"puff" animation is not as expected

"puff" animation is not as expected

I would want to make this effect that can be run selecting "puff" in the JqUI demos page
http://jqueryui.com/effect/#default

I placed the the necessary code in my website
http://americanhorizon.altervista.org/portfolio/portfolio.php
.. try to click the sections on top, the main contet should "puff" while actually they move on the left. Where i wrong?