diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 95a41aa..4a71ed8 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -32,7 +32,7 @@ const AddPageNumbers = lazy(() => import('@/components/tools/AddPageNumbers'));
 function LoadingFallback() {
   return (
     <div className="flex min-h-[40vh] items-center justify-center">
-      <div className="h-10 w-10 animate-spin rounded-full border-4 border-primary-200 border-t-primary-600" />
+      <div className="h-10 w-10 animate-spin rounded-full border-4 border-primary-200 border-t-primary-600 dark:border-primary-800 dark:border-t-primary-400" />
     </div>
   );
 }
@@ -41,7 +41,7 @@ export default function App() {
   useDirection();
 
   return (
-    <div className="flex min-h-screen flex-col bg-slate-50">
+    <div className="flex min-h-screen flex-col bg-slate-50 transition-colors duration-300 dark:bg-slate-950">
       <Header />
 
       <main className="container mx-auto flex-1 px-4 py-8 sm:px-6 lg:px-8">
diff --git a/frontend/src/components/layout/Footer.tsx b/frontend/src/components/layout/Footer.tsx
index 5e5df3f..1b17cfb 100644
--- a/frontend/src/components/layout/Footer.tsx
+++ b/frontend/src/components/layout/Footer.tsx
@@ -6,11 +6,11 @@ export default function Footer() {
   const { t } = useTranslation();
 
   return (
-    <footer className="border-t border-slate-200 bg-slate-50">
+    <footer className="border-t border-slate-200 bg-slate-50 dark:border-slate-700 dark:bg-slate-900">
       <div className="mx-auto max-w-7xl px-4 py-8 sm:px-6 lg:px-8">
         <div className="flex flex-col items-center justify-between gap-4 sm:flex-row">
           {/* Brand */}
-          <div className="flex items-center gap-2 text-slate-600">
+          <div className="flex items-center gap-2 text-slate-600 dark:text-slate-400">
             <FileText className="h-5 w-5" />
             <span className="text-sm font-medium">
               © {new Date().getFullYear()} {t('common.appName')}
@@ -21,19 +21,19 @@ export default function Footer() {
           <div className="flex items-center gap-6">
             <Link
               to="/privacy"
-              className="text-sm text-slate-500 transition-colors hover:text-primary-600"
+              className="text-sm text-slate-500 transition-colors hover:text-primary-600 dark:text-slate-400 dark:hover:text-primary-400"
             >
               {t('common.privacy')}
             </Link>
             <Link
               to="/terms"
-              className="text-sm text-slate-500 transition-colors hover:text-primary-600"
+              className="text-sm text-slate-500 transition-colors hover:text-primary-600 dark:text-slate-400 dark:hover:text-primary-400"
             >
               {t('common.terms')}
             </Link>
             <Link
               to="/about"
-              className="text-sm text-slate-500 transition-colors hover:text-primary-600"
+              className="text-sm text-slate-500 transition-colors hover:text-primary-600 dark:text-slate-400 dark:hover:text-primary-400"
             >
               {t('common.about')}
             </Link>
diff --git a/frontend/src/components/layout/Header.tsx b/frontend/src/components/layout/Header.tsx
index 92bc57a..bf580f2 100644
--- a/frontend/src/components/layout/Header.tsx
+++ b/frontend/src/components/layout/Header.tsx
@@ -1,50 +1,174 @@
+import { useState, useEffect, useRef } from 'react';
 import { Link } from 'react-router-dom';
 import { useTranslation } from 'react-i18next';
-import { FileText, Globe } from 'lucide-react';
+import { FileText, Globe, Moon, Sun, Menu, X, ChevronDown } from 'lucide-react';
+
+interface LangOption {
+  code: string;
+  label: string;
+  flag: string;
+}
+
+const languages: LangOption[] = [
+  { code: 'en', label: 'English', flag: '🇺🇸' },
+  { code: 'ar', label: 'العربية', flag: '🇸🇦' },
+  { code: 'fr', label: 'Français', flag: '🇫🇷' },
+];
+
+function useDarkMode() {
+  const [isDark, setIsDark] = useState(() => {
+    if (typeof window === 'undefined') return false;
+    const stored = localStorage.getItem('theme');
+    if (stored) return stored === 'dark';
+    return window.matchMedia('(prefers-color-scheme: dark)').matches;
+  });
+
+  useEffect(() => {
+    const root = document.documentElement;
+    if (isDark) {
+      root.classList.add('dark');
+      localStorage.setItem('theme', 'dark');
+    } else {
+      root.classList.remove('dark');
+      localStorage.setItem('theme', 'light');
+    }
+  }, [isDark]);
+
+  return { isDark, toggle: () => setIsDark((v) => !v) };
+}
 
 export default function Header() {
   const { t, i18n } = useTranslation();
+  const { isDark, toggle: toggleDark } = useDarkMode();
+  const [langOpen, setLangOpen] = useState(false);
+  const [mobileOpen, setMobileOpen] = useState(false);
+  const langRef = useRef<HTMLDivElement>(null);
 
