.fn {
  position: relative;
}

.fn button {
  border: 0;
  padding: 0 2px;
  background: none;
  color: #2463a6;
  font-size: 0.7em;
  vertical-align: super;
  cursor: pointer;
}

.fn-popup {
  position: absolute;
  z-index: 1000;
  bottom: 1.8em;
  left: -0.8em;
  width: 320px;
  padding: 12px;
  border: 1px solid #ddd;
  border-radius: 6px;
  background: white;
  color: #222;
  box-shadow: 0 4px 20px #0002;
  font: 14px/1.5 sans-serif;
}

.fn-popup[hidden] {
  display: none;
}