feat: Integrate shadcn/ui design system

- Install shadcn/ui dependencies (CVA, clsx, tailwind-merge, lucide-react)
- Install Radix UI primitives (slot, label)
- Create utility helper (lib/utils.ts with cn function)
- Update Tailwind config for shadcn/ui theme support
- Add CSS variables for theming in globals.css (Tailwind v4 syntax)
- Add shadcn/ui components: Button, Card, Input, Label
- Update JourneyForm with shadcn/ui components and icons
- Update DataPreview with shadcn/ui components and icons
- Improve UI consistency and accessibility

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/app/components/DataPreview.tsx

@@ -2,6 +2,9 @@
 
 import { useState } from 'react'
 import API_URL from '@/lib/api'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import { Upload, BarChart3, Loader2, FileText, CheckCircle2, AlertCircle } from 'lucide-react'
 
 interface DataPreviewProps {
   data: any
@@ -53,63 +56,54 @@ export default function DataPreview({ data, loading, formData }: DataPreviewProp
   }
   if (loading) {
     return (
-      <div className="bg-white/98 backdrop-blur-lg rounded-3xl shadow-2xl border border-white/30 overflow-hidden">
-        <div className="flex flex-col items-center justify-center h-96 p-8">
-          <div className="relative">
-            <div className="animate-spin rounded-full h-20 w-20 border-4 border-blue-200"></div>
-            <div className="animate-spin rounded-full h-20 w-20 border-t-4 border-blue-600 absolute top-0"></div>
-          </div>
+      <Card className="bg-white/98 backdrop-blur-lg border-white/30">
+        <CardContent className="flex flex-col items-center justify-center h-96 p-8">
+          <Loader2 className="h-20 w-20 text-blue-600 animate-spin" />
           <p className="mt-6 text-gray-700 font-semibold text-lg">Načítání dat...</p>
-        </div>
-      </div>
+        </CardContent>
+      </Card>
     )
   }
 
   if (!data) {
     return (
-      <div className="bg-white/98 backdrop-blur-lg rounded-3xl shadow-2xl border border-white/30 overflow-hidden">
-        <div className="bg-gradient-to-r from-purple-50 to-purple-100 px-8 py-6 border-b border-purple-200">
-          <div className="flex items-center gap-4">
+      <Card className="bg-white/98 backdrop-blur-lg border-white/30">
+        <CardHeader className="bg-gradient-to-r from-purple-50 to-purple-100 border-b border-purple-200">
+          <CardTitle className="text-3xl font-bold text-gray-800 flex items-center gap-4">
             <div className="w-12 h-12 bg-gradient-to-br from-purple-500 to-purple-600 rounded-xl flex items-center justify-center shadow-lg">
-              <svg className="w-7 h-7 text-white" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 19v-6a2 2 0 00-2-2H5a2 2 0 00-2 2v6a2 2 0 002 2h2a2 2 0 002-2zm0 0V9a2 2 0 012-2h2a2 2 0 012 2v10m-6 0a2 2 0 002 2h2a2 2 0 002-2m0 0V5a2 2 0 012-2h2a2 2 0 012 2v14a2 2 0 01-2 2h-2a2 2 0 01-2-2z" />
-              </svg>
+              <BarChart3 className="w-7 h-7 text-white" />
             </div>
-            <h2 className="text-3xl font-bold text-gray-800">Náhled dat</h2>
+            <span>Náhled dat</span>
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="p-8">
+          <div className="flex flex-col items-center justify-center py-16 text-center">
+            <div className="w-20 h-20 bg-gray-100 rounded-full flex items-center justify-center mb-4">
+              <FileText className="w-10 h-10 text-gray-400" />
+            </div>
+            <p className="text-gray-500 font-medium">
+              Vyplňte formulář a klikněte na "Vypočítat"
+            </p>
+            <p className="text-gray-400 text-sm mt-1">
+              Data se zobrazí zde
+            </p>
           </div>
-        </div>
-        <div className="p-8">
-        <div className="flex flex-col items-center justify-center py-16 text-center">
-          <div className="w-20 h-20 bg-gray-100 rounded-full flex items-center justify-center mb-4">
-            <svg className="w-10 h-10 text-gray-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M7 21h10a2 2 0 002-2V9.414a1 1 0 00-.293-.707l-5.414-5.414A1 1 0 0012.586 3H7a2 2 0 00-2 2v14a2 2 0 002 2z" />
-            </svg>
-          </div>
-          <p className="text-gray-500 font-medium">
-            Vyplňte formulář a klikněte na "Vypočítat"
-          </p>
-          <p className="text-gray-400 text-sm mt-1">
-            Data se zobrazí zde
-          </p>
-        </div>
-        </div>
-      </div>
+        </CardContent>
+      </Card>
     )
   }
 
