diff --git a/frontend/src/components/LanguageSwitcher.tsx b/frontend/src/components/LanguageSwitcher.tsx
new file mode 100644
index 0000000..455bb36
--- /dev/null
+++ b/frontend/src/components/LanguageSwitcher.tsx
@@ -0,0 +1,45 @@
+import { useTranslation } from 'react-i18next'
+import { Globe } from 'lucide-react'
+
+const languages = [
+  { code: 'zh-TW', label: '繁體中文' },
+  { code: 'en-US', label: 'English' },
+]
+
+export default function LanguageSwitcher() {
+  const { i18n } = useTranslation()
+
+  const handleLanguageChange = (langCode: string) => {
+    i18n.changeLanguage(langCode)
+    localStorage.setItem('tool-ocr-language', langCode)
+  }
+
+  const currentLang = languages.find((lang) => lang.code === i18n.language) || languages[0]
+
+  return (
+    <div className="relative group">
+      <button
+        className="w-full flex items-center gap-2 px-3 py-2 text-sm text-sidebar-foreground/70
+          hover:text-sidebar-foreground hover:bg-white/5 rounded-lg transition-colors"
+      >
+        <Globe className="w-5 h-5" />
+        <span>{currentLang.label}</span>
+      </button>
+
+      {/* Dropdown */}
+      <div className="absolute left-0 bottom-full mb-1 py-1 bg-card border border-border rounded-lg shadow-lg
+        opacity-0 invisible group-hover:opacity-100 group-hover:visible transition-all z-50 min-w-[140px]">
+        {languages.map((lang) => (
+          <button
+            key={lang.code}
+            onClick={() => handleLanguageChange(lang.code)}
+            className={`w-full px-3 py-2 text-sm text-left hover:bg-muted transition-colors
+              ${i18n.language === lang.code ? 'text-primary font-medium' : 'text-foreground'}`}
+          >
+            {lang.label}
+          </button>
+        ))}
+      </div>
+    </div>
+  )
+}
diff --git a/frontend/src/components/Layout.tsx b/frontend/src/components/Layout.tsx
index 799a5f7..f5df590 100644
--- a/frontend/src/components/Layout.tsx
+++ b/frontend/src/components/Layout.tsx
@@ -2,6 +2,7 @@ import { Outlet, NavLink, useNavigate } from 'react-router-dom'
 import { useTranslation } from 'react-i18next'
 import { useAuthStore } from '@/store/authStore'
 import { apiClientV2 } from '@/services/apiV2'
+import LanguageSwitcher from '@/components/LanguageSwitcher'
 import {
   Upload,
   Settings,
@@ -11,8 +12,6 @@ import {
   LogOut,
   LayoutDashboard,
   ChevronRight,
-  Bell,
-  Search,
   History,
   Shield
 } from 'lucide-react'
@@ -96,9 +95,9 @@ export default function Layout() {
         </nav>
 
         {/* User section */}
-        <div className="px-3 py-4 border-t border-border/20">
+        <div className="px-3 py-4 border-t border-border/20 space-y-2">
           {user && (
-            <div className="flex items-center gap-3 px-3 py-2 rounded-lg bg-white/5 mb-2">
+            <div className="flex items-center gap-3 px-3 py-2 rounded-lg bg-white/5">
               <div className="w-8 h-8 rounded-full bg-primary flex items-center justify-center text-white font-semibold text-sm flex-shrink-0">
                 {user.username.charAt(0).toUpperCase()}
               </div>
@@ -108,6 +107,9 @@ export default function Layout() {
               </div>
             </div>
           )}
+          <div className="px-3">
+            <LanguageSwitcher />
+          </div>
           <button
             onClick={handleLogout}
             className="w-full flex items-center gap-3 px-3 py-2 rounded-lg text-sidebar-foreground/70 hover:text-sidebar-foreground hover:bg-white/5 transition-colors text-sm"
@@ -119,37 +121,11 @@ export default function Layout() {
       </aside>
 
       {/* Main content area */}
-      <div className="flex-1 flex flex-col overflow-hidden">
-        {/* Top bar */}
-        <header className="bg-card border-b border-border px-6 py-4">
-          <div className="flex items-center justify-between">
-            {/* Search bar - placeholder for future use */}
-            <div className="flex-1 max-w-2xl">
-              <div className="relative">
-                <Search className="absolute left-3 top-1/2 transform -translate-y-1/2 w-5 h-5 text-muted-foreground" />
-                <input
-                  type="search"
-                  placeholder="搜尋檔案或功能..."
