ul {
	list-style: none;
}

.tree summary {
	cursor: pointer;
	list-style: none;
}

.tree summary::marker {
	display: none;
}

.tree summary::-webkit-details-marker {
	display: none;
}

ul li {
	position: relative;
	/* border: 1px solid green; */
}

ul li::before {
	position: absolute;
	left: -10px;
	top: 0px;
	content: "";
	border-left: 2px solid grey;
	border-bottom: 2px solid grey;
	width: 10px;
	height: 1em;
}

ul li::after {
	position: absolute;
	left: -10px;
	bottom: 0px;
	content: "";
	border-left: 2px solid grey;
	width: 10px;
	height: 100%;
}

ul li:last-child::after {
	display: none;
}

ul.tree>li:after,
ul.tree>li:before {
	display: none
}