Drop down Menu problem- the lower part becomes transparent

[plymouthhypno]

My sitehttp://www.plymouth-hypnotherapist.co.uk has drop-down menus. These worked fine before I increased the font size of entire site to make it more readable. Now, the lower items on the menus display incorrectly- as if the menu has become transparent and the words are supermiposed on the underlying page, making them hard to read. The problem affects specifically the "common problems" menu.

Where would I find the code that controls the transparency/opacity of the menus?

[Dr.CSS]

The drop menu background is 2 images, the top one is only 400px tall so it doesn't cover all the links you have...

Use an image manipulation software to make it taller...

http://plymouth-hypnotherapist.co.uk/up ... /ultop.png