Refactor to multi-category catalog with polished light mode

- Restructure from single filament table to multi-category product catalog
  (filamenti, stampaci, ploce, mlaznice, delovi, oprema)
- Add shared layout components (SiteHeader, SiteFooter, CategoryNav, Breadcrumb)
- Add reusable UI primitives (Badge, Button, Card, Modal, PriceDisplay, EmptyState)
- Add catalog components (CatalogPage, ProductTable, ProductGrid, FilamentCard, ProductCard)
- Add admin dashboard with sidebar navigation and category management
- Add product API endpoints and database migrations
- Add SEO pages (politika-privatnosti, uslovi-koriscenja, robots.txt, sitemap.xml)
- Fix light mode: gradient text contrast, category nav accessibility,
  surface tokens, card shadows, CTA section theming

app/upadaj/page.tsx

@@ -33,7 +33,7 @@ export default function AdminLogin() {
       trackEvent('Admin', 'Login', 'Success');
 
       // Redirect to admin dashboard using window.location for static export
-      window.location.href = '/dashboard';
+      window.location.href = '/upadaj/dashboard';
     } catch (err: any) {
       setError('Neispravno korisničko ime ili lozinka');
       console.error('Login error:', err);
@@ -44,28 +44,31 @@ export default function AdminLogin() {
   };
 
   return (
-    <div className="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-900 py-12 px-4 sm:px-6 lg:px-8">
+    <div className="min-h-screen flex items-center justify-center bg-[#060a14] py-12 px-4 sm:px-6 lg:px-8">
       <div className="max-w-md w-full space-y-8">
         <div className="flex flex-col items-center">
-          <img 
-            src="/logo.png" 
-            alt="Filamenteka" 
+          <img
+            src="/logo.png"
+            alt="Filamenteka"
             className="h-40 w-auto mb-6 drop-shadow-lg"
           />
-          <h2 className="text-center text-3xl font-extrabold text-gray-900 dark:text-white">
+          <h2
+            className="text-center text-3xl font-black text-white tracking-tight"
+            style={{ fontFamily: 'var(--font-display)' }}
+          >
             Admin Prijava
           </h2>
-          <p className="mt-2 text-center text-sm text-gray-600 dark:text-gray-400">
+          <p className="mt-2 text-center text-sm text-white/40">
             Prijavite se za upravljanje filamentima
           </p>
         </div>
         <form className="mt-8 space-y-6" onSubmit={handleLogin}>
           {error && (
-            <div className="rounded-md bg-red-50 dark:bg-red-900/20 p-4">
-              <p className="text-sm text-red-800 dark:text-red-400">{error}</p>
+            <div className="rounded-xl bg-red-500/10 border border-red-500/20 p-4">
+              <p className="text-sm text-red-400">{error}</p>
             </div>
           )}
-          <div className="rounded-md shadow-sm -space-y-px">
+          <div className="space-y-3">
             <div>
               <label htmlFor="username" className="sr-only">
                 Korisničko ime
@@ -76,7 +79,7 @@ export default function AdminLogin() {
                 type="text"
                 autoComplete="username"
                 required
-                className="appearance-none rounded-none relative block w-full px-3 py-2 border border-gray-300 dark:border-gray-700 placeholder-gray-500 dark:placeholder-gray-400 text-gray-900 dark:text-white rounded-t-md focus:outline-none focus:ring-blue-500 focus:border-blue-500 focus:z-10 sm:text-sm dark:bg-gray-800"
+                className="appearance-none relative block w-full px-4 py-3 border border-white/[0.08] placeholder-white/30 text-white rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500/40 focus:border-blue-500/40 sm:text-sm bg-white/[0.04]"
                 placeholder="Korisničko ime"
                 value={username}
                 onChange={(e) => setUsername(e.target.value)}
@@ -92,7 +95,7 @@ export default function AdminLogin() {
                 type="password"
                 autoComplete="current-password"
                 required
-                className="appearance-none rounded-none relative block w-full px-3 py-2 border border-gray-300 dark:border-gray-700 placeholder-gray-500 dark:placeholder-gray-400 text-gray-900 dark:text-white rounded-b-md focus:outline-none focus:ring-blue-500 focus:border-blue-500 focus:z-10 sm:text-sm dark:bg-gray-800"
+                className="appearance-none relative block w-full px-4 py-3 border border-white/[0.08] placeholder-white/30 text-white rounded-xl focus:outline-none focus:ring-2 focus:ring-blue-500/40 focus:border-blue-500/40 sm:text-sm bg-white/[0.04]"
                 placeholder="Lozinka"
                 value={password}
                 onChange={(e) => setPassword(e.target.value)}
@@ -104,7 +107,8 @@ export default function AdminLogin() {
             <button
               type="submit"
               disabled={loading}
-              className="group relative w-full flex justify-center py-2 px-4 border border-transparent text-sm font-medium rounded-md text-white bg-blue-600 hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 disabled:opacity-50 disabled:cursor-not-allowed"
+              className="group relative w-full flex justify-center py-3 px-4 border border-transparent text-sm font-semibold rounded-xl text-white bg-blue-600 hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+              style={{ boxShadow: '0 4px 14px rgba(59, 130, 246, 0.3)' }}
             >
               {loading ? 'Prijavljivanje...' : 'Prijavite se'}
             </button>
@@ -113,4 +117,4 @@ export default function AdminLogin() {
       </div>
     </div>
   );
-}
+}