.app-container {
	height: 100vh; /* 高度設置為視窗高度 */
	display: flex;
	flex-direction: column;
  }
  
  nav {
	background-color: #f0f0f0;
	padding: 10px;
	position: sticky;
	top: 0;
	z-index: 1000;
	text-align: center; /* 確保按鈕居中 */
  }
  
  nav button {
	margin: 0 10px; /* 按鈕間距 */
  }
  
  .content {
	flex: 1;
	overflow-y: auto;
	display: flex;
	flex-direction: column; /* 垂直排列 */
	align-items: center;     /* 垂直居中 */
	justify-content: center; /* 水平居中 */
	padding: 20px;
  }