[LifesGreatestGift]

<script type="text/javascript">
if (screen.width <= 1024) window.location.replace("http://www.urltoforum.com/styleforsmallerscreens")
</script>

Pretty sure that if the decided they wanted to use the regular style though, they would be continuously redirected based on screen resolution because the script would just run again on the main style and see they have a small screen and redirect them back to the 'mobile' style.