+
+		expected := `<script nonce="abc123xyz">console.log('test');</script>`
+		assert.Equal(t, expected, string(result))
+	})
+
+	t.Run("replaces_multiple_placeholders", func(t *testing.T) {
+		html := []byte(`<script nonce="__CSP_NONCE_VALUE__">a</script><script nonce="__CSP_NONCE_VALUE__">b</script>`)
+		nonce := "nonce123"
+
+		result := replaceNoncePlaceholder(html, nonce)
+
+		assert.Equal(t, 2, strings.Count(string(result), `nonce="nonce123"`))
+		assert.NotContains(t, string(result), NonceHTMLPlaceholder)
+	})
+
+	t.Run("handles_empty_nonce", func(t *testing.T) {
+		html := []byte(`<script nonce="__CSP_NONCE_VALUE__">test</script>`)
+		nonce := ""
+
+		result := replaceNoncePlaceholder(html, nonce)
+
+		assert.Equal(t, `<script nonce="">test</script>`, string(result))
+	})
+
+	t.Run("no_placeholder_returns_unchanged", func(t *testing.T) {
+		html := []byte(`<script>console.log('test');</script>`)
+		nonce := "abc123"
+
+		result := replaceNoncePlaceholder(html, nonce)
+
+		assert.Equal(t, string(html), string(result))
+	})
+
+	t.Run("handles_empty_html", func(t *testing.T) {
+		html := []byte(``)
+		nonce := "abc123"
+
+		result := replaceNoncePlaceholder(html, nonce)
+
+		assert.Empty(t, result)
+	})
+}
+
+func TestNonceHTMLPlaceholder(t *testing.T) {
+	t.Run("constant_value", func(t *testing.T) {
+		assert.Equal(t, "__CSP_NONCE_VALUE__", NonceHTMLPlaceholder)
+	})
+}
+
+// mockSettingsProvider implements PublicSettingsProvider for testing
+type mockSettingsProvider struct {
+	settings any
+	err      error
+	called   int
+}
+
+func (m *mockSettingsProvider) GetPublicSettingsForInjection(ctx context.Context) (any, error) {
+	m.called++
+	return m.settings, m.err
+}
+
+func TestFrontendServer_InjectSettings(t *testing.T) {
+	t.Run("injects_settings_with_nonce_placeholder", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"key": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		settingsJSON := []byte(`{"test":"data"}`)
+		result := server.injectSettings(settingsJSON)
+
+		// Should contain the script with nonce placeholder
+		assert.Contains(t, string(result), `<script nonce="__CSP_NONCE_VALUE__">`)
+		assert.Contains(t, string(result), `window.__APP_CONFIG__={"test":"data"};`)
+		assert.Contains(t, string(result), `</script></head>`)
+	})
+
+	t.Run("injects_before_head_close", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"key": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		settingsJSON := []byte(`{}`)
+		result := server.injectSettings(settingsJSON)
+
+		// Script should be injected before </head>
+		headCloseIndex := bytes.Index(result, []byte("</head>"))
+		scriptIndex := bytes.Index(result, []byte(`<script nonce="`))
+
+		assert.True(t, scriptIndex < headCloseIndex, "script should be before </head>")
+	})
+
+	t.Run("handles_complex_settings", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]any{
+				"nested": map[string]any{
+					"array": []int{1, 2, 3},
+				},
+			},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		settingsJSON := []byte(`{"nested":{"array":[1,2,3]},"special":"<>&"}`)
+		result := server.injectSettings(settingsJSON)
+
+		assert.Contains(t, string(result), `window.__APP_CONFIG__={"nested":{"array":[1,2,3]},"special":"<>&"};`)
+	})
+}
+
+func TestFrontendServer_ServeIndexHTML(t *testing.T) {
+	t.Run("serves_html_with_nonce", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		// Create a gin context with nonce
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+
+		// Set nonce in context (simulating SecurityHeaders middleware)
+		testNonce := "test-nonce-12345"
