:root{background:#f6f7f9;color:#1a1a1a;font-family:system-ui,sans-serif}.layout{min-height:100vh}.header{background:#fff;border-bottom:1px solid #e5e7eb;display:flex;gap:1.25rem;padding:1rem 1.5rem}.header a{color:#2563eb;text-decoration:none}.header a:hover{text-decoration:underline}.header a.ext{color:#64748b;font-size:.9rem;margin-left:auto}.main{max-width:40rem;padding:1.5rem}