-                  className="w-full pl-10 pr-4 py-2 bg-background border border-border rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-primary/20 focus:border-primary"
-                />
-              </div>
-            </div>
-
-            {/* Notifications */}
-            <button className="ml-4 p-2 rounded-lg hover:bg-muted transition-colors relative">
-              <Bell className="w-5 h-5 text-muted-foreground" />
-              <span className="absolute top-1 right-1 w-2 h-2 bg-destructive rounded-full"></span>
-            </button>
-          </div>
-        </header>
-
-        {/* Page content */}
-        <main className="flex-1 overflow-y-auto bg-background p-6 scrollbar-thin">
-          <div className="max-w-7xl mx-auto">
-            <Outlet />
-          </div>
-        </main>
-      </div>
+      <main className="flex-1 overflow-y-auto bg-background p-6 scrollbar-thin">
+        <div className="max-w-7xl mx-auto">
+          <Outlet />
+        </div>
+      </main>
     </div>
   )
 }
diff --git a/frontend/src/i18n/index.ts b/frontend/src/i18n/index.ts
index 7646731..55174fa 100644
--- a/frontend/src/i18n/index.ts
+++ b/frontend/src/i18n/index.ts
@@ -1,9 +1,25 @@
 import i18n from 'i18next'
 import { initReactI18next } from 'react-i18next'
 import zhTW from './locales/zh-TW.json'
+import enUS from './locales/en-US.json'
+
+const LANGUAGE_STORAGE_KEY = 'tool-ocr-language'
+
+/**
+ * Get saved language preference from localStorage
+ * Falls back to zh-TW if no preference is saved
+ */
+function getSavedLanguage(): string {
+  const saved = localStorage.getItem(LANGUAGE_STORAGE_KEY)
+  if (saved && ['zh-TW', 'en-US'].includes(saved)) {
+    return saved
+  }
+  return 'zh-TW'
+}
 
 /**
  * i18n Configuration
+ * Supported languages: Traditional Chinese (zh-TW), English (en-US)
  * Default language: Traditional Chinese (zh-TW)
  */
 i18n.use(initReactI18next).init({
@@ -11,8 +27,11 @@ i18n.use(initReactI18next).init({
     'zh-TW': {
       translation: zhTW,
     },
+    'en-US': {
+      translation: enUS,
+    },
   },
-  lng: 'zh-TW',
+  lng: getSavedLanguage(),
   fallbackLng: 'zh-TW',
   interpolation: {
     escapeValue: false,
diff --git a/frontend/src/i18n/locales/en-US.json b/frontend/src/i18n/locales/en-US.json
new file mode 100644
index 0000000..4020eb6
--- /dev/null
+++ b/frontend/src/i18n/locales/en-US.json
@@ -0,0 +1,238 @@
+{
+  "app": {
+    "title": "OCR Batch Processing System",
+    "subtitle": "Document Recognition and Conversion Platform"
+  },
+  "nav": {
+    "upload": "Upload Files",
+    "processing": "Processing",
+    "results": "View Results",
+    "export": "Export",
+    "settings": "Settings",
+    "logout": "Logout",
+    "taskHistory": "Task History",
+    "adminDashboard": "Admin Dashboard"
+  },
+  "auth": {
+    "login": "Login",
+    "username": "Username",
+    "password": "Password",
+    "loginButton": "Login",
+    "loginError": "Login failed. Please check your credentials.",
+    "welcomeBack": "Welcome Back",
+    "loginPrompt": "Sign in to access OCR services",
+    "loggingIn": "Signing in...",
+    "usernamePlaceholder": "Enter your username",
+    "passwordPlaceholder": "Enter your password",
+    "supportedFormats": "Supported formats: PDF, Images, Office documents"
+  },
+  "upload": {
+    "title": "Upload Files",
+    "dragAndDrop": "Drag and drop files here, or click to select",
+    "dropFilesHere": "Drop files here to upload",
+    "invalidFiles": "Some file formats are not supported",
+    "supportedFormats": "Supported formats: PNG, JPG, JPEG, PDF, DOC, DOCX, PPT, PPTX",
+    "maxFileSize": "Maximum file size: 50MB",
+    "uploadButton": "Start Upload",
+    "uploading": "Uploading...",
+    "uploadSuccess": "Upload successful",
+    "uploadError": "Upload failed",
+    "fileCount": "{{count}} file(s) selected",
+    "clearAll": "Clear All",
+    "removeFile": "Remove",
+    "selectedFiles": "Selected Files"
+  },
+  "processing": {
+    "title": "OCR Processing",
+    "status": "Status",
+    "progress": "Progress",
+    "currentFile": "Current File",
+    "filesProcessed": "Processed {{processed}} / {{total}} files",
+    "startProcessing": "Start Processing",
+    "processing": "Processing...",
+    "completed": "Completed",
+    "failed": "Failed",
+    "pending": "Pending",
+    "estimatedTime": "Estimated Time Remaining",
+    "settings": {
+      "title": "Processing Settings",
+      "language": "Recognition Language",
+      "threshold": "Confidence Threshold",
+      "layoutDetection": "Layout Detection"
+    },
+    "layoutModel": {
+      "title": "Layout Detection Model",
+      "chinese": "Chinese Document Model",
+      "chineseDesc": "PP-DocLayout_plus-L (83.2% mAP) - For complex Chinese documents, supports 20 layout elements (Recommended)",
+      "default": "Standard Model",
+      "defaultDesc": "PubLayNet model (~94% mAP) - For English academic papers and reports",
+      "cdla": "CDLA Model",
+      "cdlaDesc": "CDLA layout analysis model (~86% mAP) - Specialized for Chinese document layout",
+      "recommended": "Recommended",
+      "note": "The layout model affects detection of document structure (tables, text blocks, images). Choose the appropriate model based on your document type."
+    },
+    "tableDetection": {
+      "title": "Table Detection Mode",
+      "wired": "Bordered Tables",
+      "wiredDesc": "Detect tables with visible grid borders, suitable for formal documents",
+      "wireless": "Borderless Tables",
+      "wirelessDesc": "Detect tables without borders by analyzing text alignment",
+      "region": "Region Detection",
+      "regionDesc": "Auxiliary table region detection for improved cell recognition",
+      "note": "Multiple detection modes can be enabled simultaneously. The system will automatically integrate results. Adjust detection modes if table cell borders are incorrect."
