diff --git a/index.html b/index.html
index e233e9f..ae04798 100644
--- a/index.html
+++ b/index.html
@@ -285,14 +285,22 @@
   <script>
     function checkSession() {
       const sessionid = getCookie('sessionid');
+      console.log('checkSession: sessionid =', sessionid);
       if (sessionid) {
-        document.getElementById('intro-section').classList.add('hidden');
-        document.getElementById('news-col').classList.add('hidden');
-        document.getElementById('login-panel').classList.add('hidden');
-        document.getElementById('notebook-panel').classList.remove('hidden');
+        const intro = document.getElementById('intro-section');
+        const news = document.getElementById('news-col');
+        const login = document.getElementById('login-panel');
+        const notebook = document.getElementById('notebook-panel');
+        console.log('checkSession elements:', { intro, news, login, notebook });
+        if (intro) intro.classList.add('hidden');
+        if (news) news.classList.add('hidden');
+        if (login) login.classList.add('hidden');
+        if (notebook) notebook.classList.remove('hidden');
       } else {
-        document.getElementById('notebook-panel').classList.add('hidden');
-        document.getElementById('login-panel').classList.remove('hidden');
+        const notebook = document.getElementById('notebook-panel');
+        const login = document.getElementById('login-panel');
+        if (notebook) notebook.classList.add('hidden');
+        if (login) login.classList.remove('hidden');
       }
     }
 
@@ -438,7 +446,9 @@
     }
 
 
-    checkSession();
+    document.addEventListener('DOMContentLoaded', () => {
+      checkSession();
+    });
   </script>
 </body>
 </html>
\ No newline at end of file