A newbie question

[html20009876]

I am trying html menu, following is part of code copied from google.

#myMenu ul 
{
    position: absolute;
    display: none;
    z-index: 999;
}

#myMenu ul li a 
{
    width: 80px;
}

I changed it to this:

#myMenu ul 
{
    position: absolute;
    width: 80px;
    display: none;
    z-index: 999;
}

#myMenu li a 
{
    width: 80px;
}

"width: 80px" was simply moved up.
However, things are changed, the modified line in ul is not working again.

Could you explain reason or differences of above code?
I am very very ... confused with css format of this kind.

Thanks.

[holyhttp]

Assuming #myMenu ul is the CSS selector for a sub-menu:
#myMenu ul li a refers to a hyperlink in a sub-menu
#myMenu li a on the other hand just refers to any hyperlink in your overall menu whether its a top level menu link or a sub-menu link.

So use #myMenu li a for the topmost links
and specify below
#myMenu ul li a for sublinks