-  const toggleLanguage = () => {
-    const newLang = i18n.language === 'ar' ? 'en' : 'ar';
-    i18n.changeLanguage(newLang);
+  const currentLang = languages.find((l) => l.code === i18n.language) ?? languages[0];
+
+  // Close language dropdown on outside click
+  useEffect(() => {
+    function handleClick(e: MouseEvent) {
+      if (langRef.current && !langRef.current.contains(e.target as Node)) {
+        setLangOpen(false);
+      }
+    }
+    document.addEventListener('mousedown', handleClick);
+    return () => document.removeEventListener('mousedown', handleClick);
+  }, []);
+
+  const switchLang = (code: string) => {
+    i18n.changeLanguage(code);
+    setLangOpen(false);
   };
 
   return (
-    <header className="sticky top-0 z-50 border-b border-slate-200 bg-white/80 backdrop-blur-lg">
+    <header className="sticky top-0 z-50 border-b border-slate-200 bg-white/80 backdrop-blur-lg dark:border-slate-700 dark:bg-slate-900/80">
       <div className="mx-auto flex h-16 max-w-7xl items-center justify-between px-4 sm:px-6 lg:px-8">
         {/* Logo */}
-        <Link to="/" className="flex items-center gap-2 text-xl font-bold text-primary-600">
+        <Link to="/" className="flex items-center gap-2 text-xl font-bold text-primary-600 dark:text-primary-400">
           <FileText className="h-7 w-7" />
           <span>{t('common.appName')}</span>
         </Link>
 
-        {/* Navigation */}
+        {/* Desktop Navigation */}
         <nav className="hidden items-center gap-6 md:flex">
           <Link
             to="/"
-            className="text-sm font-medium text-slate-600 transition-colors hover:text-primary-600"
+            className="text-sm font-medium text-slate-600 transition-colors hover:text-primary-600 dark:text-slate-300 dark:hover:text-primary-400"
           >
             {t('common.home')}
           </Link>
           <Link
             to="/about"
-            className="text-sm font-medium text-slate-600 transition-colors hover:text-primary-600"
+            className="text-sm font-medium text-slate-600 transition-colors hover:text-primary-600 dark:text-slate-300 dark:hover:text-primary-400"
           >
             {t('common.about')}
           </Link>
         </nav>
 
-        {/* Language Toggle */}
-        <button
-          onClick={toggleLanguage}
-          className="flex items-center gap-1.5 rounded-lg px-3 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-100"
-          aria-label={t('common.language')}
-        >
-          <Globe className="h-4 w-4" />
-          <span>{i18n.language === 'ar' ? 'English' : 'العربية'}</span>
-        </button>
+        {/* Actions */}
+        <div className="flex items-center gap-2">
+          {/* Dark Mode Toggle */}
+          <button
+            onClick={toggleDark}
+            className="flex items-center justify-center rounded-xl p-2.5 text-slate-500 transition-colors hover:bg-slate-100 dark:text-slate-400 dark:hover:bg-slate-800"
+            aria-label={isDark ? t('common.lightMode') : t('common.darkMode')}
+            title={isDark ? t('common.lightMode') : t('common.darkMode')}
+          >
+            {isDark ? <Sun className="h-5 w-5" /> : <Moon className="h-5 w-5" />}
+          </button>
+
+          {/* Language Dropdown */}
+          <div className="relative" ref={langRef}>
+            <button
+              onClick={() => setLangOpen((v) => !v)}
+              className="flex items-center gap-1.5 rounded-xl px-3 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-100 dark:text-slate-300 dark:hover:bg-slate-800"
+              aria-label={t('common.language')}
+              aria-expanded={langOpen}
+              aria-haspopup="listbox"
+            >
+              <span className="text-lg leading-none">{currentLang.flag}</span>
+              <span className="hidden sm:inline">{currentLang.label}</span>
+              <ChevronDown className={`h-4 w-4 transition-transform duration-200 ${langOpen ? 'rotate-180' : ''}`} />
+            </button>
+
+            {/* Dropdown Menu */}
+            {langOpen && (
+              <div className="absolute end-0 top-full z-50 mt-2 w-44 origin-top-right animate-in fade-in slide-in-from-top-2 rounded-xl border border-slate-200 bg-white p-1 shadow-lg dark:border-slate-700 dark:bg-slate-800">
+                {languages.map((lang) => (
+                  <button
+                    key={lang.code}
+                    onClick={() => switchLang(lang.code)}
+                    className={`flex w-full items-center gap-3 rounded-lg px-3 py-2.5 text-sm font-medium transition-colors ${
+                      lang.code === i18n.language
+                        ? 'bg-primary-50 text-primary-700 dark:bg-primary-900/30 dark:text-primary-400'
+                        : 'text-slate-600 hover:bg-slate-50 dark:text-slate-300 dark:hover:bg-slate-700'
+                    }`}
+                    role="option"
+                    aria-selected={lang.code === i18n.language}
+                  >
+                    <span className="text-lg leading-none">{lang.flag}</span>
+                    <span>{lang.label}</span>
+                    {lang.code === i18n.language && (
+                      <span className="ms-auto text-primary-600 dark:text-primary-400">✓</span>
+                    )}
+                  </button>
+                ))}
+              </div>
+            )}
+          </div>
+
+          {/* Mobile Menu Toggle */}
+          <button
+            onClick={() => setMobileOpen((v) => !v)}
+            className="flex items-center justify-center rounded-xl p-2.5 text-slate-500 transition-colors hover:bg-slate-100 md:hidden dark:text-slate-400 dark:hover:bg-slate-800"
+            aria-label="Menu"
+          >
+            {mobileOpen ? <X className="h-5 w-5" /> : <Menu className="h-5 w-5" />}
+          </button>
+        </div>
       </div>
+
+      {/* Mobile Navigation */}
+      {mobileOpen && (
+        <nav className="border-t border-slate-200 bg-white px-4 pb-4 pt-2 md:hidden dark:border-slate-700 dark:bg-slate-900">
+          <Link
+            to="/"
+            onClick={() => setMobileOpen(false)}
+            className="block rounded-lg px-3 py-2.5 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-50 dark:text-slate-300 dark:hover:bg-slate-800"
+          >
+            {t('common.home')}
+          </Link>
+          <Link
+            to="/about"
+            onClick={() => setMobileOpen(false)}
+            className="block rounded-lg px-3 py-2.5 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-50 dark:text-slate-300 dark:hover:bg-slate-800"
+          >
+            {t('common.about')}
+          </Link>
+        </nav>
+      )}
     </header>
   );
 }
diff --git a/frontend/src/components/shared/DownloadButton.tsx b/frontend/src/components/shared/DownloadButton.tsx
index edd8533..a717fb0 100644
--- a/frontend/src/components/shared/DownloadButton.tsx
+++ b/frontend/src/components/shared/DownloadButton.tsx
@@ -16,13 +16,13 @@ export default function DownloadButton({ result, onStartOver }: DownloadButtonPr
   if (!result.download_url) return null;
 
