feat: add toast for no content

src/contexts/LanguageContext.tsx

@@ -1,6 +1,7 @@
 import React, { createContext, useContext, useState, useEffect } from 'react';
 import { translations, Language, TranslationKey } from '../lib/translations';
 import { detectLanguageByIP } from '../lib/ipLocation';
+import { updatePageMeta } from '../lib/seoHelper';
 
 interface LanguageContextType {
   language: Language;
@@ -25,6 +26,7 @@ export const LanguageProvider: React.FC<{ children: React.ReactNode }> = ({ chil
     
     // 如果用户已经手动选择过语言，则不进行IP检测
     if (saved === 'en' || saved === 'zh') {
+      updatePageMeta(saved); // Update meta tags on initial load
       return;
     }
 
@@ -32,18 +34,21 @@ export const LanguageProvider: React.FC<{ children: React.ReactNode }> = ({ chil
     detectLanguageByIP()
       .then((detectedLang) => {
         setLanguageState(detectedLang);
+        updatePageMeta(detectedLang); // Update meta tags after detection
         // 注意：这里不保存到 localStorage，让用户首次访问时使用IP检测的结果
         // 如果用户手动切换语言，才会保存到 localStorage
       })
       .catch((error) => {
         // IP检测失败时，保持使用浏览器语言检测的结果
         console.warn('Failed to detect language by IP:', error);
+        updatePageMeta(language); // Update with fallback language
       });
   }, []); // 仅在组件挂载时执行一次
 
   const setLanguage = (lang: Language) => {
     setLanguageState(lang);
     localStorage.setItem('language', lang);
+    updatePageMeta(lang); // Update page metadata when language changes
   };
 
   const t = translations[language];