Ask HN: What is the wiki software used at golden.com?

I have been searching for a good looking wiki software for some months. It seems like golden.com fits the bill for me. (Eg: https://golden.com/wiki/Dashblock). I like the fonts and buttons etc. I am using mediawiki for my site but I have not seen good skins for it.

Any one here where or which wiki software/UI themes are being used by golden.com?

Thanks!