WebPlus X4: Drop down box from navigation bar

I'm still very much a newbie with using Webplus X4 but managing to update my website as and when. One thing I would like to change if possible but can't work out how (or what I should be looking up in the manual!) is how to change the drop down boxes from the level 1 navigation bar which shows child pages (am I making sense?) from transparent to opaque, and possibly from grey to something more attractive? Currently they are hard to read as the text on the Home page shows through.

If you look at my website www.blueboxstudio.co.uk and hover over 'home' you will get a drop down with 4 options so will be able to see what I am trying to say/ask?

Thanks for your help!