Widgets and Themes – Background Changing

Hello all,

I’m currently in need of some help concerning widgets and would appreciate any assistance.

My website is at : http://demos.usefuldesign.co.uk/

If you look at the sidebar you’ll see that the color of the bit changes depending on what it is (i.e search – dark blue, archives – light blue etc)

I’d like to repeat this with a widgetized sidebar and have no idea of how to do this.

Each “box” as I call it has it’s own DIV tag but the content class remains the same :

Archives – box1(css tag)
Categories – box2(css tag)
Search – box3(css tag)

and then it repeats itself.

Any ideas of how this could be done ?

Many Thanks,
Stephen