nn4 = (document.layers);
ie4 = (document.all);
isWin = (navigator.appVersion.indexOf("Win") != -1);
isMac = (navigator.appVersion.indexOf("Mac") != -1);
isX11 = (navigator.appVersion.indexOf("X11") != -1);
var css = "def.css";
if ((nn4 || ie4) && isMac) {css = "mac.css";}
if ((nn4 || ie4) && isWin) {css = "win.css";}
if (nn4 && isX11) {css = "x11.css";}
document.write("<link rel=stylesheet type=text/css href=/css/" + css + ">");