.sleek-tooltip {
  position: absolute;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px); /* Modern frosted-glass effect */
  color: #1a1a1a;
  padding: 8px 14px;
  border-radius: 8px;
  font-family: 'Inter', -apple-system, sans-serif;
  font-size: 13px;
  font-weight: 500;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08), 0 2px 8px rgba(0, 0, 0, 0.04);
  pointer-events: none; /* Prevents the tooltip from flickering under the mouse */
  opacity: 0;
  transform: translate(-50%, -100%) scale(0.95);
  transition: opacity 0.2s ease, transform 0.2s ease;
  z-index: 9999;
  white-space: nowrap;
}

/* Class added via JavaScript on hover */
.sleek-tooltip.visible {
  opacity: 1;
  transform: translate(-50%, -120%) scale(1); /* Offsets it smoothly above the marker */
}