arangodb/js/apps/system/aardvark/frontend/scss/_tooltips.scss

.tooltip-inner {
  max-width: 300px !important;
  word-wrap: break-word !important;
  white-space: normal !important;
}

.indexTooltip {
  color: $c_btn_inverse;
  &:hover {
    color: $c_black;
  }
  span.arangoicon {
    font-size: 18px !important;
  }
}