Regular <link> stylesheets and global CSS files are still supported.
In production, all CSS Module files will be automatically concatenated into many minified and code-split .css files.
These .css files represent hot execution paths in your application, ensuring the minimal amount of CSS is loaded for your application to paint.
Global Styles
Global styles can be imported into any layout, page, or component inside the app directory.
Good to know: This is different from the pages directory, where you can only import global styles inside the _app.js file.
For example, consider a stylesheet named app/global.css: body {
  padding: 20px 20px 60px;
  max-width: 680px;
  margin: 0 auto;
}Inside the root layout (app/layout.js), import the global.css stylesheet to apply the styles to every route in your application:app/layout.tsx // These styles apply to every route in the application