.columns {
    position: sticky;
    top: 0;
    background-color: #ffffff;
    z-index: 2;
}

/* Keep DataTables sorting available without displaying its order arrows. */
table.dataTable thead > tr > th span.dt-column-order,
table.dataTable thead > tr > td span.dt-column-order,
table.dataTable thead > tr > th::before,
table.dataTable thead > tr > th::after,
table.dataTable thead > tr > td::before,
table.dataTable thead > tr > td::after {
    display: none !important;
    content: none !important;
}