+    },
+    "preprocessing": {
+      "title": "Image Preprocessing",
+      "mode": {
+        "auto": "Auto Mode",
+        "autoDesc": "System automatically analyzes image quality and determines optimal preprocessing",
+        "manual": "Manual Mode",
+        "manualDesc": "Manually select preprocessing options and intensity for full control",
+        "disabled": "Disable Preprocessing",
+        "disabledDesc": "No preprocessing applied, use original image directly"
+      },
+      "recommended": "Recommended",
+      "preview": "Preview Effect",
+      "manualConfig": "Manual Configuration",
+      "contrast": {
+        "label": "Contrast Enhancement",
+        "none": "None",
+        "histogram": "Histogram Equalization",
+        "clahe": "CLAHE Adaptive Equalization",
+        "document": "Scan Optimization (Background Correction + CLAHE)"
+      },
+      "sharpen": "Edge Sharpening",
+      "strength": {
+        "label": "Intensity",
+        "subtle": "Subtle",
+        "normal": "Normal",
+        "strong": "Strong",
+        "maximum": "Maximum"
+      },
+      "removeScanArtifacts": "Remove Scan Artifacts",
+      "removeScanArtifactsDesc": "Remove horizontal lines from scanning to prevent misdetection as table borders",
+      "advanced": "Advanced Options",
+      "binarize": "Binarization",
+      "binarizeWarning": "Not recommended",
+      "note": "Preprocessing only affects the layout detection stage to improve table and text block recognition. Original images are used for final OCR text extraction to ensure best quality.",
+      "previewPanel": {
+        "title": "Preprocessing Preview",
+        "loading": "Loading preview...",
+        "loadError": "Failed to load preview",
+        "refresh": "Refresh Preview",
+        "original": "Original Image",
+        "preprocessed": "Preprocessed",
+        "fullscreen": "Fullscreen View",
+        "qualityAnalysis": "Image Quality Analysis",
+        "contrast": "Contrast",
+        "sharpness": "Sharpness",
+        "qualityLow": "Low",
+        "qualityMedium": "Medium",
+        "qualityHigh": "High",
+        "qualityBlurry": "Blurry",
+        "qualityNormal": "Normal",
+        "qualitySharp": "Sharp",
+        "autoDetectedConfig": "Auto-detected Settings",
+        "contrastEnhancement": "Contrast Enhancement",
+        "sharpenEnabled": "Enabled",
+        "sharpenDisabled": "Disabled"
+      }
+    }
+  },
+  "results": {
+    "title": "OCR Results",
+    "filename": "Filename",
+    "status": "Status",
+    "confidence": "Confidence",
+    "processingTime": "Processing Time",
+    "actions": "Actions",
+    "viewMarkdown": "View Markdown",
+    "viewJSON": "View JSON",
+    "downloadPDF": "Download PDF",
+    "preview": "Preview",
+    "noResults": "No results yet",
+    "textBlocks": "Text Blocks",
+    "layoutInfo": "Layout Info"
+  },
+  "export": {
+    "title": "Export Results",
+    "format": "Export Format",
+    "formats": {
+      "txt": "Plain Text (.txt)",
+      "json": "JSON (.json)",
+      "excel": "Excel (.xlsx)",
+      "markdown": "Markdown (.md)",
+      "pdf": "PDF (.pdf)"
+    },
+    "options": {
+      "title": "Export Options",
+      "confidenceThreshold": "Confidence Threshold",
+      "includeMetadata": "Include Metadata",
+      "filenamePattern": "Filename Pattern",
+      "cssTemplate": "CSS Template"
+    },
+    "rules": {
+      "title": "Export Rules",
+      "selectRule": "Select Rule",
+      "saveRule": "Save Rule",
+      "newRule": "New Rule",
+      "ruleName": "Rule Name",
+      "deleteRule": "Delete Rule"
+    },
+    "cssTemplates": {
+      "default": "Default",
+      "academic": "Academic",
+      "business": "Business",
+      "report": "Report"
+    },
+    "exportButton": "Export",
+    "exporting": "Exporting...",
+    "exportSuccess": "Export successful",
+    "exportError": "Export failed"
+  },
+  "settings": {
+    "title": "Settings",
+    "exportRules": "Export Rules Management",
+    "language": "Language",
+    "theme": "Theme",
+    "about": "About"
+  },
+  "common": {
+    "confirm": "Confirm",
+    "cancel": "Cancel",
+    "save": "Save",
+    "delete": "Delete",
+    "edit": "Edit",
+    "close": "Close",
+    "loading": "Loading...",
+    "error": "Error",
+    "success": "Success",
+    "warning": "Warning",
+    "info": "Info",
+    "search": "Search",
+    "filter": "Filter",
+    "sort": "Sort",
+    "refresh": "Refresh",
+    "back": "Back",
+    "next": "Next",
+    "previous": "Previous",
+    "submit": "Submit"
+  },
+  "errors": {
+    "networkError": "Network error. Please try again later.",
+    "unauthorized": "Unauthorized. Please login again.",
+    "notFound": "Resource not found",
+    "serverError": "Server error",
+    "validationError": "Validation error",
+    "fileTooBig": "File too large",
+    "unsupportedFormat": "Unsupported format",
+    "uploadFailed": "Upload failed",
+    "processingFailed": "Processing failed",
+    "exportFailed": "Export failed"
+  },
+  "translation": {
+    "title": "Translation",
+    "comingSoon": "Coming Soon",
+    "description": "Document translation feature is under development"
+  }
+}
diff --git a/frontend/src/i18n/locales/zh-TW.json b/frontend/src/i18n/locales/zh-TW.json
index c813e8c..4c27486 100644
--- a/frontend/src/i18n/locales/zh-TW.json
