Remove all sidebars in child theme?

Hey all,

I know very little code, but have learned it’s best to set up a child theme to keep changes sterilized from updates. I’ve read about how to delete sidebar coding from the (parent) index.php but don’t know how to add code to my child stylesheet to intercept these sidebar commands.

How can I remove the Sidebar Home, Sidebar Main, and Sidebar Posts from the theme using my child style.css?

Thanks so much for any help!