Improve admin panel and sale countdown banner

- Remove 'apply to all' option from sale manager - only selected items
- Fix PLA Translucent to be spool-only (no refill option)
- Sale countdown shows actual max percentage from database
- Update banner design: blue-purple-orange gradient instead of red
- Remove fire emoji and promotional text
- Make percentage number larger and yellow for emphasis
- Change 'do' to 'od' in discount text
- Add shimmer animation for subtle effect

src/components/SaleCountdown.tsx

@@ -9,7 +9,12 @@ interface TimeLeft {
   seconds: number;
 }
 
-export function SaleCountdown() {
+interface SaleCountdownProps {
+  hasActiveSale: boolean;
+  maxSalePercentage?: number;
+}
+
+export function SaleCountdown({ hasActiveSale, maxSalePercentage = 5 }: SaleCountdownProps) {
   const [timeLeft, setTimeLeft] = useState<TimeLeft>({ days: 0, hours: 0, minutes: 0, seconds: 0 });
   const [mounted, setMounted] = useState(false);
 
@@ -58,15 +63,21 @@ export function SaleCountdown() {
     return <div className="h-24" />; // Placeholder to prevent hydration mismatch
   }
 
+  // Only show countdown if there are active sales
+  if (!hasActiveSale) return null;
+
   const isActive = timeLeft.days > 0 || timeLeft.hours > 0 || timeLeft.minutes > 0 || timeLeft.seconds > 0;
 
   if (!isActive) return null;
 
   return (
-    <div className="bg-gradient-to-r from-red-500 to-red-600 text-white py-4 px-6 rounded-lg shadow-lg mb-8 animate-pulse">
-      <div className="text-center">
-        <h3 className="text-lg sm:text-xl font-bold mb-2">🔥 AKCIJA SE ZAVRŠAVA!</h3>
-        <p className="text-sm sm:text-base mb-3">Popust od 5% važi još:</p>
+    <div className="relative bg-gradient-to-r from-blue-500 via-purple-500 to-orange-500 text-white py-4 px-6 rounded-lg shadow-lg mb-8 overflow-hidden">
+      <div className="absolute inset-0 bg-gradient-to-r from-transparent via-white/10 to-transparent animate-shimmer"></div>
+      <div className="relative text-center z-10">
+        <h3 className="text-xl sm:text-2xl font-bold mb-2">AKCIJA SE ZAVRŠAVA!</h3>
+        <p className="text-sm sm:text-base mb-3">
+          Popust od <span className="text-2xl sm:text-3xl font-extrabold text-yellow-300 mx-1">{maxSalePercentage}%</span> važi još:
+        </p>
         
         <div className="flex justify-center gap-2 sm:gap-4">
           <div className="bg-white/20 backdrop-blur rounded-lg px-2 sm:px-3 py-2 min-w-[60px] sm:min-w-[70px]">
@@ -89,10 +100,6 @@ export function SaleCountdown() {
             <div className="text-xs sm:text-sm opacity-90">sek</div>
           </div>
         </div>
-        
-        <p className="text-xs sm:text-sm mt-3 opacity-90">
-          Poruči sada i uštedi na Bambu Lab filamentima!
-        </p>
       </div>
     </div>
   );