.wrapper
  ul
    li.item 
      span.text Item 1
      ul.sub
        li.item
          span.text Item 1-1
        li.item
          span.text Item 1-2
    li.item
      span.text Item 2
      ul.sub
        li.item
          span.text Item 2-1
          ul.sub
            li.item
             span.text Item 2-1-1
            li.item
             span.text Item 2-1-2
             ul.sub
              li.item
               span.text Item 2-1-2-1
              li.item
               span.text Item 2-1-2-2
              li.item
               span.text Item 2-1-2-3
              li.item
               span.text Item 2-1-2-4
        li.item
          span.text Item 2-2
          ul.sub
            li.item
              span.text Item 2-2-1
            li.item
              span.text Item 2-2-2
    li.item
      span.text Item 3
      ul.sub
        li.item
          span.text Item 3-1
        li.item
          span.text Item 3-2
          ul.sub
            li.item
              span.text Item 3-1-1
              ul.sub
                li.item
                  span.text Item 3-1-1-1
        
View Compiled
:root {
  --textcolor: #eee9dc;
  --bgcolor: #272727;
  --textbg: rgba(100,100,100,0.1);
  --linecolor: #809BBD;
}

*, *:before, *:after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  margin: 0;
}

body {
  min-width: 1200px;
  padding: 0 50px;
  color: var(--textcolor);
  font: 16px 'Open sans';
  text-transform: uppercase;
  background: var(--bgcolor);
}

.wrapper {
  position: relative;
}

ul.sub {
  position: relative;
  margin-left: 200px;
}

ul.sub:before {
  content: '';
  font-size: 40px;
  width: 40px;
  border-top: 2px solid var(--linecolor);
  position: absolute;
  left: -50px;
  top: 50%;
  margin-top: 1px;
}

li {
  position: relative;
  min-height: 60px;
  list-style-type: none;
}

li > span {
  display: block;
  min-width: 150px;
  padding: 5px 10px;
  line-height: 20px;
  text-align: center;
  border: 2px solid var(--linecolor);
  border-radius: 5px;
  position: absolute;
  left: 0;
  top: 50%;
  margin-top: -15px;
  background: var(--textbg);
}

li:before {
  content: "";
  height: 100%;
  border-left: 2px solid var(--linecolor);
  position: absolute;
  left: -50px;
}
li:after {
  content: "";
  width: 50px;
  border-top: 2px solid var(--linecolor);
  position: absolute;
  left: -50px;
  top: 50%;
  margin-top: 1px;
}

li:first-child:before {
  width: 10px;
  height: 50%;
  top: 50%;
  margin-top: 2px;
  border-radius: 5px 0 0 0;
}
li:first-child:after {
  height: 10px;
  border-radius: 5px 0 0 0;
}
li:last-child:before {
  width: 10px;
  height: 50%;
  border-radius: 0 0 0 5px;
}
li:last-child:after {
  height: 10px;
  border-top: none;
  border-bottom: 2px solid var(--linecolor);
  border-radius: 0 0 0 5px;
  margin-top: -9px;
}

li:only-child:before {
  border:0;
}

li:only-child:after {
  border-radius:0;
  width: 90px;
  margin-left: -40px;
  border-bottom: 2px solid var(--linecolor);
  margin-top: -7px;
}

External CSS

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External JavaScript

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