var apOS = navigator.userAgent ;

if ( apOS.indexOf("Win") >= 0 ) {
    userOS = "Win" ;
}
if ( apOS.indexOf("Mac") >= 0 ) {
    userOS = "Mac" ;
}

if ( userOS == "Win" ) {
    document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="http://www.maedamokuzai.com/css/win.css">') ;
    document.close( ) ;
}
else if ( userOS = "Mac" ) {
    document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="http://www.maedamokuzai.com/css/mac.css">') ;
    document.close( ) ;
}