morris.js/less/morris.core.less

.morris-popup {
  border-radius: 10px;
  position: absolute;
  z-index: 1000;
  padding: 6px;
  color: #666;
  background: rgba(255, 255, 255, 0.8);
  border: solid 2px rgba(230, 230, 230, 0.8);
}