   return (
-    <div className="bg-white/98 backdrop-blur-lg rounded-3xl shadow-2xl border border-white/30 overflow-hidden">
-      <div className="bg-gradient-to-r from-purple-50 to-purple-100 px-8 py-6 border-b border-purple-200">
-        <div className="flex items-center gap-4">
+    <Card className="bg-white/98 backdrop-blur-lg border-white/30">
+      <CardHeader className="bg-gradient-to-r from-purple-50 to-purple-100 border-b border-purple-200">
+        <CardTitle className="text-3xl font-bold text-gray-800 flex items-center gap-4">
           <div className="w-12 h-12 bg-gradient-to-br from-purple-500 to-purple-600 rounded-xl flex items-center justify-center shadow-lg">
-            <svg className="w-7 h-7 text-white" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 19v-6a2 2 0 00-2-2H5a2 2 0 00-2 2v6a2 2 0 002 2h2a2 2 0 002-2zm0 0V9a2 2 0 012-2h2a2 2 0 012 2v10m-6 0a2 2 0 002 2h2a2 2 0 002-2m0 0V5a2 2 0 012-2h2a2 2 0 012 2v14a2 2 0 01-2 2h-2a2 2 0 01-2-2z" />
-            </svg>
+            <BarChart3 className="w-7 h-7 text-white" />
           </div>
-          <h2 className="text-3xl font-bold text-gray-800">Náhled dat</h2>
-        </div>
-      </div>
-      <div className="p-8">
+          <span>Náhled dat</span>
+        </CardTitle>
+      </CardHeader>
+      <CardContent className="p-8">
 
       <div className="mb-6 grid grid-cols-2 gap-3 bg-gradient-to-br from-blue-50 to-indigo-50 p-5 rounded-xl border border-blue-100">
         <div>
@@ -165,23 +159,39 @@ export default function DataPreview({ data, loading, formData }: DataPreviewProp
 
       {formData && formData.startDate === '2025-01-01' && (
         <div className="mt-6">
-          <button
+          <Button
             onClick={handleFillToWebsite}
             disabled={filling}
-            className="w-full bg-gradient-to-r from-orange-600 to-orange-700 hover:from-orange-700 hover:to-orange-800 text-white font-bold py-4 px-6 rounded-xl shadow-lg hover:shadow-2xl transform hover:-translate-y-1 transition-all duration-200 disabled:opacity-50 disabled:cursor-not-allowed"
+            size="lg"
+            className="w-full bg-gradient-to-r from-orange-600 to-orange-700 hover:from-orange-700 hover:to-orange-800 text-lg h-12"
           >
-            <span className="flex items-center justify-center gap-3">
-              <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-8l-4-4m0 0L8 8m4-4v12" />
-              </svg>
-              <span className="text-lg">{filling ? 'Vyplňování...' : 'Vyplnit na web'}</span>
-            </span>
-          </button>
+            {filling ? (
+              <>
+                <Loader2 className="mr-2 h-5 w-5 animate-spin" />
+                Vyplňování...
+              </>
+            ) : (
+              <>
+                <Upload className="mr-2 h-5 w-5" />
+                Vyplnit na web
+              </>
+            )}
+          </Button>
 
