.gradient-tooltip {
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0, 0, 0, 0.8);
  color: white;
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 11px;
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.2s;
  z-index: 1001;
}
.gradient-tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 4px solid transparent;
  border-top-color: rgba(0, 0, 0, 0.8);
}
.gradient-tooltip.visible {
  opacity: 1;
}