/* ========================================
   TYILRN - Modern Educational Layout
   包含：网格、布局容器、导航、页脚、响应式、丰富动画
   ======================================== */

/* 容器 */
.container {
    width: 100%;
    max-width: 1280px;
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--space-4);
    padding-right: var(--space-4);
}

.container-sm {
    max-width: 640px;
}

.container-md {
    max-width: 768px;
}

.container-lg {
    max-width: 1024px;
}

.container-xl {
    max-width: 1280px;
}

/* 页面布局 */
.page-layout {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.page-main {
    flex: 1;
    padding-top: var(--space-6);
    padding-bottom: var(--space-10);
}

/* 侧边栏布局 */
.layout-with-sidebar {
    display: flex;
    gap: var(--space-6);
}

.layout-sidebar {
    width: 240px;
    flex-shrink: 0;
}

.layout-content {
    flex: 1;
    min-width: 0;
}

/* 网格系统 */
.grid {
    display: grid;
    gap: var(--space-4);
}

.grid-cols-1 { grid-template-columns: repeat(1, 1fr); }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }
.grid-cols-5 { grid-template-columns: repeat(5, 1fr); }
.grid-cols-6 { grid-template-columns: repeat(6, 1fr); }

/* ===== 导航栏 —— 强液态玻璃 ===== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    height: 64px;
    background: var(--glass-bg-solid);
    backdrop-filter: var(--glass-blur-heavy);
    -webkit-backdrop-filter: var(--glass-blur-heavy);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: var(--glass-highlight);
    transition: background var(--transition-slow), border-color var(--transition-slow);
}

.navbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    gap: var(--space-2);
}
.navbar-brand {
    flex-shrink: 0;
}
.navbar-actions {
    flex-shrink: 0;
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
    transition: transform var(--transition-fast);
}

.navbar-brand:hover {
    opacity: 1;
    transform: scale(1.02);
}

.navbar-brand-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, rgba(37,99,235,0.85), rgba(59,130,246,0.85));
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 16px;
    border: 1px solid rgba(255,255,255,0.30);
    box-shadow: inset 0 1px 0 rgba(255,255,255,0.35);
    transition: transform var(--transition-bounce);
}

.navbar-brand:hover .navbar-brand-icon {
    transform: rotate(-5deg) scale(1.08);
}

.navbar-nav {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    flex: 1;
    justify-content: center;
    margin: 0 var(--space-2);
    padding: 0 var(--space-1);
    white-space: nowrap;
}
.navbar-nav.desktop-nav {
    position: static;
    flex-direction: row;
    overflow: visible;
}
.navbar-nav .nav-dropdown {
    position: relative;
}
.mobile-nav {
    display: none;
    position: fixed;
    top: 0;
    right: 0;
    width: 280px;
    max-width: 85vw;
    height: 100vh;
    height: 100dvh;
    background: var(--glass-bg-solid);
    backdrop-filter: var(--glass-blur-heavy);
    -webkit-backdrop-filter: var(--glass-blur-heavy);
    border-left: 1px solid var(--glass-border);
    z-index: 100;
    overflow-y: auto;
    overflow-x: hidden;
    transform: translateX(100%);
    transition: transform 0.3s ease;
}
.mobile-nav.open {
    transform: translateX(0);
}
.mobile-nav-inner {
    padding: 72px 16px 24px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.mobile-nav-group {
    display: flex;
    flex-direction: column;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
}
.mobile-nav-group:last-child {
    border-bottom: none;
}
.mobile-nav-title {
    padding: 6px 12px;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}
.mobile-nav .nav-link {
    padding: 10px 12px;
    font-size: 14px;
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
}
.mobile-nav .nav-link:hover,
.mobile-nav .nav-link.active {
    background: rgba(37, 99, 235, 0.08);
    color: var(--primary);
}

.nav-link {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--primary);
    opacity: 0;
    transform: scale(0.8);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
    z-index: -1;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
    background: rgba(37, 99, 235, 0.08);
}

