react-timeline-component/app/TimelineComponent.css

SVG Timeline built in react. For showing dates on a line.

.timelineComponentPopover:after, .timelineComponentPopover:before {
  bottom: 100%;
  left: 50%;
  border: solid transparent;
  content: " ";
  height: 0;
  width: 0;
  position: absolute;
  pointer-events: none;
}

.timelineComponentPopover:after {
  border-color: rgba(255, 255, 255, 0);
  border-bottom-color: #ffffff;
  border-width: 10px;
  margin-left: -10px;
}
.timelineComponentPopover:before {
  border-color: rgba(245, 0, 0, 0);
  border-bottom-color: #2A2A2A;
  border-width: 11px;
  margin-left: -11px;
}