pure CSS pop-up menu - submenu further apart from parent

[websj06]

hello everyone:

a) I am trying to design a pop-up menu by using pure css without any script.
my problem is that sub-menu displayed little further apart from it's parent menu.

http://www.cuj06.com/css_menu/css_pup_upmenu.html

Where original sample showed that sub-menu just right next to it's parent. I made some modification
to adjust left attribute in style -->ul li ul.

Code:

ul li ul {
    list-style: none;
    position: absolute;
    left: 100px;
    top: 0;
    display: none;
    width: 125px;
    border-left: 1px solid #FFF;
}

In IE 7 it displayed ok, but in Firefox browser Gallery portion has a vertical bar displayed. I want it to look
identical to rest of three menu items (home, about, product). Could someone look at my code and me some suggestion how to resolve this issue. Thanks for your help!

b) I also want to create a pop-up menu(vertical and horizontal) by using javascript. If you know some good toturials give step by step
instructions please share with me.

Jeff
4-8-07