.nav-link:hover::before,
.nav-link.active::before {
    opacity: 0.06;
    transform: scale(1);
}

.nav-link.active {
    font-weight: 600;
}

.navbar-actions {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

/* 移动端菜单 —— 玻璃面板 */
.mobile-menu-btn {
    display: none;
    padding: var(--space-2);
    color: var(--text-secondary);
    background: rgba(255, 255, 255, 0.30);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--glass-border);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    z-index: 10;
    overflow: hidden;
}

.mobile-menu-btn:hover {
    background: rgba(255, 255, 255, 0.50);
    transform: scale(1.05);
}

.mobile-menu-btn:active {
    transform: scale(0.95);
}

.mobile-menu-btn.active {
    background: rgba(37, 99, 235, 0.15);
    color: var(--primary);
    border-color: rgba(37, 99, 235, 0.25);
}

.mobile-nav-section {
    display: none;
}

.mobile-menu-overlay {
    display: none;
}

/* ===== 页脚 —— 深色液态玻璃 ===== */
.footer {
    background: rgba(15, 23, 42, 0.80);
    backdrop-filter: var(--glass-blur-heavy);
    color: var(--gray-400);
    padding: var(--space-10) 0 var(--space-6);
    border-top: 1px solid rgba(255,255,255,0.08);
}

.footer-inner {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--space-8);
}

.footer-brand {
    color: white;
    font-size: 18px;
    font-weight: 700;
    margin-bottom: var(--space-4);
}

.footer-desc {
    font-size: 13px;
    line-height: 1.7;
    margin-bottom: var(--space-4);
}

.footer-title {
    color: white;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: var(--space-4);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.footer-links a {
    color: var(--gray-400);
    font-size: 13px;
    transition: all var(--transition-fast);
    position: relative;
    display: inline-block;
}

.footer-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: white;
    transition: width var(--transition-fast);
}

.footer-links a:hover {
    color: white;
    opacity: 1;
}

.footer-links a:hover::after {
    width: 100%;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.08);
    margin-top: var(--space-8);
    padding-top: var(--space-6);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
}

/* 卡片网格 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-4);
}

/* 内容区 —— 液态玻璃 */
.content-section {
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-highlight);
    overflow: hidden;
    transition: all var(--transition-fast);
}

.content-section:hover {
    background: var(--glass-bg-hover);
    border-color: var(--glass-border-strong);
    transform: scale(1.002);
}

.content-section-header {
    padding: var(--space-4) var(--space-6);
    border-bottom: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.content-section-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.content-section-body {
    padding: var(--space-6);
}

/* 两栏布局 */
.two-column {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: var(--space-6);
}

/* 三栏布局 */
.three-column {
    display: grid;
    grid-template-columns: 240px 1fr 280px;
    gap: var(--space-6);
}

/* 侧边栏导航 —— 液态玻璃 */
.sidebar-nav {
    position: sticky;
    top: 80px;
}

.sidebar-menu {
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-highlight);
    overflow: hidden;
    transition: all var(--transition-fast);
}

.sidebar-menu:hover {
    background: var(--glass-bg-hover);
    border-color: var(--glass-border-strong);
}

.sidebar-menu-title {
    padding: var(--space-4) var(--space-5);
    font-size: 12px;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.sidebar-menu-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-5);
    color: var(--text-secondary);
    font-size: 14px;
    transition: all var(--transition-fast);
    border-left: 3px solid transparent;
    position: relative;
}

.sidebar-menu-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%) scaleY(0);
    width: 3px;
    height: 60%;
    background: var(--primary);
    border-radius: 0 2px 2px 0;
    transition: transform var(--transition-fast);
}

.sidebar-menu-item:hover {
    background: rgba(255, 255, 255, 0.20);
    color: var(--text-secondary);
    padding-left: calc(var(--space-5) + 4px);
}

.sidebar-menu-item.active {
    background: rgba(37, 99, 235, 0.08);
    color: var(--primary);
    font-weight: 500;
}

