.custom-tooltip {
  position: absolute;
  padding: 6px 10px;
  background-color: rgba(0, 0, 0, 0.85);
  color: #fff;
  border-radius: 4px;
  font-size: 13px;
  pointer-events: none; /* 讓滑鼠穿透，不影響點擊 */
  z-index: 999;
  visibility: hidden;
  opacity: 0;
  transition: opacity 0.15s;
  white-space: nowrap;
}

.custom-tooltip {
    transition: opacity 0.2s, left 0.1s ease-out, top 0.1s ease-out;
    /* 確保不會因為視窗變小而換行導致高度變形 */
    white-space: nowrap; 
}

.custom-tooltip.show {
  visibility: visible;
  opacity: 1;
}

/* 小箭頭 */
.custom-tooltip::after {
  content: "";
  position: absolute;
  top: 100%; 
  left: 50%;
  transform: translateX(-50%);
  border-width: 5px;
  border-style: solid;
  border-color: rgba(0, 0, 0, 0.85) transparent transparent transparent;
}