The goal of a reset stylesheet is to reduce browser inconsistencies in things like default line heights, margins and font sizes of headings, and so on.
The reset styles given here are intentionally very generic. There isn’t any default color or background set for the body element, for example. I don’t particularly recommend that you just use this in its unaltered state in your own projects. It should be tweaked, edited, extended, and otherwise tuned to match your specific reset baseline. Fill in your preferred colors for the page, links, and so on.