Und was wäre, wenn der Code sondern so aussehen würde:
<div id="2cols">
<div class="left">Page 1</div>
<div class="left">Page 2</div>
<div class="left">Page 3</div>
<div class="left">Page 4</div>
<div class="right">Page 5</div>
<div class="right">Page 6</div>
</div>
also class anstatt id