* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', sans-serif;
            color: white;
            overflow-x: hidden;
        }
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 70px;
    background-color: rgba(0, 0, 0, 0);
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 2000;
    padding: 0 30px;
    backdrop-filter: blur(10px);
    gap: 30px;
    transition: 1s
}

    .header:hover {
        background-color: rgba(0, 0, 0, 0.7);
        transition: 1s
    }

.logo {
    font-size: 22px;
    font-weight: bold;
    color: white;
    text-decoration: none;
    line-height: 1.2;
}

    .logo span {
        font-size: 13px;
        display: block;
        opacity: 0.8;
    }

/* 桌面顶部导航 */
.nav-links {
    display: flex;
    gap: 28px;
    font-size: 16px;
    font-weight: 500;
    margin-left: auto;
}

    .nav-links a {
        color: #eeeeee;
        text-decoration: none;
        display: block;
        font-size: 14px;
        height: 70px;
        line-height: 70px;
        transition: opacity 0.3s ease;
    }

        .nav-links a:hover {
            color: #ffffff;
        }

.dropdown {
    position: relative;
}

.dropdown-menu {
    display: none;
    position: fixed;
    left: 0px;
    right: 0px;
    background: rgba(121, 121, 121, 0.5);
    border-radius: 6px;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.4);
    padding: 8px 0;
    z-index: 2001;
    justify-content: center; /* 水平居中 */
    align-items: center; /* 垂直居中 */
    transition: 1s
}

    .dropdown-menu a {
        padding: 0px 20px;
        color: #eeeeee;
        font-size: 15px;
        display: inline-flex;
    }

        .dropdown-menu a:hover {
            color: #ffffff
        }

.dropdown:hover .dropdown-menu {
    display: flex;
    transition: 1s
}

/* 汉堡按钮（所有设备） */
.hamburger {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 21px;
    cursor: pointer;
    z-index: 2001;
}

    .hamburger span {
        display: block;
        height: 2px;
        width: 100%;
        background-color: white;
        border-radius: 2px;
        transition: all 0.3s ease;
    }

/* 手机模式：隐藏顶部完整菜单 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
}

/* === 全屏侧边导航 === */
.sidebar-nav {
    position: fixed;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100vh;
    background: #333333;
    color: white;
    padding-top: 80px;
    padding-left: 30px;
    padding-right: 30px;
    padding-bottom: 30px;
    transition: left 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
    z-index: 2002;
    overflow-y: auto;
}

    .sidebar-nav .dropdown {
        background: none;
    }

    .sidebar-nav.open {
        left: 0;
    }

    .sidebar-nav .close-btn {
        position: absolute;
        top: 25px;
        right: 30px;
        font-size: 28px;
        cursor: pointer;
        color: white;
    }

    /* 默认：手机模式下的垂直布局 */
    .sidebar-nav ul {
        list-style: none;
        display: block;
    }

    .sidebar-nav li {
        margin-bottom: 20px;
        position: relative;
    }

    .sidebar-nav > ul > li > a {
        font-size: 20px;
        font-weight: 500;
        color: white;
        text-decoration: none;
        display: flex;
        justify-content: space-between;
        align-items: center;
    }

    /* 二级菜单基础样式（初始隐藏） */
    .sidebar-nav .submenu {
        margin-top: 12px;
        padding-left: 15px;
        border-left: 1px solid #333;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }

/* === 手机模式：优化二级菜单纵向显示 === */
@media (max-width: 768px) {

    .sidebar-nav {
        background: #333333;
    }

        .sidebar-nav .submenu {
            padding-left: 20px !important;
            border-left: 2px solid #444 !important;
            margin-top: 10px !important;
        }

            .sidebar-nav .submenu a {
                display: block;
                padding: 10px 0;
                font-size: 14px;
                color: #bbb;
                opacity: 0.9;
                transition: opacity 0.2s;
                text-decoration: none;
            }

                .sidebar-nav .submenu a:hover {
                    opacity: 1;
                    color: white;
                }

            .sidebar-nav .submenu.open {
                max-height: 300px;
            }
}

/* === 桌面模式：全屏导航横向 + 二级菜单始终显示 === */
@media (min-width: 769px) {
    .sidebar-nav::after {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-image: url("/upload/Article/Theme/default/Template/images/bg.jpg");
        opacity: 0.1;
        background-repeat: no-repeat;
        background-size: cover;
        z-index: -1;
        content: ''
    }

    .sidebar-nav ul {
        display: flex;
        flex-wrap: wrap;
        gap: 40px;
        align-items: flex-start;
        max-width: 1200px;
        margin: 0 auto;
    }

    .sidebar-nav li {
        margin-bottom: 0;
        min-width: 160px;
    }

    /* 桌面模式下 submenu 始终可见 */
    .sidebar-nav .submenu {
        position: absolute;
        left: 0;
        top: 100%;
        width: 200px;
        padding-left: 0;
        border-left: none;
        border-radius: 6px;
        z-index: 2003;
        max-height: none !important;
        display: block !important;
        overflow: visible;
    }

        .sidebar-nav .submenu a {
            padding: 10px 0px;
            display: block;
            font-size: 17px;
            color: #aaa;
            text-decoration: none
        }

            .sidebar-nav .submenu a:hover {
                color: #de5c1d;
            }

    /* 隐藏箭头 */
    .sidebar-nav .arrow {
        display: none;
    }
}

/* 遮罩层 */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    z-index: 2001;
    display: none;
}

    .overlay.active {
        display: block;
    }