Catcheverest Text Changes Size Randomly

Hello, Sometimes when I access by website www.t-pep.org from my twitter site (twitter.com/tpepoutreach) all of the text on the site increases in size. Similarly, sometimes if I double click on any of the navigation bar links all of the text gets real big until I refresh the page. Do you know of a reason for this? Is it something to do with the underlying theme code? If you can't initially see what I mean, try double clicking on each of the links in the navbar several times. The result is that all of the text on the page gets big. Is there something I can do to correct this? Thanks so much for all of your help on the forums by the way. They have been extremely helpful in getting my site up and running. Thanks, Brendan