var Win=(navigator.userAgent.indexOf("Win")!=-1);
var Mac=(navigator.userAgent.indexOf("Mac")!=-1);
var Explorer=(navigator.appName.indexOf("Explorer")!=-1);
var Netscape=(navigator.appName.indexOf("Netscape")!=-1);
var opera=(navigator.userAgent.indexOf("Opera")!=-1);
var safari=(navigator.userAgent.indexOf("Safari")!=-1);
var firefox=(navigator.userAgent.indexOf("Firefox")!=-1);
var Version=navigator.appVersion.charAt(0);
if
(opera)
{document.write("<LINK rel='stylesheet' href='"+level+"css/pixel.css' type='text/css'>");}
else if
(safari)
{document.write("<LINK rel='stylesheet' href='"+level+"css/safari.css' type='text/css'>");}
else if
(firefox)
{document.write("<LINK rel='stylesheet' href='"+level+"css/firefox.css' type='text/css'>");}
else if
(Win && Explorer && Version=="4")
{document.write("<LINK rel='stylesheet' href='"+level+"css/key_tra.css' type='text/css'>");}
else if
(Win && Netscape && Version=="4")
{document.write("<LINK rel='stylesheet' href='"+level+"css/win_nn4.css' type='text/css'>");}
else if
(Explorer && Mac && Version=="4") 
{document.write("<LINK rel='stylesheet' href='"+level+"css/mac_ie.css' type='text/css'>");}
else if
(Mac && Netscape && Version=="5")
{document.write("<LINK rel='stylesheet' href='"+level+"css/mac_nn6.css' type='text/css'>");}
else if
(Mac && Netscape && Version=="4")
{document.write("<LINK rel='stylesheet' href='"+level+"css/mac_nn4.css' type='text/css'>");}
else
{document.write("<LINK rel='stylesheet' href='"+level+"css/pixel.css' type='text/css'>");}