           {fillResult && (
             <div className={`mt-4 ${fillResult.dry_run ? 'bg-blue-50 border-blue-200' : 'bg-green-50 border-green-200'} border rounded-xl p-4`}>
-              <h3 className={`font-bold ${fillResult.dry_run ? 'text-blue-900' : 'text-green-900'} mb-2`}>
-                {fillResult.dry_run ? 'Výsledek DRY RUN:' : 'Výsledek vyplňování:'}
+              <h3 className={`font-bold ${fillResult.dry_run ? 'text-blue-900' : 'text-green-900'} mb-2 flex items-center gap-2`}>
+                {fillResult.dry_run ? (
+                  <>
+                    <AlertCircle className="h-5 w-5" />
+                    Výsledek DRY RUN:
+                  </>
+                ) : (
+                  <>
+                    <CheckCircle2 className="h-5 w-5" />
+                    Výsledek vyplňování:
+                  </>
+                )}
               </h3>
               <div className={`text-sm ${fillResult.dry_run ? 'text-blue-800' : 'text-green-800'}`}>
                 <p>Měsíc: {fillResult.month}</p>
@@ -205,18 +215,23 @@ export default function DataPreview({ data, loading, formData }: DataPreviewProp
                   </>
                 )}
                 {fillResult.dry_run && (
-                  <p className="mt-2 font-semibold text-orange-700">
-                    ⚠️ DRY RUN MODE - Data nebyla odeslána na web
+                  <p className="mt-2 font-semibold text-orange-700 flex items-center gap-2">
+                    <AlertCircle className="h-4 w-4" />
+                    DRY RUN MODE - Data nebyla odeslána na web
                   </p>
                 )}
                 {!fillResult.dry_run && fillResult.updates_successful > 0 && (
-                  <p className="mt-2 font-semibold text-green-700">
-                    ✅ Data byla úspěšně vyplněna. Nyní zkontrolujte na webu a klikněte "Uzavřít měsíc" ručně.
+                  <p className="mt-2 font-semibold text-green-700 flex items-center gap-2">
+                    <CheckCircle2 className="h-4 w-4" />
+                    Data byla úspěšně vyplněna. Nyní zkontrolujte na webu a klikněte "Uzavřít měsíc" ručně.
                   </p>
                 )}
                 {!fillResult.dry_run && fillResult.errors && fillResult.errors.length > 0 && (
                   <div className="mt-2 p-2 bg-red-100 border border-red-300 rounded">
-                    <p className="font-semibold text-red-900">Chyby:</p>
+                    <p className="font-semibold text-red-900 flex items-center gap-2">
+                      <AlertCircle className="h-4 w-4" />
+                      Chyby:
+                    </p>
                     {fillResult.errors.map((err: any, idx: number) => (
                       <p key={idx} className="text-xs text-red-800">• {err.type} řádek {err.row}: {err.error}</p>
                     ))}
@@ -227,7 +242,7 @@ export default function DataPreview({ data, loading, formData }: DataPreviewProp
           )}
         </div>
       )}
-      </div>
-    </div>
+      </CardContent>
+    </Card>
   )
 }

frontend/app/components/JourneyForm.tsx

@@ -2,6 +2,11 @@
 
 import { useState } from 'react'
 import API_URL from '@/lib/api'
+import { Button } from '@/components/ui/button'
+import { Input } from '@/components/ui/input'
+import { Label } from '@/components/ui/label'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import { Calculator, Download } from 'lucide-react'
 
 interface JourneyFormProps {
   onDataCalculated: (data: any) => void
@@ -99,130 +104,114 @@ export default function JourneyForm({ onDataCalculated, setLoading, onFormDataCh
   }
 
   return (
-    <div className="bg-white/98 backdrop-blur-lg rounded-3xl shadow-2xl overflow-hidden border border-white/30">
-      <div className="bg-gradient-to-r from-blue-50 to-blue-100 px-8 py-6 border-b border-blue-200">
-        <div className="flex items-center gap-4">
+    <Card className="bg-white/98 backdrop-blur-lg border-white/30">
+      <CardHeader className="bg-gradient-to-r from-blue-50 to-blue-100 border-b border-blue-200">
+        <CardTitle className="text-3xl font-bold text-gray-800 flex items-center gap-4">
           <div className="w-12 h-12 bg-gradient-to-br from-blue-500 to-blue-600 rounded-xl flex items-center justify-center shadow-lg">
             <svg className="w-7 h-7 text-white" fill="none" stroke="currentColor" viewBox="0 0 24 24">
               <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z" />
             </svg>
           </div>
-          <h2 className="text-3xl font-bold text-gray-800">Vstupní údaje</h2>
-        </div>
-      </div>
-      <div className="p-8">
+          <span>Vstupní údaje</span>
+        </CardTitle>
+      </CardHeader>
+      <CardContent className="p-8">
 