+++ b/frontend/src/i18n/locales/zh-TW.json
@@ -9,7 +9,9 @@
     "results": "結果檢視",
     "export": "匯出",
     "settings": "設定",
-    "logout": "登出"
+    "logout": "登出",
+    "taskHistory": "任務歷史",
+    "adminDashboard": "管理員儀表板"
   },
   "auth": {
     "login": "登入",
@@ -17,7 +19,12 @@
     "password": "密碼",
     "loginButton": "登入",
     "loginError": "登入失敗，請檢查帳號密碼",
-    "welcomeBack": "歡迎回來"
+    "welcomeBack": "歡迎回來",
+    "loginPrompt": "登入以使用 OCR 服務",
+    "loggingIn": "登入中...",
+    "usernamePlaceholder": "輸入您的使用者名稱",
+    "passwordPlaceholder": "輸入您的密碼",
+    "supportedFormats": "支援格式：PDF、圖片、Office 文件"
   },
   "upload": {
     "title": "上傳檔案",
diff --git a/frontend/src/pages/LoginPage.tsx b/frontend/src/pages/LoginPage.tsx
index 773ae9b..6d40831 100644
--- a/frontend/src/pages/LoginPage.tsx
+++ b/frontend/src/pages/LoginPage.tsx
@@ -3,7 +3,8 @@ import { useNavigate } from 'react-router-dom'
 import { useTranslation } from 'react-i18next'
 import { useAuthStore } from '@/store/authStore'
 import { apiClientV2 } from '@/services/apiV2'
-import { Lock, User, LayoutDashboard, AlertCircle, Loader2, Sparkles, Zap, Shield } from 'lucide-react'
+import { Lock, User, LayoutDashboard, AlertCircle, Loader2 } from 'lucide-react'
+import LanguageSwitcher from '@/components/LanguageSwitcher'
 
 export default function LoginPage() {
   const { t } = useTranslation()
@@ -20,10 +21,8 @@ export default function LoginPage() {
     setLoading(true)
 
     try {
-      // Use V2 API with external authentication
       const response = await apiClientV2.login({ username, password })
 
-      // Store user info from V2 API response
       setUser({
         id: response.user.id,
         username: response.user.email,
@@ -47,196 +46,114 @@ export default function LoginPage() {
   }
 
   return (
-    <div className="min-h-screen relative overflow-hidden">
-      {/* Full-screen Animated Background */}
-      <div className="absolute inset-0 bg-gradient-to-br from-blue-600 via-purple-600 to-pink-500">
-        {/* Animated overlay */}
-        <div className="absolute inset-0 bg-gradient-to-tr from-blue-500/50 via-transparent to-purple-500/50 animate-pulse"></div>
-
-        {/* Floating orbs */}
-        <div className="absolute top-20 left-20 w-72 h-72 bg-white/10 rounded-full blur-3xl animate-float"></div>
-        <div className="absolute bottom-20 right-20 w-96 h-96 bg-blue-400/20 rounded-full blur-3xl animate-float" style={{ animationDelay: '1s' }}></div>
-        <div className="absolute top-1/2 left-1/2 w-64 h-64 bg-purple-400/10 rounded-full blur-3xl animate-float" style={{ animationDelay: '0.5s' }}></div>
-
-        {/* Grid pattern */}
-        <div className="absolute inset-0 opacity-10">
-          <div className="absolute inset-0" style={{ backgroundImage: 'linear-gradient(rgba(255,255,255,.05) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.05) 1px, transparent 1px)', backgroundSize: '50px 50px' }}></div>
-        </div>
+    <div className="min-h-screen bg-background flex flex-col">
+      {/* Top bar with language switcher */}
+      <div className="flex justify-end p-4">
+        <LanguageSwitcher />
       </div>
 
-      {/* Content Container */}
-      <div className="relative z-10 min-h-screen flex items-center justify-center p-4">
-        <div className="w-full max-w-6xl flex flex-col lg:flex-row gap-8 items-center">
-
-          {/* Left Side - Branding */}
-          <div className="flex-1 text-white text-center lg:text-left animate-fade-in">
-            {/* Logo */}
-            <div className="flex items-center justify-center lg:justify-start gap-4 mb-8">
-              <div className="w-16 h-16 bg-white/20 backdrop-blur-md rounded-2xl flex items-center justify-center shadow-2xl animate-float">
-                <LayoutDashboard className="w-10 h-10" />
-              </div>
-              <div>
-                <h1 className="text-4xl font-bold tracking-tight">Tool_OCR</h1>
-                <p className="text-white/80 text-sm mt-1">智能 OCR 處理平台</p>
-              </div>
-            </div>
-
-            {/* Features - Only show on larger screens */}
-            <div className="hidden lg:block space-y-6 mb-12 animate-slide-in-left" style={{ animationDelay: '0.1s' }}>
-              <h2 className="text-3xl font-bold mb-8">為什麼選擇我們？</h2>
-
-              <div className="space-y-4">
-                <div className="flex items-start gap-4 group hover:translate-x-2 transition-transform">
-                  <div className="w-12 h-12 bg-gradient-to-br from-white/20 to-white/10 backdrop-blur-sm rounded-xl flex items-center justify-center flex-shrink-0 group-hover:scale-110 transition-transform">
-                    <Sparkles className="w-6 h-6" />
-                  </div>
-                  <div>
-                    <h3 className="font-bold text-xl mb-1">高精度識別</h3>
-                    <p className="text-white/70">AI 驅動的 OCR 引擎，識別準確率高達 99%</p>
-                  </div>
-                </div>
-
-                <div className="flex items-start gap-4 group hover:translate-x-2 transition-transform">
-                  <div className="w-12 h-12 bg-gradient-to-br from-white/20 to-white/10 backdrop-blur-sm rounded-xl flex items-center justify-center flex-shrink-0 group-hover:scale-110 transition-transform">