   return (
-    <div className="rounded-2xl bg-emerald-50 p-6 ring-1 ring-emerald-200">
+    <div className="rounded-2xl bg-emerald-50 p-6 ring-1 ring-emerald-200 dark:bg-emerald-900/20 dark:ring-emerald-800">
       {/* Success header */}
       <div className="mb-4 text-center">
-        <p className="text-lg font-semibold text-emerald-800">
+        <p className="text-lg font-semibold text-emerald-800 dark:text-emerald-300">
           {t('result.conversionComplete')}
         </p>
-        <p className="mt-1 text-sm text-emerald-600">
+        <p className="mt-1 text-sm text-emerald-600 dark:text-emerald-400">
           {t('result.downloadReady')}
         </p>
       </div>
@@ -31,24 +31,24 @@ export default function DownloadButton({ result, onStartOver }: DownloadButtonPr
       {(result.original_size || result.compressed_size) && (
         <div className="mb-4 grid grid-cols-2 gap-3 sm:grid-cols-3">
           {result.original_size && (
-            <div className="rounded-lg bg-white p-3 text-center">
-              <p className="text-xs text-slate-500">{t('result.originalSize')}</p>
-              <p className="text-sm font-semibold text-slate-900">
+            <div className="rounded-lg bg-white p-3 text-center dark:bg-slate-800">
+              <p className="text-xs text-slate-500 dark:text-slate-400">{t('result.originalSize')}</p>
+              <p className="text-sm font-semibold text-slate-900 dark:text-slate-100">
                 {formatFileSize(result.original_size)}
               </p>
             </div>
           )}
           {result.compressed_size && (
-            <div className="rounded-lg bg-white p-3 text-center">
-              <p className="text-xs text-slate-500">{t('result.newSize')}</p>
-              <p className="text-sm font-semibold text-slate-900">
+            <div className="rounded-lg bg-white p-3 text-center dark:bg-slate-800">
+              <p className="text-xs text-slate-500 dark:text-slate-400">{t('result.newSize')}</p>
+              <p className="text-sm font-semibold text-slate-900 dark:text-slate-100">
                 {formatFileSize(result.compressed_size)}
               </p>
             </div>
           )}
           {result.reduction_percent !== undefined && (
-            <div className="rounded-lg bg-white p-3 text-center">
-              <p className="text-xs text-slate-500">{t('result.reduction')}</p>
+            <div className="rounded-lg bg-white p-3 text-center dark:bg-slate-800">
+              <p className="text-xs text-slate-500 dark:text-slate-400">{t('result.reduction')}</p>
               <p className="text-sm font-semibold text-emerald-600">
                 {result.reduction_percent}%
               </p>
@@ -70,7 +70,7 @@ export default function DownloadButton({ result, onStartOver }: DownloadButtonPr
       </a>
 
