Problem with theme and zoom of browsers

[Enrico2]

Hi,

I need help because I'm already starting to come crazy. I'm practicing to modify themes and learning to design step by step. I started by changing the images of the blocks (they are identical to the original but different color) and change colors in the CSS.

The page will display correctly in all browsers when the zoom is 100% or more, but when I zoom out, is when i have a problem, each browser does something different. I have not touched any width or height in the CSS.

I understand that the zoom out is not very important, but I would not lose composition of theme. Comment that in the original template Prestasho 1.4 also is the same. If you have any idea ... please tell me

Thanks in advance, see the images below. Sorry for my bad English ;P

Internet Explorer 9:
http://i51.tinypic.com/2dt812g.jpg

Chrome 10:

http://i54.tinypic.com/2vc7zfo.jpg

Safari:

http://i55.tinypic.com/2r5dz5g.jpg

Firefox 4:

http://i56.tinypic.com/24papfm.jpg