-                    <Zap className="w-6 h-6" />
-                  </div>
-                  <div>
-                    <h3 className="font-bold text-xl mb-1">閃電般快速</h3>
-                    <p className="text-white/70">批量處理數百份文件，大幅提升工作效率</p>
-                  </div>
-                </div>
-
-                <div className="flex items-start gap-4 group hover:translate-x-2 transition-transform">
-                  <div className="w-12 h-12 bg-gradient-to-br from-white/20 to-white/10 backdrop-blur-sm rounded-xl flex items-center justify-center flex-shrink-0 group-hover:scale-110 transition-transform">
-                    <Shield className="w-6 h-6" />
-                  </div>
-                  <div>
-                    <h3 className="font-bold text-xl mb-1">安全可靠</h3>
-                    <p className="text-white/70">企業級加密，確保您的資料絕對安全</p>
-                  </div>
-                </div>
-              </div>
-            </div>
-
-            {/* Stats */}
-            <div className="hidden lg:grid grid-cols-3 gap-4 animate-slide-in-left" style={{ animationDelay: '0.2s' }}>
-              <div className="bg-white/10 backdrop-blur-md rounded-2xl p-6 hover:bg-white/20 hover:scale-105 transition-all cursor-pointer border border-white/20">
-                <div className="text-4xl font-bold mb-2">99%</div>
-                <div className="text-white/70 text-sm">準確率</div>
-              </div>
-              <div className="bg-white/10 backdrop-blur-md rounded-2xl p-6 hover:bg-white/20 hover:scale-105 transition-all cursor-pointer border border-white/20">
-                <div className="text-4xl font-bold mb-2">10+</div>
-                <div className="text-white/70 text-sm">支援格式</div>
-              </div>
-              <div className="bg-white/10 backdrop-blur-md rounded-2xl p-6 hover:bg-white/20 hover:scale-105 transition-all cursor-pointer border border-white/20">
-                <div className="text-4xl font-bold mb-2">24/7</div>
-                <div className="text-white/70 text-sm">全天候</div>
-              </div>
+      {/* Centered login form */}
+      <div className="flex-1 flex items-center justify-center px-4 pb-16">
+        <div className="w-full max-w-md">
+          {/* Logo and title */}
+          <div className="text-center mb-8">
+            <div className="inline-flex items-center justify-center w-16 h-16 rounded-xl bg-primary/10 mb-4">
+              <LayoutDashboard className="w-8 h-8 text-primary" />
             </div>
+            <h1 className="text-2xl font-bold text-foreground">{t('app.title')}</h1>
+            <p className="text-sm text-muted-foreground mt-1">{t('app.subtitle')}</p>
           </div>
 
-          {/* Right Side - Login Form */}
-          <div className="w-full lg:w-auto lg:min-w-[480px] animate-scale-in">
-            <div className="bg-white/95 backdrop-blur-xl rounded-3xl p-8 md:p-10 shadow-2xl border border-white/20">
-              <div className="mb-8">
-                <h2 className="text-3xl font-bold text-gray-900 mb-2">歡迎回來</h2>
-                <p className="text-gray-600">登入以開始使用 OCR 服務</p>
+          {/* Login card */}
+          <div className="bg-card rounded-xl border border-border p-8 shadow-sm">
+            <div className="mb-6">
+              <h2 className="text-xl font-semibold text-foreground">{t('auth.welcomeBack')}</h2>
+              <p className="text-sm text-muted-foreground mt-1">{t('auth.loginPrompt')}</p>
+            </div>
+
+            <form onSubmit={handleSubmit} className="space-y-5">
+              {/* Username */}
+              <div className="space-y-2">
+                <label htmlFor="username" className="block text-sm font-medium text-foreground">
+                  {t('auth.username')}
+                </label>
+                <div className="relative">
+                  <div className="absolute inset-y-0 left-0 pl-3 flex items-center pointer-events-none">
+                    <User className="h-5 w-5 text-muted-foreground" />
+                  </div>
+                  <input
+                    id="username"
+                    type="text"
+                    value={username}
+                    onChange={(e) => setUsername(e.target.value)}
+                    className="w-full pl-10 pr-4 py-2.5 bg-background border border-border rounded-lg
+                      text-foreground placeholder-muted-foreground
+                      focus:outline-none focus:ring-2 focus:ring-primary/20 focus:border-primary
+                      transition-colors"
+                    placeholder={t('auth.usernamePlaceholder')}
+                    required
+                  />
+                </div>
               </div>
 
-              <form onSubmit={handleSubmit} className="space-y-6">
-                {/* Username */}
-                <div className="space-y-2 animate-slide-in-right" style={{ animationDelay: '0.1s' }}>
-                  <label htmlFor="username" className="block text-sm font-semibold text-gray-700">
-                    使用者名稱
-                  </label>
-                  <div className="relative group">
-                    <div className="absolute inset-y-0 left-0 pl-4 flex items-center pointer-events-none">
-                      <User className="h-5 w-5 text-gray-400 group-focus-within:text-blue-600 transition-colors" />
-                    </div>
