fix(nav): improve redirection logic

app/exam/exam-screen/page.tsx

@@ -57,7 +57,8 @@ export default function ExamPage() {
 
   if (isSubmitting) {
     return (
-      <div className="min-h-screen bg-gray-50 flex items-center justify-center">
+      <div className="min-h-screen bg-gray-50 flex flex-col items-center justify-center">
+        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-900 mb-4"></div>
         <p className="text-lg font-medium text-gray-900">Submitting exam...</p>
       </div>
     );
@@ -118,14 +119,7 @@ export default function ExamPage() {
               disabled={isSubmitting}
               className="flex-1 bg-blue-900 text-white p-6 font-bold text-lg disabled:opacity-50 disabled:cursor-not-allowed hover:bg-blue-800 transition-colors flex justify-center items-center gap-2"
             >
-              {isSubmitting ? (
-                <>
-                  <span className="animate-spin rounded-full h-5 w-5 border-b-2 border-white"></span>
-                  Submitting...
-                </>
-              ) : (
-                "Submit"
-              )}
+              Submit
             </button>
           </div>
         </div>

app/exam/results/page.tsx

@@ -11,10 +11,16 @@ import { getResultViews } from "@/lib/gallery-views";
 export default function ResultsPage() {
   const router = useRouter();
   const { result, clearResult, setStatus, status } = useExamStore();
+
+  function handleBackToHome() {
+    clearResult();
+    router.replace("/categories");
+  }
+
   useEffect(() => {
     const handlePopState = () => {
       if (status !== "finished") {
-        router.replace(`/categories`);
+        handleBackToHome();
       }
     };
 
@@ -32,11 +38,6 @@ export default function ResultsPage() {
     );
   }
 
-  const handleBackToHome = () => {
-    clearResult();
-    router.replace("/categories");
-  };
-
   const views = getResultViews(result);
 
   return (