/* General Reset & Base Styles */
body {
    margin: 0;
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f4f4f4;
    padding-top: 4.5rem; /* 为固定页头增加内边距，防止内容被遮挡 */
}
body.no-scroll {
    overflow: hidden;
}
a {
    text-decoration: none;
    color: inherit;
}
ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

/* Header Styles */
.site-header {
    background-color: #003366; /* Primary color */
    color: #fff;
    padding: 1rem 0;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    position: fixed; /* 页头悬浮 */
    top: 0;
    width: 100%;
    z-index: 1000; /* 确保它位于其他内容之上 */
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative; /* 为手机端汉堡菜单的绝对定位提供参考 */
}

.site-header .logo {
    font-size: 2.2rem;
    font-weight: bold;
    color: #FFCC00; /* Secondary color for logo */
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.3s ease;
}

.site-header .logo:hover {
    color: #fff;
}

.main-nav .nav-list {
    display: flex;
    gap: 1.5rem;
}

.main-nav .nav-list li a {
    color: #fff;
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
    transition: color 0.3s ease;
}

.main-nav .nav-list li a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background-color: #FFCC00; /* Secondary color */
    transition: width 0.3s ease;
}

.main-nav .nav-list li a:hover::after,
.main-nav .nav-list li a.active::after {
    width: 100%;
}

.main-nav .nav-list li a:hover,
.main-nav .nav-list li a.active {
    color: #FFCC00; /* Secondary color */
}

/* 新增的注册/登录按钮样式 */
.header-actions {
    display: flex;
    gap: 1rem;
    margin-left: 1.5rem; /* 与导航之间的间距 */
}

.header-actions .btn {
    display: inline-block;
    padding: 0.7rem 1.2rem;
    border-radius: 5px;
    font-weight: bold;
    text-transform: uppercase;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    white-space: nowrap; /* 防止按钮文本换行 */
}

.header-actions .btn-register {
    background-color: #FFCC00; /* Secondary color */
    color: #003366; /* Primary color */
    border: 2px solid #FFCC00;
}

.header-actions .btn-register:hover {
    background-color: #e6b800;
    border-color: #e6b800;
    color: #001f3f; /* Darker primary */
}

.header-actions .btn-login {
    background-color: transparent;
    color: #FFCC00; /* Secondary color */
    border: 2px solid #FFCC00;
}

.header-actions .btn-login:hover {
    background-color: #FFCC00;
    color: #003366; /* Primary color */
}

.hamburger-menu {
    display: none; /* 桌面端隐藏 */
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    position: relative;
    z-index: 1001; /* 确保它位于其他内容之上 */
}

.hamburger-menu .bar {
    display: block;
    width: 25px;
    height: 3px;
    background-color: #fff;
    margin: 5px auto;
    transition: all 0.3s ease-in-out;
}

/* Footer Styles */
.site-footer {
    background-color: #003366; /* Primary color */
    color: #fff;
    padding: 3rem 0 1.5rem;
    font-size: 0.9rem;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 2rem;
}

.footer-column {
    flex: 1;
    min-width: 250px;
}

.footer-column h3 {
    color: #FFCC00; /* Secondary color */
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.footer-column p,
.footer-nav li a {
    color: #ccc;
    line-height: 1.8;
    transition: color 0.3s ease;
}

.footer-nav li a:hover {
    color: #FFCC00; /* Secondary color */
}

.footer-bottom {
    max-width: 1200px;
    margin: 2rem auto 0;
    padding: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    position: relative;
}

.footer-bottom p {
    color: #ccc;
}

#scrollToTop {
    background-color: #FFCC00; /* Secondary color */
    color: #003366; /* Primary color */
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 1.5rem;
    cursor: pointer;
    position: absolute;
    bottom: 1rem; /* Adjust as needed */
    right: 1.5rem;
    display: none; /* Hidden by default, shown with JS */
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    transition: background-color 0.3s ease;
}

#scrollToTop:hover {
    background-color: #e6b800; /* Slightly darker secondary */
}

/* 响应式样式 */
@media (max-width: 768px) {
    .site-header {
        padding: 0; /* 手机端移除 site-header 的垂直内边距，由 header-container 管理 */
    }

    .header-container {
        flex-direction: column; /* 手机端堆叠元素 */
        align-items: center; /* 手机端水平居中 */
        padding: 1rem 1rem; /* 手机端重新设置整体内边距 */
        /* justify-content: space-between 在 flex-direction: column 时不再适用 */
    }

    /* 手机端LOGO居中 */
    .site-header .logo {
        font-size: 2rem; /* 手机端LOGO字体略小 */
        order: 1; /* 在列中排在第一位 */
        width: 100%; /* 占据全部宽度 */
        text-align: center; /* 文本居中 */
        margin-bottom: 0.5rem; /* LOGO下方留出间距 */
    }

    /* 手机端汉堡菜单与LOGO在同一栏（通过绝对定位实现） */
    .hamburger-menu {
        display: block; /* 手机端显示汉堡菜单 */
        position: absolute; /* 相对于 header-container 绝对定位 */
        right: 1rem; /* 距离右侧边缘1rem */
        top: 1.5rem; /* 垂直方向上与LOGO视觉对齐 */
    }

    /* 手机端按钮并排呈现在LOGO下面的独立区域中间位置 */
    .header-actions {
        order: 2; /* 在列中排在第二位（LOGO下方） */
        display: flex;
        justify-content: center; /* 按钮水平居中 */
        width: 100%;
        margin-top: 0; /* 重置桌面端的外边距 */
        margin-left: 0; /* 重置桌面端的外边距 */
        gap: 1rem;
        padding-bottom: 0.5rem; /* 按钮下方留出间距 */
    }

    /* 手机端主导航 */
    .main-nav {
        order: 3; /* 在列中排在第三位，但由于其 fixed 定位，不影响文档流 */
        position: fixed;
        top: 0;
        left: -100%; /* 默认在屏幕外 */
        width: 70%;
        height: 100%;
        background-color: #003366; /* Primary color */
        padding-top: 5rem;
        transition: left 0.3s ease-in-out;
        z-index: 1000;
        box-shadow: 2px 0 5px rgba(0, 0, 0, 0.3);
    }

    .main-nav.active {
        left: 0; /* 滑入屏幕 */
    }

    .main-nav .nav-list {
        flex-direction: column;
        align-items: flex-start;
        padding: 1rem 1.5rem;
    }

    .main-nav .nav-list li {
        width: 100%;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .main-nav .nav-list li:last-child {
        border-bottom: none;
    }

    .main-nav .nav-list li a {
        display: block;
        padding: 1rem 0;
        width: 100%;
    }

    .hamburger-menu.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger-menu.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger-menu.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .footer-container {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .footer-column {
        min-width: unset;
        width: 100%;
        margin-bottom: 1.5rem;
    }

    .footer-column:last-child {
        margin-bottom: 0;
    }

    #scrollToTop {
        right: 1rem;
        bottom: 1rem;
    }

    @media (max-width: 400px) {
        .header-actions .btn {
            padding: 0.7rem 0.8rem; /* 更小屏幕下按钮内边距和字体调整 */
            font-size: 0.8rem;
        }
    }
}