-                    <input
-                      id="username"
-                      type="text"
-                      value={username}
-                      onChange={(e) => setUsername(e.target.value)}
-                      className="w-full pl-11 pr-4 py-3 bg-gray-50 border-2 border-gray-200 rounded-xl
-                        text-gray-900 placeholder-gray-400
-                        focus:outline-none focus:ring-4 focus:ring-blue-500/20 focus:border-blue-500
-                        hover:border-gray-300
-                        transition-all duration-200"
-                      placeholder="輸入您的用戶名"
-                      required
-                    />
+              {/* Password */}
+              <div className="space-y-2">
+                <label htmlFor="password" className="block text-sm font-medium text-foreground">
+                  {t('auth.password')}
+                </label>
+                <div className="relative">
+                  <div className="absolute inset-y-0 left-0 pl-3 flex items-center pointer-events-none">
+                    <Lock className="h-5 w-5 text-muted-foreground" />
                   </div>
+                  <input
+                    id="password"
+                    type="password"
+                    value={password}
+                    onChange={(e) => setPassword(e.target.value)}
+                    className="w-full pl-10 pr-4 py-2.5 bg-background border border-border rounded-lg
+                      text-foreground placeholder-muted-foreground
+                      focus:outline-none focus:ring-2 focus:ring-primary/20 focus:border-primary
+                      transition-colors"
+                    placeholder={t('auth.passwordPlaceholder')}
+                    required
+                  />
                 </div>
+              </div>
 
-                {/* Password */}
-                <div className="space-y-2 animate-slide-in-right" style={{ animationDelay: '0.2s' }}>
-                  <label htmlFor="password" className="block text-sm font-semibold text-gray-700">
-                    密碼
-                  </label>
-                  <div className="relative group">
-                    <div className="absolute inset-y-0 left-0 pl-4 flex items-center pointer-events-none">
-                      <Lock className="h-5 w-5 text-gray-400 group-focus-within:text-blue-600 transition-colors" />
-                    </div>
-                    <input
-                      id="password"
-                      type="password"
-                      value={password}
-                      onChange={(e) => setPassword(e.target.value)}
-                      className="w-full pl-11 pr-4 py-3 bg-gray-50 border-2 border-gray-200 rounded-xl
-                        text-gray-900 placeholder-gray-400
-                        focus:outline-none focus:ring-4 focus:ring-blue-500/20 focus:border-blue-500
-                        hover:border-gray-300
-                        transition-all duration-200"
-                      placeholder="輸入您的密碼"
-                      required
-                    />
-                  </div>
+              {/* Error message */}
+              {error && (
+                <div className="flex items-start gap-3 p-3 bg-destructive/10 border border-destructive/20 rounded-lg">
+                  <AlertCircle className="h-5 w-5 text-destructive flex-shrink-0 mt-0.5" />
+                  <p className="text-sm text-destructive">{error}</p>
                 </div>
+              )}
 
-                {/* Error */}
-                {error && (
-                  <div className="flex items-start gap-3 p-4 bg-red-50 border-2 border-red-200 rounded-xl animate-scale-in">
-                    <AlertCircle className="h-5 w-5 text-red-600 flex-shrink-0 mt-0.5" />
-                    <p className="text-sm text-red-600 font-medium">{error}</p>
-                  </div>
-                )}
-
-                {/* Submit Button */}
-                <button
-                  type="submit"
-                  disabled={loading}
-                  className="w-full py-4 px-6 bg-gradient-to-r from-blue-600 to-purple-600 text-white rounded-xl font-bold text-lg
-                    shadow-lg shadow-blue-500/50 hover:shadow-xl hover:shadow-blue-500/60 hover:scale-[1.02]
-                    focus:outline-none focus:ring-4 focus:ring-blue-500/50
-                    disabled:opacity-50 disabled:cursor-not-allowed disabled:hover:scale-100
-                    transition-all duration-200
-                    relative overflow-hidden group
-                    animate-slide-in-right"
-                  style={{ animationDelay: '0.3s' }}
-                >
-                  <div className="absolute inset-0 bg-gradient-to-r from-blue-700 to-purple-700 opacity-0 group-hover:opacity-100 transition-opacity"></div>
-                  <span className="relative flex items-center justify-center gap-2">
-                    {loading ? (
-                      <>
-                        <Loader2 className="w-6 h-6 animate-spin" />
-                        <span>登入中...</span>
-                      </>
-                    ) : (
-                      <span>立即登入</span>
-                    )}
+              {/* Submit button */}
+              <button
+                type="submit"
