menu always repositioning

[Scightiee]

I was trying to make a menubar and a login page with using a \[code\]div\[/code\], but when I resize my browser (I am using Chrome) the \[code\]div\[/code\] changes and goes to the sides.Here is a demo: http://jsfiddle.net/xVenw/As you can see, it is not a line of menu. It adds another line when it is resized.