List of variables to use for CSS

[ys.chee]

I am looking to apply CSS into a page, so I would like a list of objects in which I am able to apply CSS to. Is there a way to bring up a list of available objects in a page to apply CSS to, in terms of legal variables? For example, I want to see what is the equivalent of first-child/nth child.

Also, is there a list of attributes that are legal for each type of object? Recently I noticed that font-(attribute) attributes don't work.

Thanks for reading.