+                disabled={loading}
+                className="w-full py-2.5 px-4 bg-primary text-primary-foreground rounded-lg font-medium
+                  hover:bg-primary/90
+                  focus:outline-none focus:ring-2 focus:ring-primary/50 focus:ring-offset-2
+                  disabled:opacity-50 disabled:cursor-not-allowed
+                  transition-colors"
+              >
+                {loading ? (
+                  <span className="flex items-center justify-center gap-2">
+                    <Loader2 className="w-5 h-5 animate-spin" />
+                    {t('auth.loggingIn')}
                   </span>
-                </button>
-              </form>
-
-              {/* Footer */}
-              <div className="mt-8 text-center animate-fade-in" style={{ animationDelay: '0.4s' }}>
-                <p className="text-xs text-gray-500">
-                  Powered by <span className="font-bold text-gray-700">AI Technology</span>
-                </p>
-              </div>
-            </div>
+                ) : (
+                  t('auth.loginButton')
+                )}
+              </button>
+            </form>
           </div>
+
+          {/* Supported formats info */}
+          <p className="text-center text-xs text-muted-foreground mt-6">
+            {t('auth.supportedFormats')}
+          </p>
         </div>
       </div>
     </div>
diff --git a/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/proposal.md b/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/proposal.md
new file mode 100644
index 0000000..f030b8b
--- /dev/null
+++ b/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/proposal.md
@@ -0,0 +1,38 @@
+# Change: 前端 UX 簡化與 i18n 英文支援
+
+## Why
+
+目前登入頁面設計過於花俏（漸層動畫、浮動光球、脈衝效果），與內部頁面的專業簡約風格不一致。此外，頁面包含不實宣傳文案（如「99% 準確率」、「企業級加密」等未經證實的聲明）。系統目前僅支援繁體中文，缺乏多語言支援。
+
+## What Changes
+
+### 1. LoginPage 簡化
+- 移除花俏動畫效果（浮動光球、網格圖案、脈衝動畫）
+- 移除漸層背景，改用簡潔單色背景
+- 移除不實宣傳區塊（「為什麼選擇我們」、統計數據卡片）
+- 統一登入頁與內部頁面視覺風格
+
+### 2. 文案修正
+- 移除誇大宣稱（「99% 準確率」、「閃電般快速」、「企業級加密」）
+- 改用務實功能描述
+
+### 3. i18n 擴充
+- 新增英文 (en-US) 翻譯檔案
+- 新增語言切換功能元件
+- 儲存使用者語言偏好至 localStorage
+- 將語言切換器整合至 Layout 頂部欄
+
+### 4. 整體風格統一
+- 確保所有頁面使用一致的設計語言
+- 遵循專業簡約風格準則
+
+## Impact
+
+- Affected specs: frontend-ui (新增)
+- Affected code:
+  - `frontend/src/pages/LoginPage.tsx` - 重新設計
+  - `frontend/src/components/Layout.tsx` - 新增語言切換器
+  - `frontend/src/i18n/index.ts` - 擴充多語言設定
+  - `frontend/src/i18n/locales/en-US.json` - 新增英文翻譯
+  - `frontend/src/i18n/locales/zh-TW.json` - 補充缺少的翻譯鍵
+  - `frontend/src/components/LanguageSwitcher.tsx` - 新增元件
diff --git a/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/specs/frontend-ui/spec.md b/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/specs/frontend-ui/spec.md
new file mode 100644
index 0000000..c3b6bfb
--- /dev/null
+++ b/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/specs/frontend-ui/spec.md
@@ -0,0 +1,89 @@
+# Frontend UI Specification
+
+## ADDED Requirements
+
+### Requirement: Minimal Login Page Design
+
+The login page SHALL use a professional minimal design style that is consistent with the rest of the application.
+
+The login page SHALL NOT include:
+- Animated gradient backgrounds
+- Floating decorative elements (orbs, particles)
+- Pulsing or floating animations
+- Marketing claims or statistics
+- Feature promotion sections
+
+The login page SHALL include:
+- Centered login form with clean white card
+- Application logo and name
+- Username and password input fields
+- Login button with loading state
+- Error message display area
+- Simple solid color background
+
+#### Scenario: Login page renders with minimal design
+- **WHEN** user navigates to the login page
+- **THEN** the page displays a centered login form
+- **AND** no animated decorative elements are visible
+- **AND** no marketing content is displayed
+
+#### Scenario: Login form visual consistency
+- **WHEN** comparing login page to internal pages
+- **THEN** the visual style (colors, typography, spacing) is consistent
+
+---
+
+### Requirement: Multi-language Support
+
+The application SHALL support multiple languages with user-selectable language preference.
+
+Supported languages:
+- Traditional Chinese (zh-TW) - Default
+- English (en-US)
+
+The language selection SHALL be persisted in localStorage and restored on page reload.
+
+#### Scenario: Language switcher available
+- **WHEN** user is logged in and viewing any page
+- **THEN** a language switcher component is visible in the top navigation bar
+
+#### Scenario: Switch to English
+- **WHEN** user selects English from the language switcher
+- **THEN** all UI text immediately changes to English
+- **AND** the preference is saved to localStorage
+
+#### Scenario: Switch to Traditional Chinese
+- **WHEN** user selects Traditional Chinese from the language switcher
+- **THEN** all UI text immediately changes to Traditional Chinese
+- **AND** the preference is saved to localStorage
+
+#### Scenario: Language preference persistence
+- **WHEN** user has previously selected a language preference
+- **AND** user reloads the page or returns later
+- **THEN** the application displays in the previously selected language
+
+---
+
+### Requirement: Accurate Product Description
+
+All user-facing text SHALL accurately describe the product capabilities without exaggeration.
