.error-marker {
  color: black;
  width: 6px !important;
  background-color: #ff0000;
}

.error-marker .error-message {
  display: none;
  position: absolute;
  background-color: #ddd;
  border: 1px solid #999;
  padding: 6px;
  width: 140px;
  left: 15px;
  top: -1em;
}

.error-marker:hover .error-message {
  display: block;
}