table {
    position: relative;
    width: 80ch;
    margin: 2em 0;
}

thead::after {
    content: "";
    width: 100%;
    height: 1px;
    position: absolute;
    background: black;
}

td, tr, th {
    margin: 0;
    padding: .2em;
    position: relative;
}

th:first-child {
    width: 30%;
}

th:last-child {
    width: 70%;
}

td:last-child::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    width: 1px;
    height: calc(100% + .4em);
    background: black;
}