marker styling

app.css

/* Marker */
.marker {
  height: 15px;
  width: 15px;
  border-radius: 50%;
  background-color: blue;
  cursor: pointer;
}

.marker:before,
.marker:after {
  content: '';
  display: block;
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  border: 1px solid blue;
  border-radius: 50%;
}

.marker:before {
  animation: ripple 2s linear infinite;
}

.marker:after {
  animation: ripple 2s linear 1s infinite;
}

@keyframes ripple {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.3);
    opacity: 1;
  }
  100% {
    transform: scale(1.6);
    opacity: 0;
  }
}