:root { --bg:#f6f9fa; --text:#0f172a; --muted:#475569; --accent:#0f766e; }
  @media (prefers-color-scheme: dark) { :root { --bg:#0b1120; --text:#e2e8f0; --muted:#94a3b8; --accent:#2dd4bf; } }
  html,body { margin:0; height:100%; }
  body { background:var(--bg); color:var(--text); font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
         display:grid; place-items:center; padding:24px; box-sizing:border-box; text-align:center; }
  h1 { font-size:clamp(28px,5vw,44px); margin:0 0 10px; letter-spacing:-.02em; }
  h1 span { color:var(--accent); }
  p { color:var(--muted); margin:6px 0; }