       {/* Expiry notice */}
-      <div className="mt-3 flex items-center justify-center gap-1.5 text-xs text-slate-500">
+      <div className="mt-3 flex items-center justify-center gap-1.5 text-xs text-slate-500 dark:text-slate-400">
         <Clock className="h-3.5 w-3.5" />
         {t('result.linkExpiry')}
       </div>
@@ -78,7 +78,7 @@ export default function DownloadButton({ result, onStartOver }: DownloadButtonPr
       {/* Start over */}
       <button
         onClick={onStartOver}
-        className="mt-4 flex w-full items-center justify-center gap-2 text-sm font-medium text-primary-600 transition-colors hover:text-primary-700"
+        className="mt-4 flex w-full items-center justify-center gap-2 text-sm font-medium text-primary-600 transition-colors hover:text-primary-700 dark:text-primary-400 dark:hover:text-primary-300"
       >
         <RotateCcw className="h-4 w-4" />
         {t('common.startOver')}
diff --git a/frontend/src/components/shared/FileUploader.tsx b/frontend/src/components/shared/FileUploader.tsx
index f775897..228489c 100644
--- a/frontend/src/components/shared/FileUploader.tsx
+++ b/frontend/src/components/shared/FileUploader.tsx
@@ -69,13 +69,13 @@ export default function FileUploader({
               isDragActive ? 'text-primary-500' : 'text-slate-400'
             }`}
           />
-          <p className="mb-2 text-base font-medium text-slate-700">
+          <p className="mb-2 text-base font-medium text-slate-700 dark:text-slate-300">
             {t('common.dragDrop')}
           </p>
           {acceptLabel && (
-            <p className="text-sm text-slate-500">{acceptLabel}</p>
+            <p className="text-sm text-slate-500 dark:text-slate-400">{acceptLabel}</p>
           )}
-          <p className="mt-1 text-xs text-slate-400">
+          <p className="mt-1 text-xs text-slate-400 dark:text-slate-500">
             {t('common.maxSize', { size: maxSizeMB })}
           </p>
         </div>
@@ -83,13 +83,13 @@ export default function FileUploader({
 
       {/* Selected File */}
       {file && !isUploading && (
-        <div className="flex items-center gap-3 rounded-xl bg-primary-50 p-4 ring-1 ring-primary-200">
-          <File className="h-8 w-8 flex-shrink-0 text-primary-600" />
+        <div className="flex items-center gap-3 rounded-xl bg-primary-50 p-4 ring-1 ring-primary-200 dark:bg-primary-900/20 dark:ring-primary-800">
+          <File className="h-8 w-8 flex-shrink-0 text-primary-600 dark:text-primary-400" />
           <div className="min-w-0 flex-1">
-            <p className="truncate text-sm font-medium text-slate-900">
+            <p className="truncate text-sm font-medium text-slate-900 dark:text-slate-100">
               {file.name}
             </p>
-            <p className="text-xs text-slate-500">{formatFileSize(file.size)}</p>
+            <p className="text-xs text-slate-500 dark:text-slate-400">{formatFileSize(file.size)}</p>
           </div>
           {onReset && (
             <button
@@ -105,12 +105,12 @@ export default function FileUploader({
 
       {/* Upload Progress */}
       {isUploading && (
-        <div className="rounded-xl bg-slate-50 p-4 ring-1 ring-slate-200">
+        <div className="rounded-xl bg-slate-50 p-4 ring-1 ring-slate-200 dark:bg-slate-800 dark:ring-slate-700">
           <div className="mb-2 flex items-center justify-between">
-            <span className="text-sm font-medium text-slate-700">
+            <span className="text-sm font-medium text-slate-700 dark:text-slate-300">
               {t('common.upload')}...
             </span>
-            <span className="text-sm text-slate-500">{uploadProgress}%</span>
+            <span className="text-sm text-slate-500 dark:text-slate-400">{uploadProgress}%</span>
           </div>
           <div className="h-2 w-full overflow-hidden rounded-full bg-slate-200">
             <div
@@ -123,8 +123,8 @@ export default function FileUploader({
 
       {/* Error */}
       {error && (
-        <div className="mt-3 rounded-xl bg-red-50 p-3 ring-1 ring-red-200">
-          <p className="text-sm text-red-700">{error}</p>
+        <div className="mt-3 rounded-xl bg-red-50 p-3 ring-1 ring-red-200 dark:bg-red-900/20 dark:ring-red-800">
+          <p className="text-sm text-red-700 dark:text-red-400">{error}</p>
         </div>
       )}
     </div>
diff --git a/frontend/src/components/shared/ProgressBar.tsx b/frontend/src/components/shared/ProgressBar.tsx
index 6cf1002..9f44ef3 100644
--- a/frontend/src/components/shared/ProgressBar.tsx
+++ b/frontend/src/components/shared/ProgressBar.tsx
@@ -15,17 +15,17 @@ export default function ProgressBar({ state, message }: ProgressBarProps) {
   const isComplete = state === 'SUCCESS';
 
   return (
-    <div className="rounded-xl bg-slate-50 p-5 ring-1 ring-slate-200">
+    <div className="rounded-xl bg-slate-50 p-5 ring-1 ring-slate-200 dark:bg-slate-800 dark:ring-slate-700">
       <div className="flex items-center gap-3">
         {isActive && (
-          <Loader2 className="h-6 w-6 animate-spin text-primary-600" />
+          <Loader2 className="h-6 w-6 animate-spin text-primary-600 dark:text-primary-400" />
         )}
         {isComplete && (
           <CheckCircle2 className="h-6 w-6 text-emerald-600" />
         )}
 