       <form onSubmit={handleSubmit} className="space-y-5">
-        <div>
-          <label className="block text-sm font-medium text-gray-700 mb-1">
-            Uživatelské jméno
-          </label>
-          <input
+        <div className="space-y-2">
+          <Label htmlFor="username">Uživatelské jméno</Label>
+          <Input
+            id="username"
             type="text"
             required
             value={formData.username}
             onChange={(e) => setFormData({ ...formData, username: e.target.value })}
-            className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
             placeholder="Zadejte uživatelské jméno"
           />
         </div>
 
-        <div>
-          <label className="block text-sm font-medium text-gray-700 mb-1">
-            Heslo
-          </label>
-          <input
+        <div className="space-y-2">
+          <Label htmlFor="password">Heslo</Label>
+          <Input
+            id="password"
             type="password"
             required
             value={formData.password}
             onChange={(e) => setFormData({ ...formData, password: e.target.value })}
-            className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
             placeholder="Zadejte heslo"
           />
         </div>
 
         <div className="grid grid-cols-2 gap-4">
-          <div>
-            <label className="block text-sm font-medium text-gray-700 mb-1">
-              Datum od
-            </label>
-            <input
+          <div className="space-y-2">
+            <Label htmlFor="startDate">Datum od</Label>
+            <Input
+              id="startDate"
               type="date"
               required
               value={formData.startDate}
               onChange={(e) => setFormData({ ...formData, startDate: e.target.value })}
-              className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
             />
           </div>
 
-          <div>
-            <label className="block text-sm font-medium text-gray-700 mb-1">
-              Datum do
-            </label>
-            <input
+          <div className="space-y-2">
+            <Label htmlFor="endDate">Datum do</Label>
+            <Input
+              id="endDate"
               type="date"
               required
               value={formData.endDate}
               onChange={(e) => setFormData({ ...formData, endDate: e.target.value })}
-              className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
             />
           </div>
         </div>
 
         <div className="grid grid-cols-2 gap-4">
-          <div>
-            <label className="block text-sm font-medium text-gray-700 mb-1">
-              Počáteční stav [km]
-            </label>
-            <input
+          <div className="space-y-2">
+            <Label htmlFor="startKm">Počáteční stav [km]</Label>
+            <Input
+              id="startKm"
               type="number"
               required
               value={formData.startKm}
               onChange={(e) => setFormData({ ...formData, startKm: e.target.value })}
-              className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
             />
           </div>
 
-          <div>
-            <label className="block text-sm font-medium text-gray-700 mb-1">
-              Koncový stav [km]
-            </label>
-            <input
+          <div className="space-y-2">
+            <Label htmlFor="endKm">Koncový stav [km]</Label>
+            <Input
+              id="endKm"
               type="number"
               required
               value={formData.endKm}
               onChange={(e) => setFormData({ ...formData, endKm: e.target.value })}
-              className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
             />
           </div>
         </div>
 
-        <div>
-          <label className="block text-sm font-medium text-gray-700 mb-1">
-            SPZ vozidla
-          </label>
-          <input
+        <div className="space-y-2">
+          <Label htmlFor="vehicleRegistration">SPZ vozidla</Label>
+          <Input
+            id="vehicleRegistration"
             type="text"
             value={formData.vehicleRegistration}
             onChange={(e) => setFormData({ ...formData, vehicleRegistration: e.target.value })}
-            className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
           />
         </div>
 
-        <div>
-          <label className="block text-sm font-medium text-gray-700 mb-1">
-            Variance (0-1)
-          </label>
-          <input
+        <div className="space-y-2">
+          <Label htmlFor="variance">Variance (0-1)</Label>
+          <Input
+            id="variance"
             type="number"
             step="0.01"
             min="0"
             max="1"
             value={formData.variance}
             onChange={(e) => setFormData({ ...formData, variance: e.target.value })}
-            className="w-full px-4 py-3 bg-gray-50 border border-gray-200 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
           />
-          <p className="text-xs text-gray-500 mt-1">
+          <p className="text-xs text-muted-foreground">
             Náhodná variace rozdělení kilometrů (doporučeno 0.1 = 10%)
           </p>
         </div>
@@ -237,33 +226,27 @@ export default function JourneyForm({ onDataCalculated, setLoading, onFormDataCh
         )}
 
