var ostr = navigator.appVersion.toUpperCase();
var Win = ostr.indexOf('WIN') >= 0;	// Flag of Windows
var Mac = ostr.indexOf('MAC') >= 0;	// Flag of Macintosh

	if(Mac){
		document.write('<meta http-equiv="content-Style-Type" content="text/css"><LINK rel="stylesheet" href="/web_ent/css/txt_mac.css" type="text/css">');
	}
	if(Win){
		document.write('<meta http-equiv="content-Style-Type" content="text/css"><LINK rel="stylesheet" href="/web_ent/css/txt_win.css" type="text/css">');
	}