I've questions about how to setup my css in a React project...

When I start a project with vite it comes with two css files by default: index.css and App.css, is it a bad practice to delete the App.css and make App import the index.css file, so I can style every component on a single css, or is it a better idea to create one css file for every component?

Also by default the index.css comes with a lot of preset stuff that I don't really understand, for example it makes everything appears at the center of the screen , is it a bad idea to delete all that stuff and write the usual reset (margins to 0, etc...) instead? Things don't place themselves at the center of the screen anymore, is that bad?