if (navigator.userAgent.indexOf('Mac') != -1) {
document.write('<link rel="stylesheet" type="text/css" media="all" href="/common/css/mac_font.css">');
}

if (navigator.userAgent.indexOf('Vista') != -1) {
document.write('<link rel="stylesheet" type="text/css" media="all" href="/common/css/vista_font.css">');
}