if(navigator.userAgent.indexOf('Mac') != -1){
 if(navigator.appName.charAt(0)=="M"){
  document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="/sere_css/Mac_MSIE.css">')
 }else{
  document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="/sere_css/Mac_NN.css">')
 }
}

if(navigator.userAgent.indexOf('Win') != -1){
 if(navigator.appName.charAt(0)=="M"){
  document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="/sere_css/Win_MSIE.css">')
 }else{
  document.write('<LINK REL="stylesheet" TYPE="text/css" HREF="/sere_css/Win_NN.css">')
 }
}