Border layout sub-menu primary navigation

Hi Tom,

My first time creating a full website, everything new, tons of stuff to learn!
With a slight ICT background I wanted something highly customizable and instantly knew your theme was the way to go.... it rocks!

That said, I've come a long way creating my first website (not online yet), also by reading through this forum...

I made a primary menu and styled the borders with CSS to make 'm look somewhat like buttons.

.main-navigation {
border-top: 2px solid #eee0df;
border-bottom: 2px solid #eee0df;
}

.main-navigation ul li {
border-right: 2px solid #eee0df;
}

.main-navigation ul li:first-of-type {
border-left: 2px solid #eee0df;
}

My problem is these lines also show up in the dropdown sub-menu. I dont want them there or be able to customize thoser borders as well!?

Could ya help me out, im kinda stuck :)?

Regards,
Rob