.page {
    width: 216mm;
    min-height: 279mm;
}

.previewmap {
    width: 175mm !important;
    height: 239mm !important;
    /* .page height -40mm (20 off top/bottom) */
}

@page {
    size: Letter;
}

@media print {
    html,
    body {
        width: 216mm;
        height: 279mm;
    }
}