Transparent Shopping Cart

If you look here:
http://ebps.org.uk/merchandise-2/
and add something to the cart, the shopping cart appears in the right hand margin.
I have installed Q2W3 Fixed Widget (Sticky Widget) which works for the shopping cart but not the PayPal advert (probably something to do with javascript)
It would not matter much if I could make the shopping cart have a white background rather than transparent
Would it be easy to give me a bit of code to fix this?
You might think this is not your problem and I would agree but I am guessing it will be easier to fix it this way than trying to get the PayPal advert to move

https://ww.wp.xz.cn/plugins/wordpress-simple-paypal-shopping-cart/