         <div className="flex flex-col sm:flex-row gap-4 pt-6">
-          <button
+          <Button
             type="submit"
-            className="flex-1 bg-gradient-to-r from-blue-600 to-blue-700 hover:from-blue-700 hover:to-blue-800 text-white font-bold py-4 px-6 rounded-xl shadow-lg hover:shadow-2xl transform hover:-translate-y-1 transition-all duration-200"
+            size="lg"
+            className="flex-1 bg-gradient-to-r from-blue-600 to-blue-700 hover:from-blue-700 hover:to-blue-800 text-lg h-12"
           >
-            <span className="flex items-center justify-center gap-3">
-              <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 7h6m0 10v-3m-3 3h.01M9 17h.01M9 14h.01M12 14h.01M15 11h.01M12 11h.01M9 11h.01M7 21h10a2 2 0 002-2V5a2 2 0 00-2-2H7a2 2 0 00-2 2v14a2 2 0 002 2z" />
-              </svg>
-              <span className="text-lg">Vypočítat</span>
-            </span>
-          </button>
+            <Calculator className="mr-2 h-5 w-5" />
+            Vypočítat
+          </Button>
 
-          <button
+          <Button
             type="button"
             onClick={handleExport}
-            className="flex-1 bg-gradient-to-r from-green-600 to-green-700 hover:from-green-700 hover:to-green-800 text-white font-bold py-4 px-6 rounded-xl shadow-lg hover:shadow-2xl transform hover:-translate-y-1 transition-all duration-200"
+            size="lg"
+            className="flex-1 bg-gradient-to-r from-green-600 to-green-700 hover:from-green-700 hover:to-green-800 text-lg h-12"
           >
-            <span className="flex items-center justify-center gap-3">
-              <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 10v6m0 0l-3-3m3 3l3-3m2 8H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
-              </svg>
-              <span className="text-lg">Export Excel</span>
-            </span>
-          </button>
+            <Download className="mr-2 h-5 w-5" />
+            Export Excel
+          </Button>
         </div>
       </form>
-      </div>
-    </div>
+      </CardContent>
+    </Card>
   )
 }

frontend/app/globals.css

@@ -1,9 +1,26 @@
 @import "tailwindcss";
 
 @theme {
-  --color-primary: #2563eb;
-  --color-primary-dark: #1d4ed8;
-  --radius-card: 12px;
+  --color-background: 0 0% 100%;
+  --color-foreground: 222.2 84% 4.9%;
+  --color-card: 0 0% 100%;
+  --color-card-foreground: 222.2 84% 4.9%;
+  --color-popover: 0 0% 100%;
+  --color-popover-foreground: 222.2 84% 4.9%;
+  --color-primary: 221.2 83.2% 53.3%;
+  --color-primary-foreground: 210 40% 98%;
+  --color-secondary: 210 40% 96.1%;
+  --color-secondary-foreground: 222.2 47.4% 11.2%;
+  --color-muted: 210 40% 96.1%;
+  --color-muted-foreground: 215.4 16.3% 46.9%;
+  --color-accent: 210 40% 96.1%;
+  --color-accent-foreground: 222.2 47.4% 11.2%;
+  --color-destructive: 0 84.2% 60.2%;
+  --color-destructive-foreground: 210 40% 98%;
+  --color-border: 214.3 31.8% 91.4%;
+  --color-input: 214.3 31.8% 91.4%;
+  --color-ring: 221.2 83.2% 53.3%;
+  --radius: 0.5rem;
 }
 