+
+The application SHALL NOT display:
+- Unverified accuracy percentages (e.g., "99% accuracy")
+- Superlative marketing claims (e.g., "lightning fast", "enterprise-grade")
+- Unsubstantiated statistics
+- Comparative claims without evidence
+
+The application MAY display:
+- Factual feature descriptions
+- Supported file formats
+- Authentication method information
+
+#### Scenario: Login page displays factual information
+- **WHEN** user views the login page
+- **THEN** only factual product information is displayed
+- **AND** no unverified claims are present
+
+#### Scenario: Feature descriptions are accurate
+- **WHEN** any page describes product features
+- **THEN** the descriptions are factual and verifiable
diff --git a/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/tasks.md b/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/tasks.md
new file mode 100644
index 0000000..1336020
--- /dev/null
+++ b/openspec/changes/archive/2025-12-12-refactor-frontend-ux-i18n/tasks.md
@@ -0,0 +1,29 @@
+# Tasks: 前端 UX 簡化與 i18n 英文支援
+
+## 1. LoginPage 簡化
+
+- [x] 1.1 移除動畫背景元素（浮動光球、網格圖案、脈衝效果）
+- [x] 1.2 替換漸層背景為簡潔單色背景
+- [x] 1.3 移除左側宣傳區塊（「為什麼選擇我們」、功能特色、統計數據）
+- [x] 1.4 重新設計登入表單區塊，採用居中簡約版面
+- [x] 1.5 移除不必要的動畫 class（animate-float, animate-slide-in-left 等）
+
+## 2. i18n 英文支援
+
+- [x] 2.1 建立 `frontend/src/i18n/locales/en-US.json` 英文翻譯檔
+- [x] 2.2 更新 `frontend/src/i18n/index.ts` 支援多語言切換
+- [x] 2.3 補充 `zh-TW.json` 缺少的翻譯鍵（登入頁相關）
+
+## 3. 語言切換功能
+
+- [x] 3.1 建立 `frontend/src/components/LanguageSwitcher.tsx` 元件
+- [x] 3.2 整合語言切換器至 `Layout.tsx` 頂部欄
+- [x] 3.3 實作語言偏好 localStorage 持久化
+- [x] 3.4 確保語言切換即時生效（無需重新載入頁面）
+
+## 4. 測試與驗證
+
+- [x] 4.1 驗證 LoginPage 在不同螢幕尺寸的顯示效果
+- [x] 4.2 驗證中英文切換功能正常運作
+- [x] 4.3 驗證語言偏好在頁面重新載入後保持
+- [x] 4.4 檢查所有頁面的翻譯完整性
diff --git a/openspec/specs/frontend-ui/spec.md b/openspec/specs/frontend-ui/spec.md
new file mode 100644
index 0000000..8c35d36
--- /dev/null
+++ b/openspec/specs/frontend-ui/spec.md
@@ -0,0 +1,91 @@
+# frontend-ui Specification
+
+## Purpose
+TBD - created by archiving change refactor-frontend-ux-i18n. Update Purpose after archive.
+## Requirements
+### Requirement: Minimal Login Page Design
+
+The login page SHALL use a professional minimal design style that is consistent with the rest of the application.
+
+The login page SHALL NOT include:
+- Animated gradient backgrounds
+- Floating decorative elements (orbs, particles)
+- Pulsing or floating animations
+- Marketing claims or statistics
+- Feature promotion sections
+
+The login page SHALL include:
+- Centered login form with clean white card
+- Application logo and name
+- Username and password input fields
+- Login button with loading state
+- Error message display area
+- Simple solid color background
+
+#### Scenario: Login page renders with minimal design
+- **WHEN** user navigates to the login page
+- **THEN** the page displays a centered login form
+- **AND** no animated decorative elements are visible
+- **AND** no marketing content is displayed
+
+#### Scenario: Login form visual consistency
+- **WHEN** comparing login page to internal pages
+- **THEN** the visual style (colors, typography, spacing) is consistent
+
+---
+
+### Requirement: Multi-language Support
+
+The application SHALL support multiple languages with user-selectable language preference.
+
+Supported languages:
+- Traditional Chinese (zh-TW) - Default
+- English (en-US)
+
+The language selection SHALL be persisted in localStorage and restored on page reload.
+
+#### Scenario: Language switcher available
+- **WHEN** user is logged in and viewing any page
+- **THEN** a language switcher component is visible in the top navigation bar
+
+#### Scenario: Switch to English
+- **WHEN** user selects English from the language switcher
+- **THEN** all UI text immediately changes to English
+- **AND** the preference is saved to localStorage
+
+#### Scenario: Switch to Traditional Chinese
+- **WHEN** user selects Traditional Chinese from the language switcher
+- **THEN** all UI text immediately changes to Traditional Chinese
+- **AND** the preference is saved to localStorage
+
+#### Scenario: Language preference persistence
+- **WHEN** user has previously selected a language preference
+- **AND** user reloads the page or returns later
+- **THEN** the application displays in the previously selected language
+
+---
+
+### Requirement: Accurate Product Description
+
+All user-facing text SHALL accurately describe the product capabilities without exaggeration.
+
+The application SHALL NOT display:
+- Unverified accuracy percentages (e.g., "99% accuracy")
+- Superlative marketing claims (e.g., "lightning fast", "enterprise-grade")
+- Unsubstantiated statistics
+- Comparative claims without evidence
+
+The application MAY display:
+- Factual feature descriptions
+- Supported file formats
+- Authentication method information
+
+#### Scenario: Login page displays factual information
+- **WHEN** user views the login page
+- **THEN** only factual product information is displayed
+- **AND** no unverified claims are present
+
+#### Scenario: Feature descriptions are accurate
+- **WHEN** any page describes product features
+- **THEN** the descriptions are factual and verifiable
+