diff --git a/internal/server/routes.go b/internal/server/routes.go
index 2cd1530..2c15e75 100644
--- a/internal/server/routes.go
+++ b/internal/server/routes.go
@@ -73,10 +73,17 @@ func (s *Server) SetupRoutes() {
 		fileServer := http.FileServer(http.FS(distFS))
 
 		s.router.Get("/*", func(w http.ResponseWriter, r *http.Request) {
+			readFS, ok := distFS.(fs.ReadFileFS)
+			if !ok {
+				http.Error(w, "internal error", http.StatusInternalServerError)
+
+				return
+			}
+
 			// Try to serve the file; if not found, serve index.html for SPA routing
-			f, err := distFS.(fs.ReadFileFS).ReadFile(r.URL.Path[1:])
+			f, err := readFS.ReadFile(r.URL.Path[1:])
 			if err != nil || len(f) == 0 {
-				indexHTML, _ := distFS.(fs.ReadFileFS).ReadFile("index.html")
+				indexHTML, _ := readFS.ReadFile("index.html")
 
 				w.Header().Set("Content-Type", "text/html; charset=utf-8")
 				w.WriteHeader(http.StatusOK)