diff --git a/js/filter.js b/js/filter.js
index 32ec154..f5835e8 100644
--- a/js/filter.js
+++ b/js/filter.js
@@ -6,7 +6,7 @@ function initFilter() {
     if (!filterSelect || !listContainer) return;
 
     filterSelect.addEventListener('change', function() {
-        const selectedCategory = this.value;
+        const selectedCategory = this.value.toLowerCase();
         const cards = listContainer.querySelectorAll('.s-res-item');
 
         cards.forEach(card => {