include css file (templates)

functions/page_header.php

@@ -57,6 +57,8 @@ function displayHtmlHeader( $title = 'SquirrelMail', $xtra = '', $do_hook = true
              $base_uri . 'themes/css/'.$custom_css.'">';
     }
 
+    echo '<link rel="stylesheet" type="text/css" href="'. SM_PATH .'templates/default/squirrelmail.css">';
+
     if ($squirrelmail_language == 'ja_JP') {
         /*
          * force correct detection of charset, when browser does not follow