.toc-indicator {
  position: fixed;
  left: 20px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 1000;
}

.toc-indicator-item {
  width: 4px;
  height: 12px;
  background: #ccc;
  margin: 6px 0;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
}

.toc-indicator-item.h2 { height: 16px; }
.toc-indicator-item.h3 { height: 12px; margin-left: 8px; width: 3px; }
.toc-indicator-item.h4 { height: 8px; margin-left: 16px; width: 2px; }

.toc-indicator-item.active {
  background: #108adc;
}

.toc-indicator-item:hover {
  background: #666;
}

.toc-tooltip {
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  background: white;
  padding: 2px 8px;
  border-radius: 3px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
  font-size: 12px;
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.2s;
  pointer-events: none;
}

.toc-indicator-item:hover .toc-tooltip {
  opacity: 1;
}

@media (max-width: 768px) {
  .toc-indicator {
    left: 10px;
  }
  .toc-tooltip {
    display: none;
  }
}