.left-panel {
  width: 250px;
  height: 100vh;
  background: #f8f9fa;
  border-right: 1px solid #dee2e6;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.left-panel-header {
  padding: 20px;
  background: #fff;
  border-bottom: 1px solid #dee2e6;
}

.left-panel-header h2 {
  margin: 0;
  font-size: 18px;
  color: #333;
}

.left-panel-content {
  flex: 1;
  overflow-y: auto;
  padding: 10px 0;
}

.l1-item {
  margin-bottom: 2px;
}

.l1-header {
  padding: 12px 20px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #fff;
  transition: background-color 0.2s;
  user-select: none;
}

.l1-header:hover {
  background: #e9ecef;
}

.l1-header.selected {
  background: #007bff;
  color: white;
}

.l1-name {
  flex: 1;
  font-weight: 500;
}

.l1-count {
  margin-left: 8px;
  font-size: 12px;
  opacity: 0.7;
}

.expand-icon {
  margin-left: 8px;
  transition: transform 0.3s;
  font-size: 10px;
}

.expand-icon.expanded {
  transform: rotate(180deg);
}

.l2-dropdown-container {
  background: #f1f3f5;
  border-top: 1px solid #dee2e6;
}

.l2-item {
  padding: 10px 20px 10px 40px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #fff;
  border-bottom: 1px solid #f1f3f5;
  transition: background-color 0.2s;
  user-select: none;
}

.l2-item:hover {
  background: #e9ecef;
}

.l2-item.selected {
  background: #0056b3;
  color: white;
}

.l2-name {
  flex: 1;
  font-size: 14px;
}

.l2-count {
  margin-left: 8px;
  font-size: 12px;
  opacity: 0.7;
}