site.css

// add arrows up/down for sorted-table columns
.table > thead > tr > th {
  position: relative;
  cursor: pointer;
  padding-left: 20px;
}

.table th:before {
  content: "";
  border-right: 3px solid transparent;
  border-bottom: 3px solid #b6b6b6;
  border-left: 3px solid transparent;
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
  margin-top: -2px;
}

.table th:after {
  content: "";
  border-right: 3px solid transparent;
  border-top: 3px solid #b6b6b6;
  border-left: 3px solid transparent;
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
  margin-top: 3px;
}

.table .asc:before {
  border-bottom-color: #111;
}

.table .desc:after {
  border-top-color: #111;
}