body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}
header {
    background-color: #333;
    color: white;
    padding: 1rem;
    text-align: center;
}
.father-nav {
    position: relative;
    z-index: 100;
}
.navbar {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    background-color: #444;
    flex-grow: 1;
}
.navbar > li {
    position: relative;
}
.navbar a {
    display: block;
    color: white;
    text-decoration: none;
    padding: 1rem;
    transition: background-color 0.3s;
}
.navbar a:hover {
    background-color: #555;
}
.dropdown-menu {
    list-style-type: none;
    margin: 0;
    padding: 0;
    position: absolute;
    top: 100%;
    left: 0;
    background-color: #444;
    display: none; /* 默认隐藏 */
    min-width: 150px;
    box-shadow: 0px 4px 6px rgba(0, 0, 0, 0.2);
}
.dropdown-menu li a {
    padding: 0.8rem;
    white-space: nowrap;
}
    
.dropdown:hover .dropdown-menu {
    display: block; /* 悬停时显示下拉菜单 */
}
    
.dropdown-menu li a:hover {
    background-color: #555;
}
/* 账户选项样式 */
.navbar-right {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    position: absolute;
    right: 6rem;
    top: 0;
}
.navbar-right li {
    position: relative;
}
.navbar-right a {
    display: block;
    color: white;
    text-decoration: none;
    padding: 1rem;
    transition: background-color 0.3s;
}
.navbar-right a:hover {
    background-color: #555;
}
.navbar-right .dropdown-menu {
    list-style-type: none;
    margin: 0;
    padding: 0;
    position: absolute;
    top: 100%;
    left: 0;
    background-color: #444;
    display: none; /* 默认隐藏 */
    min-width: 150px;
    box-shadow: 0px 4px 6px rgba(0, 0, 0, 0.2);
}
.navbar-right .dropdown:hover .dropdown-menu {
    display: block;
}