body {
    margin: 0;                /* remove default browser margin */
    min-height: 100vh;        /* full viewport height */
    display: flex;
    flex-direction: column;
    align-items: center;      /* horizontal centering */
    justify-content: center;  /* vertical centering */
    text-align: center;
    font-family: 'Times New Roman', Times, serif;
}