if (window.innerWidth) {
  breite = window.innerWidth;
  hoehe = window.innerHeight;
} else {
  breite = document.documentElement.clientWidth;
  hoehe = document.documentElement.clientHeight;
}


var stylesheet = 'size_800.css';
if (breite > 1000) { 
  stylesheet = 'size_1024.css';
}

if (stylesheet != '') {
  document.writeln('<style type="text/css"><!-- @import url(layout/' + stylesheet + '); --></style>');
}