 * {
@@ -16,5 +33,5 @@ body {
   font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
   background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
   min-height: 100vh;
-  color: #1f2937;
+  color: hsl(var(--color-foreground));
 }

frontend/components.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "default",
+  "rsc": true,
+  "tsx": true,
+  "tailwind": {
+    "config": "tailwind.config.js",
+    "css": "app/globals.css",
+    "baseColor": "slate",
+    "cssVariables": true,
+    "prefix": ""
+  },
+  "aliases": {
+    "components": "@/components",
+    "utils": "@/lib/utils"
+  }
+}

frontend/components/ui/button.tsx

@@ -0,0 +1,57 @@
+import * as React from "react"
+import { Slot } from "@radix-ui/react-slot"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+
+const buttonVariants = cva(
+  "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0",
+  {
+    variants: {
+      variant: {
+        default:
+          "bg-primary text-primary-foreground shadow hover:bg-primary/90",
+        destructive:
+          "bg-destructive text-destructive-foreground shadow-sm hover:bg-destructive/90",
+        outline:
+          "border border-input bg-background shadow-sm hover:bg-accent hover:text-accent-foreground",
+        secondary:
+          "bg-secondary text-secondary-foreground shadow-sm hover:bg-secondary/80",
+        ghost: "hover:bg-accent hover:text-accent-foreground",
+        link: "text-primary underline-offset-4 hover:underline",
+      },
+      size: {
+        default: "h-9 px-4 py-2",
+        sm: "h-8 rounded-md px-3 text-xs",
+        lg: "h-10 rounded-md px-8",
+        icon: "h-9 w-9",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+      size: "default",
+    },
+  }
+)
+
+export interface ButtonProps
+  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
+    VariantProps<typeof buttonVariants> {
+  asChild?: boolean
+}
+
+const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
+  ({ className, variant, size, asChild = false, ...props }, ref) => {
+    const Comp = asChild ? Slot : "button"
+    return (
+      <Comp
+        className={cn(buttonVariants({ variant, size, className }))}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Button.displayName = "Button"
+
+export { Button, buttonVariants }

frontend/components/ui/card.tsx

@@ -0,0 +1,76 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+const Card = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div
+    ref={ref}
+    className={cn(
+      "rounded-xl border bg-card text-card-foreground shadow",
+      className
+    )}
+    {...props}
+  />
+))
+Card.displayName = "Card"
+
+const CardHeader = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div
+    ref={ref}
+    className={cn("flex flex-col space-y-1.5 p-6", className)}
+    {...props}
+  />
+))
+CardHeader.displayName = "CardHeader"
+
+const CardTitle = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div
+    ref={ref}
+    className={cn("font-semibold leading-none tracking-tight", className)}
+    {...props}
+  />
+))
+CardTitle.displayName = "CardTitle"
+
+const CardDescription = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div
+    ref={ref}
+    className={cn("text-sm text-muted-foreground", className)}
+    {...props}
+  />
+))
+CardDescription.displayName = "CardDescription"
+
+const CardContent = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div ref={ref} className={cn("p-6 pt-0", className)} {...props} />
+))
+CardContent.displayName = "CardContent"
+
+const CardFooter = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div
+    ref={ref}
+    className={cn("flex items-center p-6 pt-0", className)}
+    {...props}
+  />
+))
+CardFooter.displayName = "CardFooter"
+
+export { Card, CardHeader, CardFooter, CardTitle, CardDescription, CardContent }

frontend/components/ui/input.tsx

@@ -0,0 +1,22 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+const Input = React.forwardRef<HTMLInputElement, React.ComponentProps<"input">>(
+  ({ className, type, ...props }, ref) => {
+    return (
+      <input
+        type={type}
+        className={cn(
+          "flex h-9 w-full rounded-md border border-input bg-transparent px-3 py-1 text-base shadow-sm transition-colors file:border-0 file:bg-transparent file:text-sm file:font-medium file:text-foreground placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50 md:text-sm",
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Input.displayName = "Input"
+
+export { Input }

frontend/components/ui/label.tsx

@@ -0,0 +1,24 @@
+import * as React from "react"
+import * as LabelPrimitive from "@radix-ui/react-label"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+
+const labelVariants = cva(
+  "text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70"
+)
+
+const Label = React.forwardRef<
+  React.ElementRef<typeof LabelPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof LabelPrimitive.Root> &
+    VariantProps<typeof labelVariants>
+>(({ className, ...props }, ref) => (
+  <LabelPrimitive.Root
+    ref={ref}
+    className={cn(labelVariants(), className)}
+    {...props}
+  />
+))
+Label.displayName = LabelPrimitive.Root.displayName
+
+export { Label }

