if ( navigator.appVersion.indexOf('Mac') != -1 ) {
  if ( navigator.appName.indexOf('Microsoft') != -1 ) {
    document.write( '<link rel="stylesheet" href="' + _css_rel_path + 'css/macIE.css" type="text/css">' );
  } else {
    document.write( '<link rel="stylesheet" href="' + _css_rel_path + 'css/macNN.css" type="text/css">' );
  }
} else {
  if ( navigator.appName.indexOf('Microsoft') != -1 ) {
    document.write( '<link rel="stylesheet" href="' + _css_rel_path + 'css/winIE.css" type="text/css">' );
  } else {
    document.write( '<link rel="stylesheet" href="' + _css_rel_path + 'css/winNN.css" type="text/css">' );
  }
}