         <div className="flex-1">
-          <p className="text-sm font-medium text-slate-700">
+          <p className="text-sm font-medium text-slate-700 dark:text-slate-300">
             {message || t('common.processing')}
           </p>
         </div>
@@ -33,7 +33,7 @@ export default function ProgressBar({ state, message }: ProgressBarProps) {
 
       {/* Animated progress bar for active states */}
       {isActive && (
-        <div className="mt-3 h-1.5 w-full overflow-hidden rounded-full bg-slate-200">
+        <div className="mt-3 h-1.5 w-full overflow-hidden rounded-full bg-slate-200 dark:bg-slate-700">
           <div className="progress-bar-animated h-full w-2/3 rounded-full bg-primary-500 transition-all" />
         </div>
       )}
diff --git a/frontend/src/components/shared/ToolCard.tsx b/frontend/src/components/shared/ToolCard.tsx
index b541434..601f2e4 100644
--- a/frontend/src/components/shared/ToolCard.tsx
+++ b/frontend/src/components/shared/ToolCard.tsx
@@ -30,10 +30,10 @@ export default function ToolCard({
           {icon}
         </div>
         <div className="min-w-0 flex-1">
-          <h3 className="text-base font-semibold text-slate-900 group-hover:text-primary-600 transition-colors">
+          <h3 className="text-base font-semibold text-slate-900 group-hover:text-primary-600 transition-colors dark:text-slate-100 dark:group-hover:text-primary-400">
             {title}
           </h3>
-          <p className="mt-1 text-sm text-slate-500 line-clamp-2">
+          <p className="mt-1 text-sm text-slate-500 line-clamp-2 dark:text-slate-400">
             {description}
           </p>
         </div>
diff --git a/frontend/src/i18n/ar.json b/frontend/src/i18n/ar.json
index e195b6f..38f4131 100644
--- a/frontend/src/i18n/ar.json
+++ b/frontend/src/i18n/ar.json
@@ -17,7 +17,9 @@
     "privacy": "سياسة الخصوصية",
     "terms": "شروط الاستخدام",
     "language": "اللغة",
-    "allTools": "كل الأدوات"
+    "allTools": "كل الأدوات",
+    "darkMode": "الوضع الداكن",
+    "lightMode": "الوضع الفاتح"
   },
   "home": {
     "hero": "حوّل ملفاتك فوراً",
diff --git a/frontend/src/i18n/en.json b/frontend/src/i18n/en.json
index bc99cbf..84a1e3f 100644
--- a/frontend/src/i18n/en.json
+++ b/frontend/src/i18n/en.json
@@ -17,7 +17,9 @@
     "privacy": "Privacy Policy",
     "terms": "Terms of Service",
     "language": "Language",
-    "allTools": "All Tools"
+    "allTools": "All Tools",
+    "darkMode": "Dark Mode",
+    "lightMode": "Light Mode"
   },
   "home": {
     "hero": "Transform Your Files Instantly",
diff --git a/frontend/src/i18n/fr.json b/frontend/src/i18n/fr.json
new file mode 100644
index 0000000..8ee2fd3
--- /dev/null
+++ b/frontend/src/i18n/fr.json
@@ -0,0 +1,184 @@
+{
+  "common": {
+    "appName": "SaaS-PDF",
+    "tagline": "Outils de fichiers en ligne gratuits",
+    "upload": "Télécharger un fichier",
+    "download": "Télécharger",
+    "processing": "Traitement en cours...",
+    "dragDrop": "Glissez-déposez votre fichier ici, ou cliquez pour parcourir",
+    "maxSize": "Taille maximale du fichier : {{size}} Mo",
+    "tryOtherTools": "Essayer d'autres outils",
+    "error": "Erreur",
+    "success": "Succès",
+    "loading": "Chargement...",
+    "startOver": "Recommencer",
+    "home": "Accueil",
+    "about": "À propos",
+    "privacy": "Politique de confidentialité",
+    "terms": "Conditions d'utilisation",
+    "language": "Langue",
+    "allTools": "Tous les outils",
+    "darkMode": "Mode sombre",
+    "lightMode": "Mode clair"
+  },
+  "home": {
+    "hero": "Transformez vos fichiers instantanément",
+    "heroSub": "Outils en ligne gratuits pour le traitement de PDF, images, vidéos et textes. Aucune inscription requise.",
+    "popularTools": "Outils populaires",
+    "pdfTools": "Outils PDF",
+    "imageTools": "Outils d'images",
+    "videoTools": "Outils vidéo",
+    "textTools": "Outils de texte"
+  },
+  "tools": {
+    "pdfToWord": {
+      "title": "PDF vers Word",
+      "description": "Convertissez gratuitement des fichiers PDF en documents Word modifiables.",
+      "shortDesc": "PDF → Word"
+    },
+    "wordToPdf": {
+      "title": "Word vers PDF",
+      "description": "Convertissez gratuitement des documents Word (DOC, DOCX) au format PDF.",
+      "shortDesc": "Word → PDF"
+    },
+    "compressPdf": {
+      "title": "Compresser PDF",
+      "description": "Réduisez la taille du fichier PDF tout en maintenant la qualité. Choisissez votre niveau de compression.",
+      "shortDesc": "Compresser PDF",
+      "qualityLow": "Compression maximale",
+      "qualityMedium": "Équilibré",
+      "qualityHigh": "Haute qualité"
+    },
+    "imageConvert": {
+      "title": "Convertisseur d'images",
+      "description": "Convertissez instantanément des images entre les formats JPG, PNG et WebP.",
+      "shortDesc": "Convertir des images"
+    },
+    "videoToGif": {
+      "title": "Vidéo en GIF",
+      "description": "Créez des GIFs animés à partir de clips vidéo. Personnalisez le temps de début, la durée et la qualité.",
+      "shortDesc": "Vidéo → GIF",
+      "startTime": "Temps de début (secondes)",
+      "duration": "Durée (secondes)",
