Next.js has built-in support for CSS Modules allowing you to write scoped CSS by automatically creating a unique class name. CSS Module files can be imported anywhere in your application and you don't have to worry about collisions.
Deploy the example using Vercel or preview live with StackBlitz
Execute create-next-app
with npm, Yarn, or pnpm to bootstrap the example:
npx create-next-app --example basic-css basic-css-app
yarn create next-app --example basic-css basic-css-app
pnpm create next-app --example basic-css basic-css-app
Deploy it to the cloud with Vercel (Documentation).