Nuxtjs Guideline: Environment — Use NUXT_ prefix for env override. Description: Override config with environment variables. Do: NUXT_API_SECRET NUXT_PUBLIC_API_BASE. Don't: Custom env var names. Good Example: NUXT_PUBLIC_API_BASE=https://api.example.com. Bad Example: API_BASE=https://api.example.com. Severity: High. Docs: https://nuxt.com/docs/guide/going-further/runtime-config.