.file-tree {
  background: #f9f9f9;
  border: 4px solid #f5f5f5;
  margin: 40px 0;
  padding: 16px 32px;
}
.file-tree .item {
  display: block;
  line-height: 32px;
  font-size: 15px;
  color: #5a5a5a;
}
.file-tree .children {
  padding-left: 30px;
  position: relative;
  overflow: hidden;
}
.file-tree .children .item {
  position: relative;
}
.file-tree .children .item:before {
  content: '';
  left: -18px;
  bottom: 16px;
  width: 16px;
  height: 9999px;
  position: absolute;
  border-width: 0 0 1px 1px;
  border-style: solid;
  border-color: #dbdbdb;
  border-radius: 0 0 0 3px;
}
.external {
  background: #f7f7f7;
}
.external::before {
  background: #e8e8e8;
}