Component-level #CSS in in Next.js is an optional feature. You can create a file called button.module.css, import this in you button.js file. In production, all CSS Module files will be automatically concatenated into many minified and code-split .css files.
import styles from './Button.module.css'
export function Button() {
return (
<button
type="button"
// Note how the "error" class is accessed as a property on the imported
// `styles` object.
className={styles.error}
>
Destroy
</button>
)
}