I would like to add this piece of code to page.tpl.php so that I can track when people are logged in/guests etc on the CSS level.

<body class="<?php echo $body_classes; ?>"

The existing default code is this.

<?php print phptemplate_body_class($left, $right); ?>>

And when I try to add the above code in, I can get it to work but it slams all my content to the bottom of the page below the left and right blocks (instead of content being in the middle between them)

Any suggestions? Thanks!