/* ===== 隐藏滚动条 ===== */
::-webkit-scrollbar { display: none; }
* { scrollbar-width: none; -ms-overflow-style: none; }
body { font-family: "Microsoft YaHei", "PingFang SC", -apple-system, sans-serif; }

/* ===== 顶部导航 ===== */
.site-header {
    background: #fff;
    border-bottom: 1px solid #f0f0f0;
    position: sticky;
    top: 0;
    z-index: 1000;
}
.site-header .container { max-width: 1680px; --bs-gutter-x: 10px; }
.site-header .navbar { padding-top: 0; padding-bottom: 0; }
.site-header .navbar-collapse { flex-grow: 0; margin-left: auto; }
.site-header .navbar-brand { padding: 10px 0; display: flex; align-items: center; }
.site-header .navbar-brand .logo-text { font-size: 30px; font-weight: 700; color: #1a3a5c; line-height: 1.2; }
.site-header .navbar-brand .logo-sub { font-size: 15px; color: #999; letter-spacing: 2px; }
.site-header .navbar-nav .nav-link {
    padding: 22px 16px;
    font-size: 22px;
    color: #333;
    font-weight: 500;
    position: relative;
    transition: color 0.3s;
    margin: 0 15px;
    white-space: nowrap;
}
.site-header .navbar-nav .nav-link:hover,
.site-header .navbar-nav .nav-link.active { color: #0d6efd; }
.site-header .navbar-nav .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0; left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 60%; height: 3px;
    background: #0d6efd;
    transition: transform 0.3s;
    border-radius: 2px 2px 0 0;
}
.site-header .navbar-nav .nav-link:hover::after,
.site-header .navbar-nav .nav-link.active::after {
    transform: translateX(-50%) scaleX(1);
}
.site-header .dropdown-menu {
    border: none;
    border-radius: 0 0 8px 8px;
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
    padding: 8px 0;
    margin-top: 0;
    min-width: 180px;
}
.site-header .dropdown-menu .dropdown-item {
    padding: 10px 22px;
    font-size: 20px;
    color: #555;
    transition: all 0.2s;
}
.site-header .dropdown-menu .dropdown-item:hover {
    background: #f0f7ff;
    color: #0d6efd;
}
.site-header .nav-extra {
    display: flex; align-items: center; gap: 16px; margin-left: 20px;
}
.site-header .nav-extra .lang-switch { font-size: 16px; color: #999; visibility: hidden; /* 隐藏文字，保留占位 */ }
.site-header .nav-extra .lang-switch a { color: #666; text-decoration: none; padding: 0 4px; }
.site-header .nav-extra .lang-switch a:hover,
.site-header .nav-extra .lang-switch a.active { color: #0d6efd; }
.site-header .nav-extra .lang-switch .sep { color: #ddd; }
.site-header .nav-extra .search-icon {
    font-size: 24px; color: #666; cursor: pointer;
    background: none; border: none; padding: 0;
}
.site-header .nav-extra .search-icon:hover { color: #0d6efd; }

/* ===== 导航下拉菜单：悬停触发 ===== */
@media (min-width: 992px) {
    .nav-item.dropdown:hover .dropdown-menu {
        display: block;
    }
    .nav-item.dropdown .dropdown-menu {
        margin-top: 0;
    }
}

/* ===== 页脚 ===== */
.site-footer { background: #1a1a2e; color: #fff; padding: 60px 0 30px; }
.site-footer a { color: rgba(255,255,255,0.6); text-decoration: none; transition: color 0.2s; }
.site-footer a:hover { color: #fff; }
.footer-link { color: rgba(255,255,255,0.6); text-decoration: none; }
.footer-link:hover { color: #fff; }

/* ===== 搜索覆盖层 ===== */
.search-overlay {
    position: fixed; top: 0; left: 0;
    width: 100%; height: 100%;
    background: rgba(0,0,0,0.65);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 9999;
    display: flex; align-items: center; justify-content: center;
    opacity: 0; visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}
.search-overlay.active { opacity: 1; visibility: visible; }
.search-overlay-content {
    width: 100%; max-width: 680px; padding: 0 24px;
    position: relative;
    transform: translateY(-30px);
    transition: transform 0.35s ease;
}
.search-overlay.active .search-overlay-content { transform: translateY(0); }
.search-overlay-close {
    position: absolute; top: -70px; right: 24px;
    background: none; border: 2px solid rgba(255,255,255,0.25);
    color: #fff; width: 46px; height: 46px;
    border-radius: 50%; font-size: 18px;
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: all 0.2s;
}
.search-overlay-close:hover { border-color: rgba(255,255,255,0.6); background: rgba(255,255,255,0.1); }
.search-overlay-form { width: 100%; }
.search-overlay-input-group {
    display: flex; align-items: center;
    background: #fff; border-radius: 50px;
    padding: 6px 6px 6px 24px;
    box-shadow: 0 8px 40px rgba(0,0,0,0.18);
}
.search-overlay-icon { font-size: 22px; color: #bbb; margin-right: 12px; }
.search-overlay-input {
    flex: 1; border: none; outline: none; font-size: 18px;
    padding: 14px 0; background: transparent; color: #333;
}
.search-overlay-input::placeholder { color: #bbb; }
.search-overlay-submit {
    background: #0d6efd; color: #fff; border: none;
    border-radius: 50px; padding: 12px 32px;
    font-size: 16px; font-weight: 600; cursor: pointer;
    transition: background 0.2s; white-space: nowrap;
}
.search-overlay-submit:hover { background: #0b5ed7; }