How to change Pidgin colors in the IRC chat window nickname list

You can find examples on how to change backround and foreground colors for different Pidgin widgets here: http://developer.pidgin.im/wiki/Using%20Pidgin#HowdoIchangethefontPidginusesThebackgroundcolor

BUT

If you want to change the nickname list in IRC chat windows, you need to do this, which is not documented there:

style "blackbackground"
{
    base[NORMAL]   = "#000000"
}

widget "*pidgin_conv_userlist" style "blackbackground"

And here are the relevant bug report and code change.