Something I totally overlooked is that it may be smart to replace the "<input />" buttons code by "<button></button>". It would probably offer better and more flexible cross browser compatible layout control.

HTML <button> tag
Definition and Usage

Defines a push button. Inside a button element you can put content, like text or images. This is the difference between this element and buttons created with the input element.
(source http://www.w3schools.com/tags/tag_button.asp)