Popup Pro plugin multilingual, and change in background colour of popup

Hi

We have custom coded the popup for our website.
But there is a problem with the background colour.

1. How to achieve white background?
the brightest colour we were able to achieve is a light grey you will see on the image attached.

2.The popup Pro plugin is compatible with WPML plugin. Our site is in two languages at the moment, Polish and English. The popup form needs to be in English and Polish.
the thing is, that the Polish form should be connected to the Polish newsletter list, and the English form should be connected to the English newsletter.
How to achieve this?
Our site is built on Wordpress and Salient skin.

Thank you, Martyna Bizdra