Shortcodes Ultimate tab color reverse

I am designing the website potenzadevelopment.com/superior. On one of my pages I have small group of 2 tabs. This is located at http://potenzadevelopment.com/superior/work-with-us-2/?preview=true

Anyway the tabs are made in Shortcodes Ultimate, and for some ungodly reason the client wants to switch the color of the tab set, in other words for it to be grey when you are on that tab, and white when you are not. I know ridiculous, however I still have to execute it somehow. How can this be accomplished?

https://ww.wp.xz.cn/plugins/shortcodes-ultimate/