:root{--bg:#f6f7f9;--surface:#fff;--ink:#1c2330;--muted:#6b7280;--line:#e5e7eb;--brand:#2563eb}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--ink)}.center{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:16px}.card{width:100%;max-width:360px;background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:24px;box-shadow:0 1px 3px #0000000f}.card h1{font-size:18px;margin:0 0 16px}label{display:block;font-size:13px;color:var(--muted);margin-top:12px}input{width:100%;height:38px;margin-top:4px;padding:0 10px;border:1px solid var(--line);border-radius:8px;font-size:14px}button.primary{width:100%;height:40px;margin-top:16px;background:var(--brand);color:#fff;border:0;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer}button.primary:disabled{opacity:.5;cursor:default}.err{color:#dc2626;font-size:13px;margin-top:10px}.shell{padding:24px}.muted{color:var(--muted)}