css for only main page and for all other pages except main page

hello,
i have 2 custom css,
the first one, i want it ONLY for main page
the other one, i need it for all the other pages EXCEPT main page,
what do i make it done?

Name your homepage stylesheet index_home.css, and your main stylesheet stylesheet.css. Both of them go in /includes/templates/your_template/css/.
index_home.css only needs to include rules that are different from the rest of the site; stylesheet.css will be loaded first on all pages, and index_home will override it where necessary.

If you meant that your rest-of-site custom stylesheet only has some custom rules and not the entire site's rules, then name it stylesheet_custom.css, and it will be loaded after the stock stylesheet.css.