wiki-js-customization/srv/styles/tables.css

table {
    display: block;
    border-collapse: collapse;
    color: var(--override_gray) !important;
    margin-left: 0 !important;
    margin-right: 0 !important;
    overflow-x: auto
}

tr {
    border: none
}

th {
    border: solid .5px var(--override_gray) !important;
    border-bottom: solid 2px var(--override_gray) !important
}

td {
    border: solid .5px var(--override_gray) !important
}