fix: Center the similar products grid on product pages

src/components/product/ProductDetail.tsx

@@ -414,7 +414,7 @@ export default function ProductDetail({ product, relatedProducts, locale = "SR"
                 {locale === "EN" ? "Similar Products" : "Slični proizvodi"}
               </h2>
             </div>
-            <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-6 lg:gap-8">
+            <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-6 lg:gap-8 justify-center">
               {relatedProducts.filter(p => p && p.id).slice(0, 4).map((relatedProduct, index) => (
                 <ProductCard 
                   key={relatedProduct.id}