Template:Timeline/styles.css

.timeline {
  width: 100%;
  height: 412px;
  padding: 20px;
  position:relative;
  box-sizing: border-box;
  background: #c8ccd1;
  overflow: auto;
  display: flex;
}
.timieline-title {
  font-size: 1.5em;
  font-weight: bold; 
}
.timeline-content {
  max-width: 300px;
  height: 125px;
  padding: 20px;
  flex-shrink: 0;
  flex-grow: 0;
  align-self: flex-start;
  background: #FFF;
  position: relative;
  border-radius: 10px;
  margin-right: 10px;
  box-shadow: 0px 0px 2px 2px rgba(0,0,0, 0.2);
}
.timeline-content:before {
  position: absolute;
  width: calc(100% + 14px);
  height: 4px;
  top: calc(100% + 10px);
  background: #FFF;
  content: "";
  left: -7px;
  border-radius: 5px;
}

.timeline-content:after {
  position: absolute;
  width: 4px;
  height: 25px;
  top: 100%;
  left: calc(50% - 10px);
  background: #FFF;
  content: "";
}
.timeline-period {
  position: absolute;
  top: calc(100% + 25px);
  background: #FFF;
  padding: 10px;
  width: 100px;
  text-align:center;
  border-radius: 10px;
  left: calc(50% - 70px);
  box-shadow: 0px 0px 2px 2px rgba(0,0,0, 0.2);
}
.timeline-period:before {
  width: 15px;
  height: 15px;
  background: #FFF;
  border-radius: 50%;
  content: "";
  position: absolute;
  top: -20px;
  left: calc(50% - 5.5px);
  z-index: 2;
}

.timeline-content:nth-child(even) {
  align-self: flex-end;
}
.timeline-content:nth-child(even):before {
    top: -15px; 
}
.timeline-content:nth-child(even):after {
    top: -25px;
}
.timeline-content:nth-child(even) .timeline-period {
  bottom: 115.25%;
  top: unset;
}
.timeline-content:nth-child(even) .timeline-period:before {
  top: calc(100% + 5px);
}