Fix: Improve AuthForm design and add back button

Improved the design of the AuthForm to be more consistent with the rest of the project. Added a "back" button for users who do not want to log in or create an account.

Author: lovable-dev[bot]

src/components/AuthForm.tsx

@@ -7,7 +7,7 @@ import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/com
 import { Separator } from '@/components/ui/separator';
 import { useAuth } from '@/hooks/useAuth';
 import { useToast } from '@/hooks/use-toast';
-import { Chrome, Mail, Lock } from 'lucide-react';
+import { Chrome, Mail, Lock, ArrowLeft } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
 
 export const AuthForm = () => {
@@ -68,67 +68,87 @@ export const AuthForm = () => {
     }
   };
 
+  const handleBackToLanding = () => {
+    window.location.href = '/';
+  };
+
   return (
-    <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-blue-50 to-indigo-100 p-4">
-      <Card className="w-full max-w-md">
-        <CardHeader className="text-center">
-          <CardTitle className="text-2xl font-bold text-blue-600">{t('auth.title')}</CardTitle>
-          <CardDescription>
+    <div className="min-h-screen bg-gradient-to-br from-blue-50/50 via-white to-purple-50/50 flex items-center justify-center p-4 relative">
+      {/* Bouton retour */}
+      <Button
+        variant="ghost"
+        onClick={handleBackToLanding}
+        className="absolute top-6 left-6 text-slate-600 hover:text-slate-900"
+      >
+        <ArrowLeft className="mr-2 h-4 w-4" />
+        Retour
+      </Button>
+
+      <Card className="w-full max-w-md bg-white/80 backdrop-blur-sm border-slate-200/50 shadow-xl">
+        <CardHeader className="text-center pb-6">
+          <CardTitle className="text-2xl font-bold bg-gradient-to-r from-blue-600 to-purple-600 bg-clip-text text-transparent">
+            {t('auth.title')}
+          </CardTitle>
+          <CardDescription className="text-slate-600">
             {isLogin ? t('auth.loginDescription') : t('auth.signupDescription')}
           </CardDescription>
         </CardHeader>
-        <CardContent className="space-y-4">
+        <CardContent className="space-y-6">
           <Button
             variant="outline"
             onClick={handleGoogleSign}
             disabled={loading}
-            className="w-full"
+            className="w-full border-slate-200 hover:bg-slate-50 transition-colors"
           >
             <Chrome className="mr-2 h-4 w-4" />
             {t('auth.continueWithGoogle')}
           </Button>
 
           <div className="relative">
-            <Separator />
-            <span className="absolute left-1/2 top-1/2 -translate-x-1/2 -translate-y-1/2 bg-white px-2 text-sm text-muted-foreground">
+            <Separator className="bg-slate-200" />
+            <span className="absolute left-1/2 top-1/2 -translate-x-1/2 -translate-y-1/2 bg-white px-3 text-sm text-slate-500">
               {t('auth.or')}
             </span>
           </div>
 
           <form onSubmit={handleSubmit} className="space-y-4">
             <div className="space-y-2">
-              <Label htmlFor="email">{t('auth.email')}</Label>
+              <Label htmlFor="email" className="text-slate-700">{t('auth.email')}</Label>
               <div className="relative">
-                <Mail className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-muted-foreground" />
+                <Mail className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-slate-400" />
                 <Input
                   id="email"
                   type="email"
                   value={email}
                   onChange={(e) => setEmail(e.target.value)}
                   placeholder={t('auth.emailPlaceholder')}
-                  className="pl-10"
+                  className="pl-10 border-slate-200 focus:border-blue-500 focus:ring-blue-500"
                   required
                 />
               </div>
             </div>
 
             <div className="space-y-2">
-              <Label htmlFor="password">{t('auth.password')}</Label>
+              <Label htmlFor="password" className="text-slate-700">{t('auth.password')}</Label>
               <div className="relative">
-                <Lock className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-muted-foreground" />
+                <Lock className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-slate-400" />
                 <Input
                   id="password"
                   type="password"
                   value={password}
                   onChange={(e) => setPassword(e.target.value)}
                   placeholder={t('auth.passwordPlaceholder')}
-                  className="pl-10"
+                  className="pl-10 border-slate-200 focus:border-blue-500 focus:ring-blue-500"
                   required
                 />
               </div>
             </div>
 
-            <Button type="submit" className="w-full" disabled={loading}>
+            <Button 
+              type="submit" 
+              className="w-full bg-gradient-to-r from-blue-600 to-purple-600 hover:from-blue-700 hover:to-purple-700 text-white border-0 shadow-lg hover:shadow-xl transition-all duration-200" 
+              disabled={loading}
+            >
               {loading ? t('auth.loading') : (isLogin ? t('auth.signIn') : t('auth.signUp'))}
             </Button>
           </form>
@@ -137,7 +157,7 @@ export const AuthForm = () => {
             <Button
               variant="link"
               onClick={() => setIsLogin(!isLogin)}
-              className="text-sm"
+              className="text-sm text-slate-600 hover:text-slate-900"
             >
               {isLogin ? t('auth.noAccount') : t('auth.hasAccount')}
             </Button>