.top-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    background-color: #333; /* 深灰色背景 */
    padding: 10px 0px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2); /* 添加阴影，增加立体感 */
    position: fixed;
    top: 0;
    z-index: 1000;
}
.top-nav .back-button {
    color: white;
    text-decoration: none;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
	width: 80px;
}
.top-nav .title {
    font-size: 18px;
    font-weight: bold;
	color: white;
	margin-left: -80px;
    flex-grow: 1; /* 让标题占据剩余空间 */
    text-align: center; /* 标题居中显示 */
}