How do I modify the color scheme of the q&a plugin to fit site colors?

Okay can you please be specific
Change the css instead of the php file, right?
where?
where are the element tags to reference?
give an example of changing the q&a plugin for a black website.
Please be specific. This plugin does not have documentation that I can find.
Wouldn't it be simple to provide these settings in the settings area of the plugin?
At least give some instruction on doing it in css, wherever that is. I'm not a coder. I didnt think I had to be to use wordpress and plugins. Currently the qa plugin looks nothing like the demo. I have a black site