+      "fps": "Images par seconde",
+      "width": "Largeur (pixels)"
+    },
+    "wordCounter": {
+      "title": "Compteur de mots",
+      "description": "Comptez instantanément les mots, caractères, phrases et paragraphes de votre texte.",
+      "shortDesc": "Compter les mots",
+      "words": "Mots",
+      "characters": "Caractères",
+      "sentences": "Phrases",
+      "paragraphs": "Paragraphes",
+      "placeholder": "Tapez ou collez votre texte ici..."
+    },
+    "textCleaner": {
+      "title": "Nettoyeur de texte",
+      "description": "Supprimez les espaces en trop, convertissez la casse et nettoyez votre texte instantanément.",
+      "shortDesc": "Nettoyer le texte",
+      "removeSpaces": "Supprimer les espaces en trop",
+      "toUpperCase": "MAJUSCULES",
+      "toLowerCase": "minuscules",
+      "toTitleCase": "Casse Du Titre",
+      "toSentenceCase": "Casse de phrase",
+      "removeDiacritics": "Supprimer les signes diacritiques arabes",
+      "copyResult": "Copier le résultat"
+    },
+    "mergePdf": {
+      "title": "Fusionner PDF",
+      "description": "Combinez plusieurs fichiers PDF en un seul document. Gratuit et rapide.",
+      "shortDesc": "Fusionner PDF",
+      "selectFiles": "Sélectionner des fichiers PDF",
+      "addMore": "Ajouter plus de fichiers",
+      "filesSelected": "{{count}} fichiers sélectionnés",
+      "dragToReorder": "Glissez les fichiers pour les réorganiser"
+    },
+    "splitPdf": {
+      "title": "Diviser PDF",
+      "description": "Divisez un PDF en pages individuelles ou extrayez des plages de pages spécifiques.",
+      "shortDesc": "Diviser PDF",
+      "allPages": "Toutes les pages",
+      "pageRange": "Plage de pages",
+      "rangeHint": "ex. 1,3,5-8",
+      "rangePlaceholder": "Entrez les pages : 1,3,5-8"
+    },
+    "rotatePdf": {
+      "title": "Pivoter PDF",
+      "description": "Pivotez toutes les pages d'un PDF de 90°, 180° ou 270° degrés.",
+      "shortDesc": "Pivoter PDF",
+      "angle": "Angle de rotation",
+      "90": "90° Sens horaire",
+      "180": "180° Retourner",
+      "270": "270° Sens anti-horaire"
+    },
+    "pdfToImages": {
+      "title": "PDF en images",
+      "description": "Convertissez chaque page d'un PDF en images haute qualité (PNG ou JPG).",
+      "shortDesc": "PDF → Images",
+      "format": "Format d'image",
+      "dpi": "Résolution (DPI)",
+      "dpiLow": "72 — Écran",
+      "dpiMedium": "150 — Standard",
+      "dpiHigh": "200 — Bon",
+      "dpiUltra": "300 — Qualité d'impression"
+    },
+    "imagesToPdf": {
+      "title": "Images en PDF",
+      "description": "Combinez plusieurs images en un seul document PDF.",
+      "shortDesc": "Images → PDF",
+      "selectImages": "Sélectionner des images",
+      "addMore": "Ajouter plus d'images",
+      "imagesSelected": "{{count}} images sélectionnées"
+    },
+    "watermarkPdf": {
+      "title": "Filigrane PDF",
+      "description": "Ajoutez un filigrane de texte personnalisé à chaque page de votre PDF.",
+      "shortDesc": "Ajouter un filigrane",
+      "text": "Texte du filigrane",
+      "textPlaceholder": "Entrez le texte du filigrane",
+      "opacity": "Opacité",
+      "light": "Léger",
+      "heavy": "Dense"
+    },
+    "protectPdf": {
+      "title": "Protéger PDF",
+      "description": "Ajoutez une protection par mot de passe à votre PDF pour empêcher tout accès non autorisé.",
+      "shortDesc": "Protéger PDF",
+      "password": "Mot de passe",
+      "passwordPlaceholder": "Entrez un mot de passe fort",
+      "confirmPassword": "Confirmer le mot de passe",
+      "confirmPlaceholder": "Ressaisissez le mot de passe",
+      "mismatch": "Les mots de passe ne correspondent pas"
+    },
+    "unlockPdf": {
+      "title": "Déverrouiller PDF",
+      "description": "Supprimez la protection par mot de passe de votre fichier PDF.",
+      "shortDesc": "Déverrouiller PDF",
+      "password": "Mot de passe actuel",
+      "passwordPlaceholder": "Entrez le mot de passe du PDF"
+    },
+    "pageNumbers": {
+      "title": "Ajouter des numéros de page",
+      "description": "Ajoutez des numéros de page à chaque page de votre PDF. Choisissez la position et le numéro de début.",
+      "shortDesc": "Numéros de page",
+      "position": "Position du numéro",
+      "startNumber": "Commencer à partir de",
+      "bottomCenter": "Bas centre",
+      "bottomRight": "Bas droite",
+      "bottomLeft": "Bas gauche",
+      "topCenter": "Haut centre",
+      "topRight": "Haut droite",
+      "topLeft": "Haut gauche"
+    }
+  },
+  "result": {
+    "conversionComplete": "Conversion terminée !",
+    "compressionComplete": "Compression terminée !",
+    "originalSize": "Taille originale",
+    "newSize": "Nouvelle taille",
+    "reduction": "Réduction",
+    "downloadReady": "Votre fichier est prêt à être téléchargé.",
+    "linkExpiry": "Le lien de téléchargement expire dans 30 minutes."
+  }
+}
diff --git a/frontend/src/i18n/index.ts b/frontend/src/i18n/index.ts
index 7936a52..a90eff2 100644
--- a/frontend/src/i18n/index.ts
+++ b/frontend/src/i18n/index.ts
@@ -4,6 +4,7 @@ import LanguageDetector from 'i18next-browser-languagedetector';
 
