Adding a Border to the Top Menu Dropdowns

Hola again

One of the skins we looked at before settling on the iStore theme has a really nice looking top menu with a coloured border round the edge. I've spent the last 3 hours trying to replicate this with little success, my attempt looked utterly s**t. We would like the layout to look the same with the highlighted category headers etc, just in different colours. Can anyone advise me the best way to go about this please?

Here is a link to the demo of the theme: http://cscarttemplat…rs-v3/index.php

Here is the theme we are using: http://cscarttemplat…apple/index.php

Thanks in advance