frontend/lib/utils.ts

@@ -0,0 +1,6 @@
+import { type ClassValue, clsx } from "clsx"
+import { twMerge } from "tailwind-merge"
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}

frontend/package-lock.json

@@ -9,14 +9,20 @@
       "version": "1.0.0",
       "license": "ISC",
       "dependencies": {
+        "@radix-ui/react-label": "^2.1.7",
+        "@radix-ui/react-slot": "^1.2.3",
         "@tailwindcss/postcss": "^4.1.14",
         "@types/node": "^24.7.1",
         "@types/react": "^19.2.2",
         "autoprefixer": "^10.4.21",
+        "class-variance-authority": "^0.7.1",
+        "clsx": "^2.1.1",
+        "lucide-react": "^0.545.0",
         "next": "^15.5.4",
         "postcss": "^8.5.6",
         "react": "^19.2.0",
         "react-dom": "^19.2.0",
+        "tailwind-merge": "^3.3.1",
         "tailwindcss": "^4.1.14",
         "typescript": "^5.9.3"
       }
@@ -662,6 +668,85 @@
         "node": ">= 10"
       }
     },
+    "node_modules/@radix-ui/react-compose-refs": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-compose-refs/-/react-compose-refs-1.1.2.tgz",
+      "integrity": "sha512-z4eqJvfiNnFMHIIvXP3CY57y2WJs5g2v3X0zm9mEJkrkNv4rDxu+sg9Jh8EkXyeqBkB7SOcboo9dMVqhyrACIg==",
+      "license": "MIT",
+      "peerDependencies": {
+        "@types/react": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@radix-ui/react-label": {
+      "version": "2.1.7",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-label/-/react-label-2.1.7.tgz",
+      "integrity": "sha512-YT1GqPSL8kJn20djelMX7/cTRp/Y9w5IZHvfxQTVHrOqa2yMl7i/UfMqKRU5V7mEyKTrUVgJXhNQPVCG8PBLoQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/react-primitive": "2.1.3"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@radix-ui/react-primitive": {
+      "version": "2.1.3",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-primitive/-/react-primitive-2.1.3.tgz",
+      "integrity": "sha512-m9gTwRkhy2lvCPe6QJp4d3G1TYEUHn/FzJUtq9MjH46an1wJU+GdoGC5VLof8RX8Ft/DlpshApkhswDLZzHIcQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/react-slot": "1.2.3"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@radix-ui/react-slot": {
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-slot/-/react-slot-1.2.3.tgz",
+      "integrity": "sha512-aeNmHnBxbi2St0au6VBVC7JXFlhLlOnvIIlePNniyUNAClzmtAUEY8/pBiK3iHjufOlwA+c20/8jngo7xcrg8A==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/react-compose-refs": "1.1.2"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@swc/helpers": {
       "version": "0.5.15",
       "resolved": "https://registry.npmjs.org/@swc/helpers/-/helpers-0.5.15.tgz",
@@ -1058,12 +1143,33 @@
         "node": ">=18"
       }
     },
+    "node_modules/class-variance-authority": {
+      "version": "0.7.1",
+      "resolved": "https://registry.npmjs.org/class-variance-authority/-/class-variance-authority-0.7.1.tgz",
+      "integrity": "sha512-Ka+9Trutv7G8M6WT6SeiRWz792K5qEqIGEGzXKhAE6xOWAY6pPH8U+9IY3oCMv6kqTmLsv7Xh/2w2RigkePMsg==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "clsx": "^2.1.1"
+      },
+      "funding": {
+        "url": "https://polar.sh/cva"
+      }
+    },
     "node_modules/client-only": {
       "version": "0.0.1",
       "resolved": "https://registry.npmjs.org/client-only/-/client-only-0.0.1.tgz",
       "integrity": "sha512-IV3Ou0jSMzZrd3pZ48nLkT9DA7Ag1pnPzaiQhpW7c3RbcqqzvzzVu+L8gfqMp/8IM2MQtSiqaCxrrcfu8I8rMA==",
       "license": "MIT"
     },
+    "node_modules/clsx": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/clsx/-/clsx-2.1.1.tgz",
+      "integrity": "sha512-eYm0QWBtUrBWZWG0d386OGAw16Z995PiOVo2B7bjWSbHedGl5e0ZWaq65kOGgUSNesEIDkB9ISbTg/JK9dhCZA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=6"
+      }
+    },
     "node_modules/csstype": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/csstype/-/csstype-3.1.3.tgz",
@@ -1363,6 +1469,15 @@
         "url": "https://opencollective.com/parcel"
       }
     },
+    "node_modules/lucide-react": {
+      "version": "0.545.0",
+      "resolved": "https://registry.npmjs.org/lucide-react/-/lucide-react-0.545.0.tgz",
+      "integrity": "sha512-7r1/yUuflQDSt4f1bpn5ZAocyIxcTyVyBBChSVtBKn5M+392cPmI5YJMWOJKk/HUWGm5wg83chlAZtCcGbEZtw==",
+      "license": "ISC",
+      "peerDependencies": {
+        "react": "^16.5.1 || ^17.0.0 || ^18.0.0 || ^19.0.0"
+      }
+    },
     "node_modules/magic-string": {
       "version": "0.30.19",
       "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.19.tgz",
@@ -1661,6 +1776,16 @@
         }
       }
     },
+    "node_modules/tailwind-merge": {
+      "version": "3.3.1",
+      "resolved": "https://registry.npmjs.org/tailwind-merge/-/tailwind-merge-3.3.1.tgz",
+      "integrity": "sha512-gBXpgUm/3rp1lMZZrM/w7D8GKqshif0zAymAhbCyIt8KMe+0v9DQ7cdYLR4FHH/cKpdTXb+A/tKKU3eolfsI+g==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/dcastil"
+      }
+    },
     "node_modules/tailwindcss": {
       "version": "4.1.14",
       "resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.1.14.tgz",

