diff --git a/docs/changelog/index.md b/docs/changelog/index.md
index 5cd7633d..ebbe7db6 100644
--- a/docs/changelog/index.md
+++ b/docs/changelog/index.md
@@ -26,6 +26,11 @@ sidebar: false
 
 - 支持 Service Worker 离线兜底：为启用 HTTPS 的网站下发 Service Worker 并缓存离线联系页，域名无法访问时浏览器展示联系站长页面，减少用户流失。可指定生效域名范围（仅对选中的 HTTPS 域名生效），配置位于「响应页面」-「联系页」，可在版本发布中批量生效。
 
+### 修复
+
+- 修复 `SWOfflineDomains` 校验与版本比对逻辑：校验器严格拒绝 JSON `null` 输入，配置版本 Diff 比对改用 JSON 序列化避免 `strings.Join` 逗号分隔符歧义。
+- 修复 HTML 编辑器预览标题：`HtmlEditorWorkspace` 支持传入 `previewTitle`，离线联系页预览使用「离线联系页实时预览」。
+
 ### 改进
 
 - 响应页面统一：将源站错误页与 Service Worker 离线兜底联系页整合至统一的「响应页面」（`/responses`）标签页中，移除原 `/error-pages` 独立路由。
diff --git a/frontend/app/(main)/responses/components/contact-page-tab.tsx b/frontend/app/(main)/responses/components/contact-page-tab.tsx
index 3f8c09ec..84e67fb8 100644
--- a/frontend/app/(main)/responses/components/contact-page-tab.tsx
+++ b/frontend/app/(main)/responses/components/contact-page-tab.tsx
@@ -194,6 +194,7 @@ export function ContactPageTab({
             preview={(html) => html}
             footerHint={null}
             showPreviewLink={false}
+            previewTitle='离线联系页实时预览'
           />
         </CardContent>
       </Card>
diff --git a/frontend/app/(main)/responses/components/error-page-tab.tsx b/frontend/app/(main)/responses/components/error-page-tab.tsx
index f376c50c..7a126837 100644
--- a/frontend/app/(main)/responses/components/error-page-tab.tsx
+++ b/frontend/app/(main)/responses/components/error-page-tab.tsx
@@ -42,9 +42,7 @@ export function ErrorPageTab({
   optionMap: Record<string, string>;
 }) {
   const queryClient = useQueryClient();
-  const [fields, setFields] = useState<ErrorPageFields>(
-    defaultErrorPageFields,
-  );
+  const [fields, setFields] = useState<ErrorPageFields>(defaultErrorPageFields);
   const [tagError, setTagError] = useState<string | null>(null);
 
   useEffect(() => {
diff --git a/frontend/components/common/html-editor-workspace.tsx b/frontend/components/common/html-editor-workspace.tsx
index a2369171..cfc061e4 100644
--- a/frontend/components/common/html-editor-workspace.tsx
+++ b/frontend/components/common/html-editor-workspace.tsx
@@ -21,6 +21,7 @@ type HtmlEditorWorkspaceProps = {
   preview?: (html: string) => string;
   footerHint?: React.ReactNode;
   showPreviewLink?: boolean;
+  previewTitle?: string;
 };
 
 /**
@@ -38,6 +39,7 @@ export function HtmlEditorWorkspace({
     </>
   ),
   showPreviewLink = true,
+  previewTitle = '源站错误页实时预览',
 }: HtmlEditorWorkspaceProps) {
   const containerRef = useRef<HTMLDivElement>(null);
   const [editorWidthPercent, setEditorWidthPercent] = useState(48);
@@ -145,7 +147,7 @@ export function HtmlEditorWorkspace({
           </div>
           <div className='flex-1 min-h-0 overflow-hidden bg-background'>
             <iframe
-              title='源站错误页实时预览'
+              title={previewTitle}
               sandbox=''
               srcDoc={previewSrcDoc}
               className='h-full w-full border-0 bg-background'
diff --git a/internal/apps/openflare/config_version/logics.go b/internal/apps/openflare/config_version/logics.go
index 67288ad2..973608dc 100644
--- a/internal/apps/openflare/config_version/logics.go
+++ b/internal/apps/openflare/config_version/logics.go
@@ -540,7 +540,7 @@ func diffOpenRestyOptionDetails(left openRestyConfigSnapshot, right openRestyCon
 	appendIfChanged("OriginErrorPageGetOnly", fmt.Sprintf("%t", left.OriginErrorPageGetOnly), fmt.Sprintf("%t", right.OriginErrorPageGetOnly))
 	appendIfChanged("SWOfflineEnabled", fmt.Sprintf("%t", left.SWOfflineEnabled), fmt.Sprintf("%t", right.SWOfflineEnabled))
 	appendIfChanged("SWOfflineHTML", left.SWOfflineHTML, right.SWOfflineHTML)
-	appendIfChanged("SWOfflineDomains", strings.Join(left.SWOfflineDomains, ","), strings.Join(right.SWOfflineDomains, ","))
+	appendIfChanged("SWOfflineDomains", encodeSWOfflineDomains(left.SWOfflineDomains), encodeSWOfflineDomains(right.SWOfflineDomains))
 	return changes
 }
 
