body {
  background: gray;
}

.bar {
  border-radius: 1em 0 0 1em;
  background: #fff;
  height: 1em;
  width: 20%;
  margin: 1em;
  border: .5em solid #fff;
  border-right: 0;
  position: relative;
  float: left;
}


.bar + .bar {
  border-radius: 0;
  border-left: 0;
  margin-left: 1.25em;
  z-index: -2;
}

.bar + .active.bar {
  z-index: auto;
}

.bar:after {
  content: '';
  display: block;
  width: 2.5em;
  position: absolute;
  right: -2.9em;
  top: -1.25em;
  height: 2.5em;
  border: .5em solid #fff;
  background: #fff;
  border-radius: 50%;
  z-index: -1;
}



.active.bar,
.active.bar:after {
  background: orange;
}