/* ============================================================
   全局布局 (导航栏、下拉抽屉、页脚、Section结构)
============================================================ */

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* --- 顶部导航栏 --- */
.nav-bar {
    position: fixed;
    top: 0; left: 0; right: 0;
    height: var(--nav-height);
    background: rgba(248, 249, 251, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    z-index: 1000;
    border-bottom: 1px solid transparent;
    transition: all var(--transition-fast);
}
.nav-bar.scrolled {
    border-bottom-color: var(--color-border);
    box-shadow: 0 1px 20px rgba(30, 40, 60, 0.05);
}
.nav-inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.nav-logo {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: 8px;
}
.nav-logo .dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--color-accent-gradient);
}
.nav-links {
    display: flex;
    align-items: center;
    gap: 4px;
}
.nav-links > li {
    position: relative; /* 用于定位下拉抽屉 */
}
.nav-links > li > a {
    display: block;
    padding: 8px 16px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    border-radius: var(--border-radius-pill);
}
.nav-links > li > a:hover,
.nav-links > li > a.active {
    color: var(--color-accent);
    background: var(--color-accent-light);
}
.nav-links > li > a.active {
    font-weight: 600;
}

/* 导航栏右侧功能区 */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}
.btn-admin-icon {
    width: 36px; height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    border: 1px solid transparent;
    transition: all var(--transition-fast);
    position: relative;
}
.btn-admin-icon:hover {
    border-color: var(--color-accent);
}

/* 汉堡菜单 (移动端) */
.nav-hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    z-index: 1001;
}
.nav-hamburger span {
    width: 24px; height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all var(--transition-fast);
}
.nav-hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.active span:nth-child(2) { opacity: 0; }
.nav-hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- 作品展示下拉抽屉 (桌面端) --- */
.nav-links > li {
    position: relative; /* 用于定位下拉抽屉 */
}
/* 为了防止鼠标在导航栏和抽屉之间移动时触发 mouseleave，我们需要一个透明的桥梁 (bridge) */
.nav-links > li.has-dropdown::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    height: 12px; /* 增加一个无形的悬停区 */
    background: transparent;
    display: none;
}
.nav-links > li.has-dropdown:hover::after {
    display: block;
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 10px); /* 留出空间给 bridge */
    left: 50%;
    transform: translateX(-50%) translateY(-8px);
    width: 220px;
    background: var(--color-card);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-dropdown);
    padding: 8px;
    opacity: 0;
    pointer-events: none;
    transition: all 0.2s ease-out;
}
/* 鼠标悬停父级li时展开 */
.nav-links > li.has-dropdown:hover .dropdown-menu {
    opacity: 1;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}
.dropdown-menu li a {
    display: block;
    padding: 10px 16px;
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
}
.dropdown-menu li a:hover {
    background: var(--color-accent-light);
    color: var(--color-accent);
}

/* --- ⚙️ 已登录状态管理抽屉 --- */
.admin-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    width: 200px;
    background: var(--color-card);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-dropdown);
    padding: 12px;
    opacity: 0;
    pointer-events: none;
    transform: translateY(-10px);
    transition: all 0.2s ease-out;
}
.admin-dropdown.active {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}
.admin-dropdown .btn-primary,
.admin-dropdown .btn-secondary {
    width: 100%;
    margin-bottom: 8px;
}
.admin-dropdown .btn-secondary {
    margin-bottom: 0;
}

/* --- Section 通用 --- */
.section {
    padding: var(--section-padding);
}
.section-header {
    text-align: center;
    margin-bottom: 56px;
}
.section-label {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--color-accent);
    margin-bottom: 8px;
}
.section-title {
    font-size: clamp(1.6rem, 3vw, 2rem);
    font-weight: 700;
    color: var(--color-text);
    letter-spacing: -0.4px;
    margin-bottom: 12px;
}
.section-desc {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* --- 页脚 --- */
.site-footer {
    background: var(--color-surface-dark);
    color: var(--color-footer-text);
    padding: 50px 28px 36px;
    text-align: center;
}
.footer-inner {
    max-width: 600px;
    margin: 0 auto;
}
.footer-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 24px;
}
.footer-contact {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 24px;
    font-size: 0.9rem;
}
.footer-contact span {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.footer-divider {
    width: 50px;
    height: 1px;
    background: rgba(255,255,255,0.2);
    margin: 24px auto;
}
.footer-copy {
    font-size: 0.78rem;
    color: var(--color-text-light);
}
.footer-icp {
    margin-top: 12px;
}
.footer-icp a {
    font-size: 0.78rem;
    color: var(--color-text-light);
    text-decoration: none;
    transition: color var(--transition-fast);
}
.footer-icp a:hover {
    color: var(--color-accent);
}

/* --- 返回顶部按钮 --- */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 44px; height: 44px;
    border-radius: 50%;
    background: var(--color-card);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 999;
    opacity: 0;
    pointer-events: none;
    transform: translateY(16px);
    transition: all var(--transition-fast);
}
.back-to-top.visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}
.back-to-top:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-3px);
}

/* ============================================================
   移动端响应式 (导航栏特化)
============================================================ */
@media (max-width: 768px) {
    .nav-hamburger {
        display: flex;
    }
    /* 汉堡菜单展开后的侧边栏 */
    .nav-links {
        position: fixed;
        top: 0; right: -260px;
        width: 260px; height: 100vh;
        background: var(--color-card);
        flex-direction: column;
        align-items: flex-start;
        padding: 80px 24px 40px;
        box-shadow: -4px 0 30px rgba(0,0,0,0.08);
        transition: right var(--transition-smooth);
    }
    .nav-links.open {
        right: 0;
    }
    .nav-links > li {
        width: 100%;
    }
    .nav-links > li > a {
        padding: 12px 16px;
        font-size: 1rem;
    }
    
    /* 移动端手风琴菜单 */
    .nav-links > li.has-dropdown > a {
        display: flex;
        justify-content: space-between;
        align-items: center;
    }
    .nav-links > li.has-dropdown > a::after {
        content: '▼';
        font-size: 0.7rem;
        transition: transform 0.2s;
    }
    .nav-links > li.has-dropdown.open > a::after {
        transform: rotate(180deg);
    }
    .dropdown-menu {
        position: static;
        width: 100%;
        transform: none;
        box-shadow: none;
        background: var(--color-bg);
        margin-top: 4px;
        display: none; /* 初始隐藏 */
        opacity: 1;
        pointer-events: auto;
    }
    .nav-links > li.has-dropdown.open .dropdown-menu {
        display: block; /* 展开显示 */
    }
}