Nuxtjs Guideline: Environment — Use runtimeConfig for env vars. Description: Access environment variables safely. Do: runtimeConfig in nuxt.config. Don't: process.env directly. Good Example: runtimeConfig: { apiSecret: '', public: { apiBase: '' } }. Bad Example: process.env.API_SECRET in components. Severity: High. Docs: https://nuxt.com/docs/guide/going-further/runtime-config.