.mindmap article {
  padding: 8px;
  border: 1px solid black;
}
.mindmap li {
  list-style: none;
  display: flex;
  align-items: center;
  box-sizing: border-box;
  margin: 16px;
  line-height: 1;
  position: relative;
}
.mindmap li > ul:before {
  content: "";
  border: 1px solid black;
  border-top: none;
  border-left: none;
  width: calc(16px - 2px);
  height: 0px;
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
}
.mindmap li:before {
  content: "";
  border: 1px solid black;
  border-top: none;
  border-left: none;
  width: 16px;
  height: 0px;
  position: absolute;
  left: calc(-16px - 1px);
}
.mindmap li:after {
  content: "";
  border: 1px solid black;
  border-top: none;
  border-left: none;
  width: 0px;
  height: calc(100% / 2 + 16px);
  position: absolute;
  left: calc(-16px - 2px);
}
.mindmap li:first-of-type:after {
  top: 50%;
}
.mindmap li:last-of-type:after {
  bottom: 50%;
}
.mindmap li ul {
  padding: 0 0 0 16px;
  position: relative;
}
.mindmap > li:after, .mindmap > li:before {
  display: none;
}