主内容区
  

.sidebar {
  width: 250px;
  background: #333;
  color: white;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  transform: translateX(0);
  transition: transform 0.3s ease;
  z-index: 1000;
}

.sidebar.collapsed {
  transform: translateX(-250px);
}

.content {
  margin-left: 250px;
  transition: margin-left 0.3s ease;
}

.sidebar.collapsed ~ .content {
  margin-left: 0;
}

function toggleSidebar() {
  document.getElementById('sidebar').classList.toggle('collapsed');
}

@keyframes slideIn {
  from {
    transform: translateX(-250px);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes slideOut {
  from {
    transform: translateX(0);
    opacity: 0;
  }
  to {
    transform: translateX(-250px);
    opacity: 1;
  }
}

.sidebar.animate-in {
  animation: slideIn 0.4s forwards;
}

.sidebar.animate-out {
  animation: slideOut 0.4s forwards;
}