Timeline styles/styles.css

table.timeline, table.timeline tbody {
    display: block;
}

table.timeline tr {
	position: relative;
	margin-left: 8px;
	padding: var( --space-xs ) var( --space-xs ) var( --space-xs ) 20px;
    display: flex;
    flex-direction: column;
    border-top-right-radius: var( --border-radius--small );
    border-bottom-right-radius: var( --border-radius--small );
}

table.timeline tr:before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    display: block;
    width: 1px;
    background-color: var( --border-color-base--darker );
}

table.timeline tr td:first-child {
    font-size: 1rem;
    font-weight: var( --font-weight-semibold );
    color: var( --color-base--emphasized );
}

table.timeline tr td:first-child:before {
	content: "";
    width: 8px;
    height: 8px;
    display: block;
    background-color: var( --color-base--subtle );
    border-radius: 100%;
    position: absolute;
    left: -4px;
    margin-top: 8px;
}

table.timeline tr td {
	padding: 0;
}

table.timeline tr + tr {
	border-top: 0;
}