// set Variable
var agent = navigator.userAgent;
  if(navigator.appVersion.indexOf('Mac') > 1){
   document.write('<link rel="stylesheet" type="text/css" href="css/mac.css" media="screen">');
   document.write('<BASEFONT SIZE="3">');
  }else if(agent.indexOf('Win') >= 0 && navigator.appVersion.indexOf('M')!=-1){
   document.write('<link rel="stylesheet" type="text/css" href="css/win.css" media="screen">');
   document.write('<BASEFONT SIZE="2">');
  }else if(agent.indexOf('Win') >= 0 && navigator.appName.charAt(0) == "N" && navigator.appVersion.charAt(0) >= 4){
   document.write('<link rel="stylesheet" type="text/css" href="css/win.css" media="screen">');
   document.write('<BASEFONT SIZE="3">');
  }else{
   document.write('<link rel="stylesheet" type="text/css" href="css/mac.css" media="screen">');
  }

// for debug
/*
alert(flag);
*/