What happens here (css) is: you have a badly coded template, it is missing one important element: the base href

Why such an important element is missing? I guess only your coder can tell.

Anyhow, this line of code needed to be added to your html_header.php right above the <body> tag

PHP Code:
<base href="<?php echo (($request_type == 'SSL') ? HTTPS_SERVER . DIR_WS_HTTPS_CATALOG : HTTP_SERVER . DIR_WS_CATALOG ); ?>" />
I guess you have to fix that one first before trying anything else.