/* this part adds an icon after DOI and xtb-docs links, using FontAwesome*/
a[href^="https://doi."]:after, a[href^="https://xtb-docs."]:after {
    content: "\f08e";
    font-family: FontAwesome;
    font-weight: normal;
    font-style: normal;
    display: inline-block;
    text-decoration: none;
    padding-left: 3px;
}



 /* Tooltip container */
.tooltip {
  position: relative;
  display: inline-block;
  border-bottom: 1px dotted black; /* If you want dots under the hoverable text */
}

/* Tooltip text */
.tooltip .tooltiptext {
  visibility: hidden;
  width: 200px;
  background-color: #555;
  color: #fff;
  text-align: center;
  padding: 5px 0;
  border-radius: 6px;

  /* Position the tooltip text */
  position: absolute;
  z-index: 1;
  top: 110%;
  left: 0%;
  margin-left: -100px;

  /* Fade in tooltip */
  opacity: 0;
  transition: opacity 0.3s;
}

/* Tooltip arrow */
.tooltip .tooltiptext::after {
  content: "";
  position: absolute;
  bottom: 100%;
  left: 60%;
  margin-left: -5px;
  border-width: 5px;
  border-style: solid;
  border-color: transparent transparent #555 transparent;
}

/* Show the tooltip text when you mouse over the tooltip container */
.tooltip:hover .tooltiptext {
  visibility: visible;
  opacity: 0.9;
}