 import en from './en.json';
 import ar from './ar.json';
+import fr from './fr.json';
 
 i18n
   .use(LanguageDetector)
@@ -12,9 +13,10 @@ i18n
     resources: {
       en: { translation: en },
       ar: { translation: ar },
+      fr: { translation: fr },
     },
     fallbackLng: 'en',
-    supportedLngs: ['en', 'ar'],
+    supportedLngs: ['en', 'ar', 'fr'],
     interpolation: {
       escapeValue: false,
     },
diff --git a/frontend/src/pages/HomePage.tsx b/frontend/src/pages/HomePage.tsx
index 120ab20..c5a7256 100644
--- a/frontend/src/pages/HomePage.tsx
+++ b/frontend/src/pages/HomePage.tsx
@@ -74,10 +74,10 @@ export default function HomePage() {
 
       {/* Hero Section */}
       <section className="py-12 text-center sm:py-16">
-        <h1 className="text-4xl font-bold tracking-tight text-slate-900 sm:text-5xl">
+        <h1 className="text-4xl font-bold tracking-tight text-slate-900 sm:text-5xl dark:text-white">
           {t('home.hero')}
         </h1>
-        <p className="mx-auto mt-4 max-w-xl text-lg text-slate-500">
+        <p className="mx-auto mt-4 max-w-xl text-lg text-slate-500 dark:text-slate-400">
           {t('home.heroSub')}
         </p>
       </section>
@@ -87,7 +87,7 @@ export default function HomePage() {
 
       {/* Tools Grid */}
       <section>
-        <h2 className="mb-6 text-center text-xl font-semibold text-slate-800">
+        <h2 className="mb-6 text-center text-xl font-semibold text-slate-800 dark:text-slate-200">
           {t('home.popularTools')}
         </h2>
         <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
diff --git a/frontend/src/styles/global.css b/frontend/src/styles/global.css
index b5bca3f..db36b67 100644
--- a/frontend/src/styles/global.css
+++ b/frontend/src/styles/global.css
@@ -11,12 +11,20 @@
     --color-border: #e2e8f0;
   }
 
+  .dark {
+    --color-bg: #0f172a;
+    --color-surface: #1e293b;
+    --color-text: #f1f5f9;
+    --color-text-secondary: #94a3b8;
+    --color-border: #334155;
+  }
+
   html {
     scroll-behavior: smooth;
   }
 
   body {
-    @apply bg-white text-slate-900 antialiased;
+    @apply bg-white text-slate-900 antialiased dark:bg-slate-950 dark:text-slate-100;
     font-family: 'Inter', 'Tajawal', system-ui, sans-serif;
   }
 
