style.css

.group {
    min-height: 100px;
    position: relative;
    padding-left: 15px;
    margin: 10px;
    margin-top: 20px;
    border: 1px solid rgb(212, 218, 218);
    border-radius: 6px;
    background-color: rgb(236, 243, 243);
}
.group-container{
    min-height: 80px;
}
.rule-definition>.group>.options .remove-group,
.rule-definition>.group>.options .drag-handler {
    display: none;
}
.rule-definition>.group {
    margin: 0px;
}

.rule {
    position: relative;
    padding: 10px;
    margin: 15px;
    background-color: #ffffff;
    border: 1px solid #c5e3c5;
}

.rule-definition {
    padding: 10px;
    margin: auto;
    width: 60%;
    min-height: 600px;
    background-color: white;
    border: 1px solid #b3b3b3;
}

.group .rule::after,
.group .rule::before,
.group-container .group::after,
.group-container .group::before {
    border-color: #adadad;
}

.group-container .group::after,
.group-container .group::before {
    content: '';
    position: absolute;
    left: -11px;
    width: 9px;
    height: calc(50% + 20px);
    border-style: solid
}

.group-container .group::before {
    top: -9px;
    border-width: 0 0 2px 2px;
}

.group-container .group::after {
    top: calc(50%);
    border-width: 0 0 0 2px;
}

.group-container .group:first-child::before {
    top: -23px;
    height: calc(50% + 40px);
}

.group-container .group:last-child::before {
    border-radius: 0 0 0 4px;
}

.group-container .group:last-child::after {
    display: none;
}

/**/

.group .rule::after,
.group .rule::before {
    content: '';
    position: absolute;
    left: -16px;
    width: 14px;
    height: calc(50% + 14px);
    border-style: solid
}

.group .rule::before {
    top: -13px;
    border-width: 0 0 2px 2px;
}

.group .rule::after {
    top: calc(50%);
    border-width: 0 0 0 2px;
}

.group .rule:first-child::before {
    top: -18px;
    height: calc(50% + 20px);
}

.group .rule:last-child::before {
    border-radius: 0 0 0 4px;
}

.group .rule:last-child::after {
    display: none;
}

.options {
    margin-top: 10px;
    margin-left: -10px;
}

.body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.group .dragging{
    position: fixed;
    opacity: .5;
    z-index: 100;
}

.group .rule-placeholder{
    position: relative;
    margin: 4px 0;
    border-radius: 5px;
    padding: 5px;
    background: rgba(255,255,255,.9);
    border: 1px dashed #bbb;
    opacity: .7;
}