diff --git a/README.md b/README.md
index 92c9319..c6c6f34 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,40 @@ a simple webpage which will connect to a remote ollama instance and allowes you
 
 ## configuration
 
-all configuration is done in the file default.php
+All application configuration is now stored in `default.php`.
+
+If you previously used `config.php`, its settings have already been merged into `default.php`.
+
+### key settings
+
+- `USER_CONFIG_DIR`: directory where user data and chat history are saved.
+- `OLLAMA_URL`: URL of your remote Ollama instance.
+- `GUEST_USER_ENABLED`: enable guest access when set to `true`.
+- `GUEST_USERNAME`: guest account username (default is `guest`).
+- `DEFAULT_MODEL`: default Ollama model used for new chats.
+- `MAIL_FROM` / `MAIL_FROM_NAME`: email sender details for password reset messages.
+- `APP_BASE_URL`: the public app URL used to generate links.
+- `APP_SECRET`: secret key used for authentication token signing and security.
+
+> Note: change `APP_SECRET` from the default before deploying to production. Use a long, random value and keep it private.
+
+### example settings
+
+```php
+<?php
+
+define('USER_CONFIG_DIR', '/var/lib/KaI/users');
+// URL of the Ollama API server, e.g. http://127.0.0.1:11434
+define('OLLAMA_URL', 'http://127.0.0.1:11434');
+
+define('GUEST_USER_ENABLED', true);
+define('GUEST_USERNAME', 'guest');
+define('DEFAULT_MODEL', 'llama3.2:latest');
+
+define('MAIL_FROM', getenv('MAIL_FROM') ?: 'noreply@kai.local');
+define('MAIL_FROM_NAME', getenv('MAIL_FROM_NAME') ?: 'KaI');
+define('APP_BASE_URL', getenv('APP_BASE_URL') ?: 'http://127.0.0.1/KaI-OllamaChat');
+define('APP_SECRET', getenv('APP_SECRET') ?: 'change-this-secret');
+```
 
 
diff --git a/config.php b/config.php
deleted file mode 100644
index 16a6cde..0000000
--- a/config.php
+++ /dev/null
@@ -1,8 +0,0 @@
-<?php
-
-define('USER_CONFIG_DIR', '/var/lib/KaI/users');
-define('OLLAMA_URL', 'http://127.0.0.1:11434');
-define('GUEST_USER_ENABLED', true);
-define('GUEST_USERNAME', 'guest');
-define('DEFAULT_MODEL', 'llama3.2:latest');
-
diff --git a/default.php b/default.php
index 74943cc..0de2b0f 100644
--- a/default.php
+++ b/default.php
@@ -1,6 +1,10 @@
 <?php
 
-require_once __DIR__ . '/config.php';
+define('USER_CONFIG_DIR', '/var/lib/KaI/users');
+define('OLLAMA_URL', 'http://127.0.0.1:11434');
+define('GUEST_USER_ENABLED', true);
+define('GUEST_USERNAME', 'guest');
+define('DEFAULT_MODEL', 'llama3.2:latest');
 
 define('MAIL_FROM', getenv('MAIL_FROM') ?: 'noreply@kai.local');
 define('MAIL_FROM_NAME', getenv('MAIL_FROM_NAME') ?: 'KaI');
diff --git a/index.php b/index.php
index a415e63..d784859 100644
--- a/index.php
+++ b/index.php
@@ -44,7 +44,7 @@ $isGuestSession = isGuestSession();
                 <?php if (($authUser['role'] ?? 'user') === 'admin'): ?>
                     <a href="useradmin.php" style="color:#89b4fa; text-decoration:none;">User Admin</a>
                 <?php endif; ?>
-                <?php if (isGuestModeEnabled()): ?>
+                <?php if (isGuestModeEnabled() && isGuestSession()): ?>
                     <a href="login.php" style="color:#89b4fa; text-decoration:none;">Login</a>
                 <?php endif; ?>
                 <a href="logout.php" style="color:#f38ba8; text-decoration:none;">Logout</a>