body { font-family: Arial, "Microsoft JhengHei", sans-serif; line-height:1.6; padding:24px; }
    .wrap { max-width: 600px; margin: 0 auto; }
    .card { background:#fff; border:1px solid #ccc; border-radius:12px; padding:20px; }
    h1 { margin:0 0 12px 0; font-size:22px; }
    label { display:block; margin-top:12px; font-weight:600; }
    input { width:100%; padding:8px; margin-top:6px; border:1px solid #999; border-radius:6px; }
    .submit { margin-top:16px; padding:10px 14px; border:0; border-radius:8px; background:#111827; color:#fff; cursor:pointer; }
    .error { background:#ffecec; color:#c00; border:1px solid #f5a9a9; padding:12px; border-radius:8px; margin-top:12px; }
    .result { background:#f8f8f8; border:1px solid #ccc; border-radius:8px; padding:12px; margin-top:16px; }