If you're able to rename your CSS file "layout.php", there's no need for all of these workarounds:
Your layout.php file would look like:
body{ margin:0px; font:9px/11px "Tahoma", Arial, Helvetica, sans-serif; color:#010000;
background:#f3f6e1 url(images/body_bg_1.gif) repeat-x 0 0}
Your HTML files would look like:
This question is very similar: Include: css with php file extension?
