.dataTables_wrapper > div.row:nth-child(2) > div {
    max-height: calc(100vh - 50px);
    overflow-y: auto;
}

thead {
    position: sticky;
    top: 0;
}
table tbody th {
    position: relative;
}

table thead th {
    position: sticky;
}

table thead th:first-child {
    position: sticky;
    left: 0;
    z-index: 2;
}