Use external static files with your component
This approach is useful if you are using a global design system or design approach, and want to manage your global styling centrally. It is particularly useful when your design system is made up of many components. There is less benefit in trying to make your components self-contained if they will be part of an overarching design approach.
Set up your preview files to reference your global styles and scripts which can be served from your CMS or other delivery platform.