Sparky Pro layout.css

Please forgive my inexperience...

1) is this the file (template_css.css) to define how Modules look? I want to make all my modules have the same border, background... If so, what section?
2) If I modify any code in this document, will it override some of the settings in the Sparky template settings?

Thanks for any help!

That is main template css file , it is loaded on every page . So it is good place for such modifications. Put your cod at end of that file