It looks like there's some padding on the inner UL from the user agent stylesheet
I added an extra rule to remove it, and it seems to work:
li ul
{
padding: 0
}
The same thing seems to also happen to the parent UL, which shows up on the "E" element To fix that one, just remove the padding from the parent UL as well.
You could also consider using a browser reset, which may automatically reset padding, at least so its consistent between browsers.