Scoped styling settings define the global styles that are to be applied to the page. Both the styles and the links to CSS files will be added to the page as late as possible in order to increase the specificity. However, it might be possible that SharePoint or other apps inject their own CSS and override your styles. In this situation you will have to rewrite the affected selectors in order to increase their specifcity.
The global CSS that will be applied to the page.
The URL of the CSS files to be injected in the page. Configuring a URL here wil result in a tag in the page that will load the CSS file.