/* 设置导航栏 */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 5px 10px;
    background-color: #add8e6;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 10;
    width: 100%;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: top 0.3s;
}

header .logo img {
    width: 50%;
    display: block;
    margin-left: 0;
}

nav ul {
    list-style: none;
    display: flex;
    align-items: center;
}

nav ul li {
    margin: 0px 20px;
    position: relative;
}

nav ul li a {
    text-decoration: none;
    padding: 12px 6px;
    color: black;
    font-size: 16px;
    font-weight: bold;
    border-radius: 10px;
    border: none;
    transition: background-color 0.3s ease, color 0.3s ease;
}

nav ul li a:hover {
    background-color: #bdd8ff;
    color: #fff;
}

nav ul li a.active {
    background-color: #bdd8ff;
    color: #fff;
}

/* 下拉菜单 */
nav ul li .dropdown {
    cursor: pointer;
    display: flex;
    align-items: center;
}

nav ul li .dropdown .arrow {
    margin-left: 5px;
    transition: transform 0.3s ease;
}

nav ul li .dropdown:hover .arrow {
    transform: rotate(180deg);
}

nav ul li .dropdown-content {
    display: none;
    position: absolute;
    background-color: #fff;
    min-width: 160px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
    z-index: 1;
}

nav ul li .dropdown-content li {
    padding: 10px 20px;
}

nav ul li .dropdown-content li a {
    color: #000;
}

/* 鼠标悬停时显示下拉菜单 */
nav ul li:hover .dropdown-content {
    display: block;
}

/* 汉堡菜单 */
.hamburger-menu {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 25px;
    cursor: pointer;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.hamburger-menu .line {
    height: 5px;
    background-color: gray;
    border-radius: 3px;
    transition: background-color 0.3s ease;
}

/* 移动端菜单展示 */
@media (max-width: 768px) {
    nav ul {
        display: none;
        flex-direction: column;
        width: 100%;
        position: absolute;
        top: 50px;
        left: 0;
        background-color: #add8e6;
        padding: 10px 0;
    }

    nav.active ul {
        display: flex;
    }

    nav ul li {
        margin: 10px 0;
        text-align: center;
    }

    nav ul li a {
        padding: 10px 20px;
    }

    .hamburger-menu {
        display: flex; /* 在小屏幕上显示汉堡按钮 */
    }
}