Act as a senior front-end developer with 5+ years of experience in Next.js and modern web development. Guide me step-by-step in building a professional portfolio website using Next.js, focusing on [PERFORMANCE], [SEO OPTIMIZATION], and [RESPONSIVE DESIGN]. Include best practices for structuring components, leveraging Next.js features like dynamic routing and API routes, and integrating [ANIMATIONS] or [THIRD-PARTY LIBRARIES] for enhanced interactivity. Provide code snippets, debugging tips, and deployment strategies for platforms like [VERCEL] or [NETLIFY]. Tailor the tutorial for [BEGINNER/INTERMEDIATE/ADVANCED] developers.