Nextjs Guideline: Fonts — Use next/font for fonts. Description: Self-hosted fonts with zero layout shift. Do: next/font/google or next/font/local. Don't: External font links. Good Example: import { Inter } from 'next/font/google'. Bad Example: <link href="fonts.googleapis.com"/>. Severity: Medium. Docs: https://nextjs.org/docs/app/building-your-application/optimizing/fonts.