Jquery DatePicker - CSS theme for it messes up the page's CSS -- gap at the bottom

If you take a look at this page in FF or IE ---

http://www.theseagatehotel.com/www.theseagatehotel.com/test.html

-- and scroll down to the bottom of the page -- you'll see that there's a 20px gap at the bottom.

That gap isn't supposed to be there.  The design should go all the way down to the bottom.

See this page for an example of how the page should display:

http://www.theseagatehotel.com/www.theseagatehotel.com/index.html

It seems that adding the CSS file for the datepicker/calendar  -- jquery-ui-1.7.2.custom.css -- namely the "cupertino" theme, .. is the culprit behind the problem.

The odd thing is -- when you click in one of the text input fields (or click on one of the calendar icons) .. the gap at the bottom of the page instantly goes away.

How can I eliminate that gap at the bottom of the page?  Can the CSS file be tweaked somehow?  Or is there some kind of javascript function that I can call onload that will eliminate the gap?

Thanks,
- Yvan