Coding for Different Index and Secondary Pages

Hello everyone,

I am familiar with CSS coding, but not so sure how to organize my files/how many style sheets to have.

I am creating a website using ‘A Thematic Child Theme’ as my base (because I read it’s very good for coding from scratch) but I want an index page that looks different from my secondary pages.

What I am unsure about is this: Does my CSS for the index page and my CSS for my secondary pages go on the same style sheet? If so, how do I call a chunk of code for the index only, and use the other part of the code for the rest of the sight?

I’ve also read that’s it’s best to minimize the amount of style sheets you have, so I am thinking everything is in one?

Thanks so much for your time.