@@ -32,46 +40,46 @@
 
 @layer components {
   .btn-primary {
-    @apply inline-flex items-center justify-center gap-2 rounded-xl bg-primary-600 px-6 py-3 text-sm font-semibold text-white shadow-sm transition-all hover:bg-primary-700 focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-primary-600 disabled:opacity-50 disabled:cursor-not-allowed;
+    @apply inline-flex items-center justify-center gap-2 rounded-xl bg-primary-600 px-6 py-3 text-sm font-semibold text-white shadow-sm transition-all hover:bg-primary-700 focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-primary-600 disabled:opacity-50 disabled:cursor-not-allowed dark:bg-primary-500 dark:hover:bg-primary-600;
   }
 
   .btn-secondary {
-    @apply inline-flex items-center justify-center gap-2 rounded-xl bg-white px-6 py-3 text-sm font-semibold text-slate-900 shadow-sm ring-1 ring-inset ring-slate-300 transition-all hover:bg-slate-50 disabled:opacity-50 disabled:cursor-not-allowed;
+    @apply inline-flex items-center justify-center gap-2 rounded-xl bg-white px-6 py-3 text-sm font-semibold text-slate-900 shadow-sm ring-1 ring-inset ring-slate-300 transition-all hover:bg-slate-50 disabled:opacity-50 disabled:cursor-not-allowed dark:bg-slate-800 dark:text-slate-100 dark:ring-slate-600 dark:hover:bg-slate-700;
   }
 
   .btn-success {
-    @apply inline-flex items-center justify-center gap-2 rounded-xl bg-emerald-600 px-6 py-3 text-sm font-semibold text-white shadow-sm transition-all hover:bg-emerald-700 disabled:opacity-50 disabled:cursor-not-allowed;
+    @apply inline-flex items-center justify-center gap-2 rounded-xl bg-emerald-600 px-6 py-3 text-sm font-semibold text-white shadow-sm transition-all hover:bg-emerald-700 disabled:opacity-50 disabled:cursor-not-allowed dark:bg-emerald-500 dark:hover:bg-emerald-600;
   }
 
   .card {
-    @apply rounded-2xl bg-white p-6 shadow-sm ring-1 ring-slate-200 transition-shadow hover:shadow-md;
+    @apply rounded-2xl bg-white p-6 shadow-sm ring-1 ring-slate-200 transition-shadow hover:shadow-md dark:bg-slate-800 dark:ring-slate-700;
   }
 
   .tool-card {
-    @apply card cursor-pointer hover:ring-primary-300 hover:shadow-lg transition-all duration-200;
+    @apply card cursor-pointer hover:ring-primary-300 hover:shadow-lg transition-all duration-200 dark:hover:ring-primary-600;
   }
 
   .input-field {
-    @apply block w-full rounded-xl border-0 py-3 px-4 text-slate-900 shadow-sm ring-1 ring-inset ring-slate-300 placeholder:text-slate-400 focus:ring-2 focus:ring-inset focus:ring-primary-600 sm:text-sm sm:leading-6;
+    @apply block w-full rounded-xl border-0 py-3 px-4 text-slate-900 shadow-sm ring-1 ring-inset ring-slate-300 placeholder:text-slate-400 focus:ring-2 focus:ring-inset focus:ring-primary-600 sm:text-sm sm:leading-6 dark:bg-slate-800 dark:text-slate-100 dark:ring-slate-600 dark:placeholder:text-slate-500;
   }
 
   .section-heading {
-    @apply text-2xl font-bold tracking-tight text-slate-900 sm:text-3xl;
+    @apply text-2xl font-bold tracking-tight text-slate-900 sm:text-3xl dark:text-slate-100;
   }
 }
 
 /* Upload zone styles */
 .upload-zone {
-  @apply flex flex-col items-center justify-center rounded-2xl border-2 border-dashed border-slate-300 bg-slate-50 p-8 text-center transition-colors cursor-pointer;
+  @apply flex flex-col items-center justify-center rounded-2xl border-2 border-dashed border-slate-300 bg-slate-50 p-8 text-center transition-colors cursor-pointer dark:border-slate-600 dark:bg-slate-800/50;
 }
 
 .upload-zone:hover,
 .upload-zone.drag-active {
-  @apply border-primary-400 bg-primary-50;
+  @apply border-primary-400 bg-primary-50 dark:border-primary-500 dark:bg-primary-900/20;
 }
 
 .upload-zone.drag-active {
-  @apply ring-2 ring-primary-300;
+  @apply ring-2 ring-primary-300 dark:ring-primary-600;
 }
 
 /* Progress bar animation */
@@ -86,5 +94,21 @@
 
 /* Ad slot container */
 .ad-slot {
-  @apply flex items-center justify-center bg-slate-50 rounded-xl border border-slate-200 min-h-[90px] overflow-hidden;
+  @apply flex items-center justify-center bg-slate-50 rounded-xl border border-slate-200 min-h-[90px] overflow-hidden dark:bg-slate-800 dark:border-slate-700;
+}
+
+/* Dropdown animation */
+@keyframes fadeSlideIn {
+  from {
+    opacity: 0;
+    transform: translateY(-4px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
+
+.animate-in {
+  animation: fadeSlideIn 0.15s ease-out;
 }