th, td {
    border: 1px solid black;
    padding: 5px;
}

table {
    display: inline-table;
    border-collapse: collapse;
}

th {
    font-weight: bold;
}

table.colgroup-2 tr :nth-child(2n+3), table.colgroup-3 tr :nth-child(3n+4) {
    border-left-style: double;
    border-left-width: 3px;
}