On the presentation page in Safari, the text inside columns is way too up. Depending on the amount of the text, the titles of the columns may not show up at all. I just checked the demo page of Nirvana, and noticed the same problem.
Chrome or Firefox show columns properly. Did not check it in IE as I’m limited to Mac at the moment.
Sounds like your browser is handling CSS incorrectly (as if it were an older obsolete version). Can you link to your site so we can check it out ourselves?