+		c.Set(middleware.CSPNonceKey, testNonce)
+
+		server.serveIndexHTML(c)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Contains(t, w.Header().Get("Content-Type"), "text/html")
+
+		body := w.Body.String()
+		// Nonce placeholder should be replaced
+		assert.NotContains(t, body, NonceHTMLPlaceholder)
+		assert.Contains(t, body, `nonce="`+testNonce+`"`)
+	})
+
+	t.Run("caches_html_content", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		// First request
+		w1 := httptest.NewRecorder()
+		c1, _ := gin.CreateTestContext(w1)
+		c1.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c1.Set(middleware.CSPNonceKey, "nonce1")
+
+		server.serveIndexHTML(c1)
+		assert.Equal(t, 1, provider.called)
+
+		// Second request - should use cache
+		w2 := httptest.NewRecorder()
+		c2, _ := gin.CreateTestContext(w2)
+		c2.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c2.Set(middleware.CSPNonceKey, "nonce2")
+
+		server.serveIndexHTML(c2)
+		// Settings provider should not be called again
+		assert.Equal(t, 1, provider.called)
+
+		// But nonce should be different
+		assert.Contains(t, w2.Body.String(), `nonce="nonce2"`)
+	})
+
+	t.Run("sets_etag_header", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c.Set(middleware.CSPNonceKey, "nonce123")
+
+		server.serveIndexHTML(c)
+
+		etag := w.Header().Get("ETag")
+		assert.NotEmpty(t, etag)
+		assert.True(t, strings.HasPrefix(etag, `"`))
+		assert.True(t, strings.HasSuffix(etag, `"`))
+	})
+
+	t.Run("returns_304_for_matching_etag", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		// Use a real router for proper 304 handling
+		router := gin.New()
+		router.Use(func(c *gin.Context) {
+			c.Set(middleware.CSPNonceKey, "test-nonce")
+			c.Next()
+		})
+		router.Use(server.Middleware())
+
+		// First request to populate cache and get ETag
+		w1 := httptest.NewRecorder()
+		req1 := httptest.NewRequest(http.MethodGet, "/", nil)
+		router.ServeHTTP(w1, req1)
+		etag := w1.Header().Get("ETag")
+		require.NotEmpty(t, etag)
+
+		// Second request with If-None-Match
+		w2 := httptest.NewRecorder()
+		req2 := httptest.NewRequest(http.MethodGet, "/", nil)
+		req2.Header.Set("If-None-Match", etag)
+		router.ServeHTTP(w2, req2)
+
+		assert.Equal(t, http.StatusNotModified, w2.Code)
+		assert.Empty(t, w2.Body.String())
+	})
+
+	t.Run("sets_cache_control_header", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c.Set(middleware.CSPNonceKey, "nonce123")
+
+		server.serveIndexHTML(c)
+
+		assert.Equal(t, "no-cache", w.Header().Get("Cache-Control"))
+	})
+
+	t.Run("fallback_on_settings_error", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			err: context.DeadlineExceeded,
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		// Invalidate cache to force settings fetch
+		server.InvalidateCache()
+
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c.Set(middleware.CSPNonceKey, "nonce123")
+
+		server.serveIndexHTML(c)
+
+		// Should still return 200 with base HTML
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Contains(t, w.Header().Get("Content-Type"), "text/html")
+	})
+}
+
+func TestFrontendServer_InvalidateCache(t *testing.T) {
+	t.Run("invalidates_cache", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		// First request to populate cache
+		w1 := httptest.NewRecorder()
+		c1, _ := gin.CreateTestContext(w1)
+		c1.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c1.Set(middleware.CSPNonceKey, "nonce1")
+
+		server.serveIndexHTML(c1)
+		assert.Equal(t, 1, provider.called)
+
+		// Invalidate cache
+		server.InvalidateCache()
+
+		// Update settings
+		provider.settings = map[string]string{"test": "new_value"}
