ok, i put the link in the header.php like this:
<link rel="stylesheet" href="bg_style.css" />
<style type="text/css">
<!--
.font1 { font-family: $VARS[font_face]; font-size: $VARS[tb_font_1]; color: $VARS[text_color] }
.font2 { font-family: $VARS[font_face]; font-size: $VARS[tb_font_2]; color: $VARS[text_color] }
.font3 { font-family: Arial, Helvetica, sans-serif; font-size: 7.5pt; color: $VARS[text_color]; font-weight: bold}
.select { font-family: $VARS[font_face]; font-size: 9pt}
.input { font-family: $VARS[font_face]; font-size: 9pt}
-->
</style>
and also tried putting the code right inside the style block:
<style type="text/css">
<!--
.font1 { font-family: $VARS[font_face]; font-size: $VARS[tb_font_1]; color: $VARS[text_color] }
.font2 { font-family: $VARS[font_face]; font-size: $VARS[tb_font_2]; color: $VARS[text_color] }
.font3 { font-family: Arial, Helvetica, sans-serif; font-size: 7.5pt; color: $VARS[text_color]; font-weight: bold}
.select { font-family: $VARS[font_face]; font-size: 9pt}
.input { font-family: $VARS[font_face]; font-size: 9pt}
scrollbar-face-color: #767676;
scrollbar-highlight-color: #CCCCCC;
scrollbar-shadow-color: #333333;
scrollbar-3dlight-color: #999999;
scrollbar-arrow-color: #999999;
scrollbar-track-color: #111111;
scrollbar-darkshadow-color: #333333;
-->
</style>
none of them worked!