body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f7fafc;
    color: #1f2937;
}

main {
    max-width: 720px;
    margin: 64px auto;
    padding: 24px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 12px;
}