example.css

.container .spacer, .container .sub_element, .container .numeric_content, .container .string_content  {
    padding-left: 12px;  
    position: relative;   
}
.container .spacer::before, .container .spacer::after,
.container .sub_element::before, .container .sub_element::after, 
.container .numeric_content::before, .container .numeric_content::after, 
.container .string_content::before, .container .string_content::after{
    content: '';
    position: absolute;
    left: 0;
}
.container .sub_element::before, .container .numeric_content::before, .container .string_content::before{
    border-top: 1px solid #999;
    top: 12px;
    width: 12px;
    height: 0;    
}
.container .spacer::after, .container .sub_element::after, .container .numeric_content::after, .container .string_content::after{
    border-left: 1px solid #999;
    height: 100%;
    width: 0px;
    top: -12px; 
}
.spacer::after, .sub_element::after, .numeric_content::after, .string_content::after{
    top: 12px;
}
.sub_element:last-child::after {
    height: 24px;
}
.needed {
    border-color: red;
    border-width: 2;
}
.duplicate {
    border-color: green;
    border-width: 2;
}
input {
    border-width: 0;
    background-color: transparent;
    padding-left: 5px;
    height: 24px;
}
input:disabled {
    padding-left: 10px;
}
.spacer {
    height: 5px;
}
.additional {
    background-color: white;
}
select {
    height: 22px;
    padding:3px;
    margin: 0;
    -webkit-border-radius:4px;
    -moz-border-radius:4px;
    border-radius:4px;
    -webkit-box-shadow: 0 3px 0 #ccc, 0 -1px #bbb inset;
    -moz-box-shadow: 0 3px 0 #ccc, 0 -1px #bbb inset;
    box-shadow: 0 3px 0 #ccc, 0 -1px #bbb inset;
    background: #eee;
    color:#444;
    border:none;
    outline:none;
    display: inline-block;
    -webkit-appearance:none;
    -moz-appearance:none;
    appearance:none;
    cursor:pointer;
}