frontend/package.json

@@ -13,14 +13,20 @@
   "license": "ISC",
   "description": "",
   "dependencies": {
+    "@radix-ui/react-label": "^2.1.7",
+    "@radix-ui/react-slot": "^1.2.3",
     "@tailwindcss/postcss": "^4.1.14",
     "@types/node": "^24.7.1",
     "@types/react": "^19.2.2",
     "autoprefixer": "^10.4.21",
+    "class-variance-authority": "^0.7.1",
+    "clsx": "^2.1.1",
+    "lucide-react": "^0.545.0",
     "next": "^15.5.4",
     "postcss": "^8.5.6",
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
+    "tailwind-merge": "^3.3.1",
     "tailwindcss": "^4.1.14",
     "typescript": "^5.9.3"
   }

frontend/tailwind.config.js

@@ -6,7 +6,48 @@ module.exports = {
     './app/**/*.{js,ts,jsx,tsx,mdx}',
   ],
   theme: {
-    extend: {},
+    extend: {
+      colors: {
+        border: "hsl(var(--color-border))",
+        input: "hsl(var(--color-input))",
+        ring: "hsl(var(--color-ring))",
+        background: "hsl(var(--color-background))",
+        foreground: "hsl(var(--color-foreground))",
+        primary: {
+          DEFAULT: "hsl(var(--color-primary))",
+          foreground: "hsl(var(--color-primary-foreground))",
+        },
+        secondary: {
+          DEFAULT: "hsl(var(--color-secondary))",
+          foreground: "hsl(var(--color-secondary-foreground))",
+        },
+        destructive: {
+          DEFAULT: "hsl(var(--color-destructive))",
+          foreground: "hsl(var(--color-destructive-foreground))",
+        },
+        muted: {
+          DEFAULT: "hsl(var(--color-muted))",
+          foreground: "hsl(var(--color-muted-foreground))",
+        },
+        accent: {
+          DEFAULT: "hsl(var(--color-accent))",
+          foreground: "hsl(var(--color-accent-foreground))",
+        },
+        popover: {
+          DEFAULT: "hsl(var(--color-popover))",
+          foreground: "hsl(var(--color-popover-foreground))",
+        },
+        card: {
+          DEFAULT: "hsl(var(--color-card))",
+          foreground: "hsl(var(--color-card-foreground))",
+        },
+      },
+      borderRadius: {
+        lg: "var(--radius)",
+        md: "calc(var(--radius) - 2px)",
+        sm: "calc(var(--radius) - 4px)",
+      },
+    },
   },
   plugins: [],
 }