/* ==========================================================
   header.css - 全站页头（site-header 组件）样式
   依赖 common.css 中定义的 CSS 变量
   ========================================================== */

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
    background: linear-gradient(to bottom, rgba(0, 0, 0, 0.28), transparent);
}

.site-header.is-fixed {
    background: rgba(248, 245, 242, 0.96);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-h);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
}

.logo-icon {
    width: 100px;
    height: auto;
    flex-shrink: 0;
    object-fit: contain;
    transition: opacity 0.3s;
}

.logo-icon-fixed {
    display: none;
}

.site-header.is-fixed .logo-icon-default {
    display: none;
}

.site-header.is-fixed .logo-icon-fixed {
    display: block;
}

.logo-cn {
    font-size: var(--fs-xl);
    font-weight: var(--fw-normal);
    letter-spacing: 4px;
    color: #fff;
    transition: color 0.3s;
}

.site-header.is-fixed .logo-cn {
    color: var(--color-text-dark);
}

/* .site-header.is-fixed .logo-icon 旧 SVG 颜色规则已弃用，改为图片切换 */

.nav-menu {
    display: flex;
    gap: 28px;
}

.nav-item {
    font-size: var(--fs-base);
    color: rgba(255, 255, 255, 0.92);
    padding: 6px 0;
    position: relative;
    letter-spacing: 2px;
    transition: color 0.3s;
}

.site-header.is-fixed .nav-item {
    color: var(--color-text-main);
}

.nav-item.active,
.nav-item:hover {
    color: #fff;
    text-decoration: underline;
}

/* 官网首页：导航“首页”字号加大一号（仅首页生效，不影响其他页面） */
body[data-page="index"] .nav-menu > .nav-item[href="/"] {
    font-size: var(--fs-lg);
}

.site-header.is-fixed .nav-item:hover,
.site-header.is-fixed .nav-item.active {
    font-size: var(--fs-base);
    color: var(--color-secondary);
}

/* .nav-item.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 1px;
    background: currentColor;
} */

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 22px;
    height: 1.5px;
    background: #fff;
    transition: all 0.3s;
}

.site-header.is-fixed .mobile-menu-btn span {
    background: var(--color-text-dark);
}

/* ========== 右侧功能区 ========== */
.header-right {
    display: flex;
    align-items: center;
    gap: 18px;
}

/* 搜索图标按钮 */
.search-icon-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    cursor: pointer;
    color: rgba(255, 255, 255, 0.85);
    padding: 0;
    transition: color 0.3s;
    line-height: 1;
}

.search-icon-btn:hover {
    color: #fff;
}

.site-header.is-fixed .search-icon-btn {
    color: var(--color-text-body);
}

.site-header.is-fixed .search-icon-btn:hover {
    color: var(--color-seal);
}
/* 语言切换（暂时隐藏，目前仅提供中文版） */
.lang-switch {
    display: none; /* 暂时隐藏，恢复时改回 flex */
    align-items: center;
    gap: 5px;
    font-size: 13px;
    letter-spacing: 0.5px;
    color: rgba(255, 255, 255, 0.85);
}

.lang-item {
    cursor: pointer;
    transition: color 0.3s;
}

.lang-item.active,
.lang-item:hover {
    color: #fff;
}

.lang-sep {
    opacity: 0.4;
    font-size: 11px;
    line-height: 1;
}

.site-header.is-fixed .lang-switch {
    color: var(--color-text-body);
}

.site-header.is-fixed .lang-item.active,
.site-header.is-fixed .lang-item:hover {
    color: var(--color-seal);
}
/* 登录按钮 */
.login-btn {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.85);
    letter-spacing: 1px;
    border: 1px solid rgba(255, 255, 255, 0.45);
    padding: 4px 16px;
    border-radius: var(--radius-full);
    transition: all 0.3s;
    text-decoration: none;
    white-space: nowrap;
}

.login-btn:hover {
    color: #fff;
    border-color: rgba(255, 255, 255, 0.9);
}

.site-header.is-fixed .login-btn {
    color: var(--color-text-main);
    border-color: var(--color-text-muted);
}

.site-header.is-fixed .login-btn:hover {
    color: var(--color-seal);
    border-color: var(--color-seal);
}
/* ========== 响应式：平板及以下 ========== */
@media (max-width: 1199px) {
    :root {
        --header-h: 56px;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: var(--header-h);
        left: 0;
        right: 0;
        background: rgba(248, 245, 242, 0.98);
        flex-direction: column;
        padding: 16px 0;
        gap: 0;
        transform: translateY(-120%);
        opacity: 0;
        transition: all 0.3s ease;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    }

    .nav-menu.is-open {
        transform: translateY(0);
        opacity: 1;
    }

    .nav-item {
        color: var(--color-text-dark);
        padding: 12px 0;
        text-align: center;
        width: 100%;
    }

    /* 折叠菜单（米黄底）上 hover/active 改用印章色，避免白字看不清 */
    .nav-item:hover,
    .nav-item.active {
        color: var(--color-seal);
    }

    .header-right {
        display: none;
    }
}