if (navigator.platform.indexOf("Mac") != -1) {
  document.open();
  document.writeln("<link id='style' rel='stylesheet' type='text/css' href='../css/list_mac.css'>");
  document.close();
}else{ 
  document.open();
  document.writeln("<link id='style' rel='stylesheet' type='text/css' href='../css/list.css'>");
  document.close();
}