if(navigator.userAgent.indexOf("Mac") == -1)
{
if(navigator.userAgent.indexOf("Win") != -1)
   {
   document.write('<LINK HREF="http://www.unternehmenskommunikation.ch/kistler/css/basic_css" TYPE="text/css" REL="stylesheet">');
   }
else if(navigator.userAgent.indexOf("X11") != -1)
   {
   document.write('<LINK HREF="http://www.unternehmenskommunikation.ch/kistler/css/basic_css" TYPE="text/css" REL="stylesheet">');
   }
}