diff --git a/docs/theme.md b/docs/theme.md
index 1f7226883..294ed5d92 100644
--- a/docs/theme.md
+++ b/docs/theme.md
@@ -71,6 +71,8 @@
 
 应用使用 Vue I18n Composition API，语言标识为 `en`、`zh-Hans`、`zh-Hant`。资源按领域存放在 `frontend/src/i18n/locales/`，使用 `领域.功能.用途` 的语义 key，例如 `accounts.connectionTest.description`，三种语言保持相同 key 和具名参数
 
+默认语言为简体中文，浏览器本地保存的有效语言选择优先；未保存选择、保存值无效或存储不可用时使用简体中文
+
 业务语言包及对应 UI 文案按语言加载，首次只加载当前语言，加载成功后缓存资源。缺失消息显示为空，不回退到其他语言或显示 key；切换时语言包加载失败则保留当前语言
 
 - 标签、帮助、ARIA、通知和图表显式取消息；列定义、选项和展示投影使用响应式计算，不把翻译结果存进业务数据
diff --git a/frontend/src/i18n/locale.ts b/frontend/src/i18n/locale.ts
index d0442c9bf..84dda7078 100644
--- a/frontend/src/i18n/locale.ts
+++ b/frontend/src/i18n/locale.ts
@@ -12,25 +12,6 @@ export function isLocale(value: unknown): value is Locale {
   return localeOptions.some(option => option.value === value)
 }
 
-export function normalizeLocale(language: string): Locale {
-  try {
-    const { language: base, script, region } = new Intl.Locale(language)
-    if (base === 'zh') {
-      if (script === 'Hant')
-        return 'zh-Hant'
-      if (script === 'Hans')
-        return 'zh-Hans'
-      return region && ['TW', 'HK', 'MO'].includes(region)
-        ? 'zh-Hant'
-        : 'zh-Hans'
-    }
-  }
-  catch {
-    // 无效的浏览器语言使用应用默认语言
-  }
-  return 'en'
-}
-
 export function readInitialLocale(): Locale {
   try {
     const saved = localStorage.getItem(storageKey)
@@ -38,9 +19,9 @@ export function readInitialLocale(): Locale {
       return saved
   }
   catch {
-    // 存储不可用时继续使用浏览器语言
+    // 存储不可用时使用默认语言
   }
-  return normalizeLocale(navigator.language)
+  return 'zh-Hans'
 }
 
 export function applyLocale(value: string): void {
diff --git a/frontend/src/i18n/locales/en/auth.json b/frontend/src/i18n/locales/en/auth.json
index b6bb11a88..e21aae4c3 100644
--- a/frontend/src/i18n/locales/en/auth.json
+++ b/frontend/src/i18n/locales/en/auth.json
@@ -8,8 +8,8 @@
     "method": "Login method",
     "title": "Console login",
     "welcome": "Welcome back",
-    "username": "Admin account",
-    "usernamePlaceholder": "Enter your admin account",
+    "username": "Account",
+    "usernamePlaceholder": "Enter your account",
     "passwordPlaceholder": "Enter your password",
     "apiKeyPlaceholder": "Enter your API key",
     "pageLabel": "Log in to Codex Proxy RS",
diff --git a/frontend/src/i18n/locales/zh-Hans/auth.json b/frontend/src/i18n/locales/zh-Hans/auth.json
index b11001555..f3259ad9c 100644
--- a/frontend/src/i18n/locales/zh-Hans/auth.json
+++ b/frontend/src/i18n/locales/zh-Hans/auth.json
@@ -8,14 +8,14 @@
     "method": "选择登录方式",
     "title": "控制台登录",
     "welcome": "「 欢迎回来，登录以开始您的数据之旅 」",
-    "username": "管理员账号",
-    "usernamePlaceholder": "输入会话账号",
+    "username": "账号",
+    "usernamePlaceholder": "输入账号",
     "passwordPlaceholder": "输入会话密钥",
     "apiKeyPlaceholder": "输入 API密钥",
     "pageLabel": "Codex Proxy RS 登录",
     "password": "密码",
     "apiKey": "API密钥",
-    "adminRealm": "管理员",
+    "adminRealm": "Admin",
     "keyRealm": "API密钥"
   }
 }
diff --git a/frontend/src/i18n/locales/zh-Hant/auth.json b/frontend/src/i18n/locales/zh-Hant/auth.json
index f3eabd2fc..0f710a307 100644
--- a/frontend/src/i18n/locales/zh-Hant/auth.json
+++ b/frontend/src/i18n/locales/zh-Hant/auth.json
@@ -8,14 +8,14 @@
     "method": "選擇登錄方式",
     "title": "控制檯登錄",
     "welcome": "「 歡迎回來，登錄以開始您的數據之旅 」",
-    "username": "管理員賬號",
-    "usernamePlaceholder": "輸入會話賬號",
+    "username": "賬號",
+    "usernamePlaceholder": "輸入賬號",
     "passwordPlaceholder": "輸入會話密鑰",
     "apiKeyPlaceholder": "輸入 API密鑰",
     "pageLabel": "Codex Proxy RS 登錄",
     "password": "密碼",
     "apiKey": "API密鑰",
-    "adminRealm": "管理員",
+    "adminRealm": "Admin",
     "keyRealm": "API密鑰"
   }
 }