I have looked at your site in Firefox 15.0.1, Chrome 13.0.782.112, Safari 5.0.3, Opera 12.02, Internet Explorer 8.0.6001.1872 and even Kindle Fire (via the Opera Mobile Emulator) on Windows XP.
All of these browsers show exactly the same layout with only a very minor difference in thickness to the borders in Opera. I don't think there is anything you can do about the way different graphics engines render borders.
Çok güzel olmuş! Hiç bir sorun yok.