diff --git a/src/pages/projects.astro b/src/pages/projects.astro
index 1c79a01..1e02338 100644
--- a/src/pages/projects.astro
+++ b/src/pages/projects.astro
@@ -84,7 +84,7 @@ const filterOptions = [
     const filterButtons = Array.from(projectsRoot.querySelectorAll("[data-filter]"));
     const projectCards = Array.from(projectsRoot.querySelectorAll("[data-project-card]"));
 
-    const applyFilter = (activeFilter) => {
+    const applyFilter = (activeFilter: string | null) => {
       projectCards.forEach((card) => {
         const projectType = card.getAttribute("data-type");
         const shouldShow = activeFilter === "all" || projectType === activeFilter;