+
+		// Second request should fetch new settings
+		w2 := httptest.NewRecorder()
+		c2, _ := gin.CreateTestContext(w2)
+		c2.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c2.Set(middleware.CSPNonceKey, "nonce2")
+
+		server.serveIndexHTML(c2)
+		assert.Equal(t, 2, provider.called)
+	})
+
+	t.Run("handles_nil_server", func(t *testing.T) {
+		var server *FrontendServer
+		// Should not panic
+		assert.NotPanics(t, func() {
+			server.InvalidateCache()
+		})
+	})
+
+	t.Run("handles_nil_cache", func(t *testing.T) {
+		server := &FrontendServer{}
+		// Should not panic
+		assert.NotPanics(t, func() {
+			server.InvalidateCache()
+		})
+	})
+}
+
+func TestFrontendServer_Middleware(t *testing.T) {
+	t.Run("skips_api_routes", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		apiPaths := []string{
+			"/api/v1/users",
+			"/v1/models",
+			"/v1beta/chat",
+			"/antigravity/test",
+			"/setup/init",
+			"/health",
+			"/responses",
+		}
+
+		for _, path := range apiPaths {
+			t.Run(path, func(t *testing.T) {
+				router := gin.New()
+				router.Use(server.Middleware())
+				nextCalled := false
+				router.GET(path, func(c *gin.Context) {
+					nextCalled = true
+					c.String(http.StatusOK, "ok")
+				})
+
+				w := httptest.NewRecorder()
+				req := httptest.NewRequest(http.MethodGet, path, nil)
+				router.ServeHTTP(w, req)
+
+				assert.True(t, nextCalled, "next handler should be called for API route")
+			})
+		}
+	})
+
+	t.Run("serves_index_for_spa_routes", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		router := gin.New()
+		router.Use(func(c *gin.Context) {
+			c.Set(middleware.CSPNonceKey, "test-nonce")
+			c.Next()
+		})
+		router.Use(server.Middleware())
+
+		spaPaths := []string{
+			"/",
+			"/dashboard",
+			"/users/123",
+			"/settings/profile",
+		}
+
+		for _, path := range spaPaths {
+			t.Run(path, func(t *testing.T) {
+				w := httptest.NewRecorder()
+				req := httptest.NewRequest(http.MethodGet, path, nil)
+				router.ServeHTTP(w, req)
+
+				assert.Equal(t, http.StatusOK, w.Code)
+				assert.Contains(t, w.Header().Get("Content-Type"), "text/html")
+			})
+		}
+	})
+
+	t.Run("serves_static_files", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		router := gin.New()
+		router.Use(server.Middleware())
+
+		// Request for existing static file
+		w := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/logo.png", nil)
+		router.ServeHTTP(w, req)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Contains(t, w.Header().Get("Content-Type"), "image/png")
+	})
+}
+
+func TestNewFrontendServer(t *testing.T) {
+	t.Run("creates_server_successfully", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+
+		require.NoError(t, err)
+		assert.NotNil(t, server)
+		assert.NotNil(t, server.distFS)
+		assert.NotNil(t, server.fileServer)
+		assert.NotNil(t, server.baseHTML)
+		assert.NotNil(t, server.cache)
+		assert.Equal(t, provider, server.settings)
+	})
+
+	t.Run("reads_base_html", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		assert.NotEmpty(t, server.baseHTML)
+		assert.Contains(t, string(server.baseHTML), "<!doctype html>")
+	})
+}
+
+func TestHasEmbeddedFrontend(t *testing.T) {
+	t.Run("returns_true_when_frontend_embedded", func(t *testing.T) {
+		result := HasEmbeddedFrontend()
+		assert.True(t, result)
+	})
+}
+
+// Tests for legacy ServeEmbeddedFrontend function
+func TestServeEmbeddedFrontend(t *testing.T) {
+	t.Run("serves_static_files", func(t *testing.T) {
+		middleware := ServeEmbeddedFrontend()
+
+		router := gin.New()
+		router.Use(middleware)
+
+		w := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/logo.png", nil)
