/* ============================================
   Mega Menu 顶栏导航
   包含：导航项、下拉面板、列布局、交互动效
   ============================================ */

/* ---- 导航容器（桌面居中） ---- */
.mega-nav {
    display: flex;
    align-items: stretch;
    flex: 1;
    justify-content: center;
    gap: 0;
}

/* ---- 直接跳转链接 ---- */
.mega-nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 0 14px;
    height: 64px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    white-space: nowrap;
    position: relative;
    transition: color var(--transition-fast);
    border: none;
    background: none;
    font-family: var(--font-sans);
    cursor: pointer;
}

.mega-nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 14px;
    right: 14px;
    height: 2px;
    background: var(--action-color);
    border-radius: var(--radius-full);
    transform: scaleX(0);
    transition: transform var(--transition-fast);
}

.mega-nav-link:hover {
    color: var(--primary-color);
}

.mega-nav-link.active {
    color: var(--action-color);
    font-weight: 600;
}

.mega-nav-link.active::after,
.mega-nav-link:hover::after {
    transform: scaleX(1);
}

/* ---- 有下拉菜单的项容器 ---- */
.mega-nav-item {
    position: relative;
    display: flex;
    align-items: stretch;
}

/* ---- 下拉触发按钮 ---- */
.mega-nav-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 0 14px;
    height: 64px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    background: none;
    border: none;
    cursor: pointer;
    white-space: nowrap;
    font-family: var(--font-sans);
    position: relative;
    transition: color var(--transition-fast);
}

.mega-nav-btn::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 14px;
    right: 14px;
    height: 2px;
    background: var(--action-color);
    border-radius: var(--radius-full);
    transform: scaleX(0);
    transition: transform var(--transition-fast);
}

.mega-nav-item:hover .mega-nav-btn,
.mega-nav-item.open .mega-nav-btn {
    color: var(--primary-color);
}

.mega-nav-item.active .mega-nav-btn {
    color: var(--action-color);
    font-weight: 600;
}

.mega-nav-item.active .mega-nav-btn::after,
.mega-nav-item.open .mega-nav-btn::after {
    transform: scaleX(1);
}

/* 下拉箭头旋转 */
.mega-arrow {
    font-size: 1rem;
    opacity: 0.55;
    transition: transform var(--transition-fast), opacity var(--transition-fast);
    flex-shrink: 0;
}

.mega-nav-item.open .mega-arrow {
    transform: rotate(180deg);
    opacity: 1;
}

/* ---- 下拉面板（fixed，覆盖全宽） ---- */
.mega-dropdown {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg-card);
    border-top: 2px solid var(--action-color);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-xl);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.16s ease, transform 0.16s ease, visibility 0.16s;
    z-index: 200;
    pointer-events: none;
}

.mega-nav-item.open .mega-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    pointer-events: auto;
}

/* 内容居中约束 */
.mega-dropdown-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-lg);
    display: flex;
    gap: var(--spacing-2xl);
}

/* ---- 列 ---- */
.mega-col {
    flex: 1;
    min-width: 150px;
    max-width: 240px;
}

.mega-col-title {
    font-size: 0.68rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.09em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-xs);
    border-bottom: 1px solid var(--border-light);
}

/* ---- 子菜单项 ---- */
.mega-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 7px var(--spacing-sm);
    border-radius: var(--radius-md);
    font-size: 0.845rem;
    color: var(--text-secondary);
    text-decoration: none;
    transition: background var(--transition-fast), color var(--transition-fast), padding-left var(--transition-fast);
    line-height: 1.4;
}

.mega-item:hover {
    background: var(--action-light);
    color: var(--action-color);
    padding-left: calc(var(--spacing-sm) + 3px);
}

.mega-item.active {
    background: var(--action-light);
    color: var(--action-color);
    font-weight: 500;
}

.mega-item i {
    font-size: 0.95rem;
    width: 18px;
    text-align: center;
    flex-shrink: 0;
    opacity: 0.65;
    transition: opacity var(--transition-fast);
}

.mega-item:hover i,
.mega-item.active i {
    opacity: 1;
}

/* ---- CTA 按钮（升级会员） ---- */
.mega-nav-cta {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    align-self: center;
    margin: 0 0 0 10px;
    padding: 5px 14px;
    font-size: 0.8rem;
    font-weight: 600;
    color: #fff;
    background: var(--accent-color);
    border-radius: var(--radius-full);
    text-decoration: none;
    white-space: nowrap;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(237, 137, 54, 0.30);
    transition: background var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

.mega-nav-cta:hover {
    background: #d97706;
    color: #fff;
    text-decoration: none;
    transform: translateY(-1px);
    box-shadow: 0 4px 14px rgba(237, 137, 54, 0.40);
}

.mega-nav-cta.active {
    background: #b45309;
    color: #fff;
}

.mega-nav-cta i {
    font-size: 0.9rem;
}

/* ---- 响应式：≤1024px 隐藏顶栏 mega nav ---- */
@media (max-width: 1024px) {
    .mega-nav {
        display: none;
    }
}