.tip { position: relative; display: inline-block; }

.tip-btn {
  width: 1.4em; height: 1.4em;
  padding: 0;
  border: 1px solid currentColor;
  border-radius: 50%;
  background: none;
  font: italic bold 0.8em serif;
  line-height: 1;
  cursor: pointer;
  position: relative;
  text-transform: none;
}

.tip-text {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  z-index: 10;
  width: max-content;
  max-width: min(260px, 80vw);
  padding: 8px 10px;
  border-radius: 6px;
  background: #222;
  color: #fff;
  font-size: 0.9rem;
  line-height: 1.4;
  box-shadow: 0 2px 8px rgba(0,0,0,.25);
}