body { background-color:#fafafa; font-family:'Roboto';}

.box {
  position: absolute;
  display: block;
  border: 2px black solid;
  width: 200px;
  height: 100px;
  padding: 5px;
}
.box:before {
  content: attr(id);
  display: block;
  background: black;
  color: #fff;
  display: inline-block;
  padding: 5px;
  position: absolute;
  top: -30px;
  left: -2px;
}
#box1 {
  left: 20px;
  top: 20px;
  border-color: green;
}
#box2 {
  left: 350px;
  top: 100px;
  border-color: red;
}
#box3 {
  left: 100px;
  top: 200px;
  height: 350px;
  border-color: blue;
}
#box4 {
  left: 500px;
  top: 350px;
}
#chained-box-content {
  display: none;
}