+		router.ServeHTTP(w, req)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Contains(t, w.Header().Get("Content-Type"), "image/png")
+	})
+
+	t.Run("serves_index_html_for_root", func(t *testing.T) {
+		middleware := ServeEmbeddedFrontend()
+
+		router := gin.New()
+		router.Use(middleware)
+
+		w := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/", nil)
+		router.ServeHTTP(w, req)
+
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Contains(t, w.Header().Get("Content-Type"), "text/html")
+		assert.Contains(t, w.Body.String(), "<!doctype html>")
+	})
+
+	t.Run("serves_index_html_for_spa_routes", func(t *testing.T) {
+		middleware := ServeEmbeddedFrontend()
+
+		router := gin.New()
+		router.Use(middleware)
+
+		spaPaths := []string{"/dashboard", "/users/123", "/settings"}
+
+		for _, path := range spaPaths {
+			t.Run(path, func(t *testing.T) {
+				w := httptest.NewRecorder()
+				req := httptest.NewRequest(http.MethodGet, path, nil)
+				router.ServeHTTP(w, req)
+
+				assert.Equal(t, http.StatusOK, w.Code)
+				assert.Contains(t, w.Header().Get("Content-Type"), "text/html")
+			})
+		}
+	})
+
+	t.Run("skips_api_routes", func(t *testing.T) {
+		middleware := ServeEmbeddedFrontend()
+
+		apiPaths := []string{
+			"/api/users",
+			"/v1/models",
+			"/v1beta/chat",
+			"/antigravity/test",
+			"/setup/init",
+			"/health",
+			"/responses",
+		}
+
+		for _, path := range apiPaths {
+			t.Run(path, func(t *testing.T) {
+				nextCalled := false
+				router := gin.New()
+				router.Use(middleware)
+				router.GET(path, func(c *gin.Context) {
+					nextCalled = true
+					c.String(http.StatusOK, "ok")
+				})
+
+				w := httptest.NewRecorder()
+				req := httptest.NewRequest(http.MethodGet, path, nil)
+				router.ServeHTTP(w, req)
+
+				assert.True(t, nextCalled, "next handler should be called for API route")
+			})
+		}
+	})
+}
+
+// Tests for HTMLCache
+func TestHTMLCache(t *testing.T) {
+	t.Run("new_cache_returns_nil", func(t *testing.T) {
+		cache := NewHTMLCache()
+		assert.Nil(t, cache.Get())
+	})
+
+	t.Run("set_and_get", func(t *testing.T) {
+		cache := NewHTMLCache()
+		cache.SetBaseHTML([]byte("<html></html>"))
+
+		html := []byte("<html><body>test</body></html>")
+		settings := []byte(`{"key":"value"}`)
+		cache.Set(html, settings)
+
+		result := cache.Get()
+		require.NotNil(t, result)
+		assert.Equal(t, html, result.Content)
+		assert.NotEmpty(t, result.ETag)
+	})
+
+	t.Run("invalidate_clears_cache", func(t *testing.T) {
+		cache := NewHTMLCache()
+		cache.SetBaseHTML([]byte("<html></html>"))
+
+		html := []byte("<html><body>test</body></html>")
+		settings := []byte(`{"key":"value"}`)
+		cache.Set(html, settings)
+
+		require.NotNil(t, cache.Get())
+
+		cache.Invalidate()
+
+		assert.Nil(t, cache.Get())
+	})
+
+	t.Run("etag_changes_with_settings", func(t *testing.T) {
+		cache := NewHTMLCache()
+		cache.SetBaseHTML([]byte("<html></html>"))
+
+		html := []byte("<html><body>test</body></html>")
+
+		cache.Set(html, []byte(`{"v":1}`))
+		etag1 := cache.Get().ETag
+
+		cache.Invalidate()
+		cache.Set(html, []byte(`{"v":2}`))
+		etag2 := cache.Get().ETag
+
+		assert.NotEqual(t, etag1, etag2)
+	})
+
+	t.Run("etag_format", func(t *testing.T) {
+		cache := NewHTMLCache()
+		cache.SetBaseHTML([]byte("<html></html>"))
+
+		cache.Set([]byte("<html></html>"), []byte(`{}`))
+		result := cache.Get()
+
+		// ETag should be quoted
+		assert.True(t, strings.HasPrefix(result.ETag, `"`))
+		assert.True(t, strings.HasSuffix(result.ETag, `"`))
+		// Should contain dash separator
+		assert.Contains(t, result.ETag[1:len(result.ETag)-1], "-")