.sidebar-menu-item.active::before {
    transform: translateY(-50%) scaleY(1);
}

.sidebar-menu-icon {
    width: 20px;
    height: 20px;
    opacity: 0.7;
    transition: all var(--transition-fast);
}

.sidebar-menu-item:hover .sidebar-menu-icon {
    transform: scale(1.15);
}

.sidebar-menu-item.active .sidebar-menu-icon {
    opacity: 1;
    transform: scale(1.1);
}

/* 响应式断点 */
@media (max-width: 1024px) {
    .layout-with-sidebar {
        flex-direction: column;
    }
    .layout-sidebar {
        width: 100%;
    }
    .two-column {
        grid-template-columns: 1fr;
    }
    .three-column {
        grid-template-columns: 1fr;
    }
    .footer-inner {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 1024px) {
    .navbar-nav.desktop-nav {
        display: none;
    }
    .mobile-nav {
        display: block;
    }
    .mobile-menu-btn {
        display: flex;
        align-items: center;
        justify-content: center;
    }
    .hidden-md { display: none !important; }
}

@media (max-width: 768px) {
    .navbar {
        height: 56px;
    }
    .navbar-actions {
        gap: var(--space-2);
    }
    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4,
    .grid-cols-5,
    .grid-cols-6 {
        grid-template-columns: 1fr;
    }
    .footer-inner {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
    .footer-bottom {
        flex-direction: column;
        gap: var(--space-2);
        text-align: center;
    }
    .card-grid {
        grid-template-columns: 1fr;
    }
    .layout-with-sidebar {
        gap: var(--space-4);
    }
    .layout-sidebar {
        order: -1;
    }
    .sidebar-nav {
        position: static;
    }
    .two-column,
    .three-column {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    .mobile-menu-overlay {
        display: none;
        position: fixed;
        inset: 0;
        background: rgba(0,0,0,0.35);
        z-index: 98;
        backdrop-filter: blur(2px);
    }
    .mobile-menu-overlay.active {
        display: block;
    }
    .mobile-nav-section {
        display: flex;
        flex-direction: column;
        gap: var(--space-3);
        margin-top: var(--space-2);
        padding-top: var(--space-2);
        border-top: 1px solid var(--glass-border);
    }
    .mobile-nav-group {
        display: flex;
        flex-direction: column;
    }
    .mobile-nav-title {
        padding: var(--space-2) var(--space-3);
        font-size: 12px;
        font-weight: 600;
        color: var(--text-tertiary);
        text-transform: uppercase;
        letter-spacing: 0.5px;
    }
}

@media (max-width: 480px) {
    .container {
        padding-left: var(--space-3);
        padding-right: var(--space-3);
    }
    .content-section-header,
    .content-section-body {
        padding: var(--space-4);
    }
    .navbar-brand span {
        font-size: 16px;
    }
    .navbar-brand svg {
        width: 28px;
        height: 28px;
    }
    .page-main {
        padding-top: var(--space-4);
        padding-bottom: var(--space-6);
    }
}

/* ===== 响应式网格类 ===== */
.responsive-grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
}

.responsive-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-4);
}

.responsive-grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-4);
}

@media (max-width: 1024px) {
    .responsive-grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
    .responsive-grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .responsive-grid-2,
    .responsive-grid-3,
    .responsive-grid-4 {
        grid-template-columns: 1fr;
    }
}

/* 移动端堆叠的 flex 行 */
.responsive-flex-row {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: var(--space-4);
}

@media (max-width: 768px) {
    .responsive-flex-row {
        flex-direction: column;
        align-items: stretch;
        gap: var(--space-3);
    }
}

/* 响应式页面标题栏 */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-6);
    gap: var(--space-4);
    flex-wrap: wrap;
    animation: fadeIn 0.4s ease;
}

@media (max-width: 768px) {
    .page-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* ===== 页面过渡区域 ===== */
.page-entrance {
    animation: scaleIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.card-entrance {
    opacity: 0;
    animation: scaleIn 0.4s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}