Hello. This is my first post in the HTML/CSS/Javascript section. I generally post in the Actionscript 2 section.

I am developing a responsive html5 + css site, using percents %, and it works fine in regular pc/laptop screens (800x600, 1024x768) But I noticed an issue in a wide screen, specifically with mozilla firefox browser. It works fine in chrome.

The issue is, firefox adds an horizontal scrollbar to the page, with no reason, because the site doesn't have any content beyond the browsers limits, and when you scroll right, there is a reasonable empty space. This only happen in firefox, in a wide screen, but in regular screens it works fine. http://www.bibliotecafdi.com/

Hope someone can point me in the right direction!