+	})
+}
+
+// Benchmark tests
+func BenchmarkReplaceNoncePlaceholder(b *testing.B) {
+	html := []byte(`<!DOCTYPE html><html><head><script nonce="__CSP_NONCE_VALUE__">window.__APP_CONFIG__={"test":"data"};</script></head><body></body></html>`)
+	nonce := "abcdefghijklmnop123456=="
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		replaceNoncePlaceholder(html, nonce)
+	}
+}
+
+func BenchmarkFrontendServerServeIndexHTML(b *testing.B) {
+	provider := &mockSettingsProvider{
+		settings: map[string]string{"test": "value"},
+	}
+
+	server, _ := NewFrontendServer(provider)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		w := httptest.NewRecorder()
+		c, _ := gin.CreateTestContext(w)
+		c.Request = httptest.NewRequest(http.MethodGet, "/", nil)
+		c.Set(middleware.CSPNonceKey, "test-nonce")
+
+		server.serveIndexHTML(c)
+	}
+}
diff --git a/deploy/config.example.yaml b/deploy/config.example.yaml
index ce2439f4..9e85d1ff 100644
--- a/deploy/config.example.yaml
+++ b/deploy/config.example.yaml
@@ -97,7 +97,9 @@ security:
     enabled: true
     # Default CSP policy (override if you host assets on other domains)
     # 默认 CSP 策略（如果静态资源托管在其他域名，请自行覆盖）
-    policy: "default-src 'self'; script-src 'self' https://challenges.cloudflare.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; img-src 'self' data: https:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https:; frame-src https://challenges.cloudflare.com; frame-ancestors 'none'; base-uri 'self'; form-action 'self'"
+    # Note: __CSP_NONCE__ will be replaced with 'nonce-xxx' at request time for inline script security
+    # 注意：__CSP_NONCE__ 会在请求时被替换为 'nonce-xxx'，用于内联脚本安全
+    policy: "default-src 'self'; script-src 'self' __CSP_NONCE__ https://challenges.cloudflare.com https://static.cloudflareinsights.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; img-src 'self' data: https:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https:; frame-src https://challenges.cloudflare.com; frame-ancestors 'none'; base-uri 'self'; form-action 'self'"
   proxy_probe:
     # Allow skipping TLS verification for proxy probe (debug only)
     # 允许代理探测时跳过 TLS 证书验证（仅用于调试）
diff --git a/frontend/src/router/index.ts b/frontend/src/router/index.ts
index 7e929400..9c507797 100644
--- a/frontend/src/router/index.ts
+++ b/frontend/src/router/index.ts
@@ -400,9 +400,33 @@ router.beforeEach((to, _from, next) => {
 
 /**
  * Navigation guard: Error handling
+ * Handles dynamic import failures caused by deployment updates
  */
 router.onError((error) => {
   console.error('Router error:', error)
+
+  // Check if this is a dynamic import failure (chunk loading error)
+  const isChunkLoadError =
+    error.message?.includes('Failed to fetch dynamically imported module') ||
+    error.message?.includes('Loading chunk') ||
+    error.message?.includes('Loading CSS chunk') ||
+    error.name === 'ChunkLoadError'
+
+  if (isChunkLoadError) {
+    // Avoid infinite reload loop by checking sessionStorage
+    const reloadKey = 'chunk_reload_attempted'
+    const lastReload = sessionStorage.getItem(reloadKey)
+    const now = Date.now()
+
+    // Allow reload if never attempted or more than 10 seconds ago
+    if (!lastReload || now - parseInt(lastReload) > 10000) {
+      sessionStorage.setItem(reloadKey, now.toString())
+      console.warn('Chunk load error detected, reloading page to fetch latest version...')
+      window.location.reload()
+    } else {
+      console.error('Chunk load error persists after reload. Please clear browser cache.')
+    }
+  }
 })
 
 export default router