@@ -555,6 +555,17 @@ func encodeOriginErrorPageStatusCodes(tags []string) string {
 	return string(payload)
 }
 
+func encodeSWOfflineDomains(domains []string) string {
+	if len(domains) == 0 {
+		return ""
+	}
+	payload, err := json.Marshal(domains)
+	if err != nil {
+		return strings.Join(domains, ",")
+	}
+	return string(payload)
+}
+
 func extractOptionDiffKeys(details []ConfigOptionDiffItem) []string {
 	keys := make([]string, 0, len(details))
 	for _, item := range details {
diff --git a/internal/apps/openflare/config_version/origin_error_page_snapshot_test.go b/internal/apps/openflare/config_version/origin_error_page_snapshot_test.go
index 8885e680..140c3f50 100644
--- a/internal/apps/openflare/config_version/origin_error_page_snapshot_test.go
+++ b/internal/apps/openflare/config_version/origin_error_page_snapshot_test.go
@@ -101,3 +101,21 @@ func TestDiffOpenRestyOptionDetailsOriginErrorPage(t *testing.T) {
 	assert.Equal(t, "", keys["OriginErrorPageHTML"].PreviousValue)
 	assert.Equal(t, "<p>x</p>", keys["OriginErrorPageHTML"].CurrentValue)
 }
+
+func TestDiffOpenRestyOptionDetailsSWOfflineDomains(t *testing.T) {
+	t.Parallel()
+
+	left := openRestyConfigSnapshot{
+		SWOfflineDomains: []string{"a.com,b.com"},
+	}
+	right := openRestyConfigSnapshot{
+		SWOfflineDomains: []string{"a.com", "b.com"},
+	}
+	details := diffOpenRestyOptionDetails(left, right)
+	keys := make(map[string]ConfigOptionDiffItem, len(details))
+	for _, item := range details {
+		keys[item.Key] = item
+	}
+	assert.Equal(t, `["a.com,b.com"]`, keys["SWOfflineDomains"].PreviousValue)
+	assert.Equal(t, `["a.com","b.com"]`, keys["SWOfflineDomains"].CurrentValue)
+}
diff --git a/internal/apps/openflare/option/openresty_validators.go b/internal/apps/openflare/option/openresty_validators.go
index 775358d6..dddcd475 100644
--- a/internal/apps/openflare/option/openresty_validators.go
+++ b/internal/apps/openflare/option/openresty_validators.go
@@ -260,7 +260,7 @@ func validateSWOfflineHTML(key, value string) error {
 
 func validateSWOfflineDomains(key, value string) error {
 	var domains []string
-	if err := json.Unmarshal([]byte(value), &domains); err != nil {
+	if err := json.Unmarshal([]byte(value), &domains); err != nil || domains == nil {
 		return fmt.Errorf("%s 必须为 JSON 字符串数组", key)
 	}
 	if len(domains) > maxSWOfflineDomains {
diff --git a/internal/apps/openflare/option/openresty_validators_test.go b/internal/apps/openflare/option/openresty_validators_test.go
index 6f4cebe8..c8d9767e 100644
--- a/internal/apps/openflare/option/openresty_validators_test.go
+++ b/internal/apps/openflare/option/openresty_validators_test.go
@@ -106,6 +106,7 @@ func TestValidateSWOfflineDomains(t *testing.T) {
 		{"single", `["example.com"]`, true},
 		{"multiple", `["example.com","api.example.com"]`, true},
 		{"invalid json", `not-json`, false},
+		{"null", "null", false},
 		{"empty element", `[""]`, false},
 		{"duplicate", `["example.com","example.com"]`, false},
 		{"whitespace dedup", `[" Example.com ","example.com"]`, false},