/* ============================================
   CSS 样式文件 - 左右分栏 + 大留白布局
   包含：毛玻璃效果、微交互动效、大号粗体标题
   ============================================ */

/* ============================================
   1. CSS 变量定义
   ============================================ */
:root {
    /* 主色调 */
    --primary-color: #6366f1;
    --primary-light: #818cf8;
    --primary-dark: #4f46e5;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #ec4899 100%);
    --gradient-bg: linear-gradient(180deg, #0f0f23 0%, #1a1a2e 50%, #16213e 100%);
    --gradient-text: linear-gradient(135deg, #ffffff 0%, #a5b4fc 50%, #f0abfc 100%);
    
    /* 毛玻璃效果 */
    --glass-bg: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.15);
    --glass-shadow: rgba(0, 0, 0, 0.3);
    
    /* 文字颜色 */
    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    
    /* 间距系统 */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-xxl: 5rem;
    
    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    
    /* 过渡 */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* 阴影 */
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.3);
}

/* ============================================
   2. 全局重置与基础样式
   ============================================ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--gradient-bg);
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.05);
}

::-webkit-scrollbar-thumb {
    background: var(--glass-border);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* 选中样式 */
::selection {
    background: var(--primary-color);
    color: white;
}

/* ============================================
   3. 排版
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    letter-spacing: -0.02em;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    letter-spacing: -0.01em;
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
    font-size: 1.25rem;
}

p {
    color: var(--text-secondary);
    max-width: 65ch;
}

a {
    color: var(--primary-light);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-color);
}

/* ============================================
   4. 主容器布局
   ============================================ */
.container {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* 左右分栏布局 */
.main-layout {
    display: flex;
    min-height: 100vh;
    gap: var(--space-xxl);
}

/* 左侧边栏 */
.sidebar {
    flex: 0 0 320px;
    position: sticky;
    top: 0;
    height: 100vh;
    padding: var(--space-xl) 0;
    display: flex;
    flex-direction: column;
}

/* 右侧主内容区 */
.main-content {
    flex: 1;
    padding: var(--space-xl) 0;
    padding-right: var(--space-xl);
}

/* 大留白区域 */
.section-spacing {
    padding: var(--space-xxl) 0;
}

/* ============================================
   5. 导航栏
   ============================================ */
.navbar {
    margin-bottom: var(--space-xxl);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-xl);
    padding: var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--transition-normal);
}

.nav-brand:hover {
    transform: translateX(8px);
    box-shadow: var(--shadow-glow);
}

.nav-brand-logo {
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.25rem;
}

.nav-brand-text {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.nav-item {
    position: relative;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
    background: var(--glass-bg);
}

.nav-link.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 24px;
    background: var(--gradient-primary);
    border-radius: 0 2px 2px 0;
}

.nav-link svg {
    width: 20px;
    height: 20px;
    opacity: 0.7;
    transition: opacity var(--transition-fast);
}

.nav-link:hover svg,
.nav-link.active svg {
    opacity: 1;
}

/* ============================================
   6. 头部区域
   ============================================ */
.header {
    margin-bottom: var(--space-xxl);
}

.header-content {
    max-width: 600px;
}

.header-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
    font-size: 0.875rem;
    color: var(--primary-light);
    margin-bottom: var(--space-md);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.header-title {
    margin-bottom: var(--space-md);
}

.header-description {
    font-size: 1.125rem;
    margin-bottom: var(--space-lg);
    line-height: 1.8;
}

/* ============================================
   7. 按钮样式
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: 0.875rem 1.75rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s ease;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(99, 102, 241, 0.5);
}

.btn-secondary {
    background: var(--glass-bg);
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-2px);
}

.btn-icon {
    width: 44px;
    height: 44px;
    padding: 0;
    border-radius: var(--radius-md);
}

.btn-group {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

/* ============================================
   8. 卡片样式
   ============================================ */
.card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border-color: rgba(255, 255, 255, 0.25);
}

.card-elevated {
    box-shadow: var(--shadow-md);
}

.card-elevated:hover {
    box-shadow: var(--shadow-lg);
}

.card-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: var(--radius-md);
    margin-bottom: var(--space-md);
}

.card-header {
    margin-bottom: var(--space-md);
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: var(--space-xs);
}

.card-subtitle {
    color: var(--text-muted);
    font-size: 0.875rem;
}

.card-body {
    margin-bottom: var(--space-md);
}

.card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-md);
    border-top: 1px solid var(--glass-border);
}

/* 特色卡片 */
.featured-card {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.2) 0%, rgba(236, 72, 153, 0.2) 100%);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

/* 卡片网格 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-lg);
}

.card-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

/* ============================================
   9. 表单样式
   ============================================ */
.form-group {
    margin-bottom: var(--space-md);
}

.form-label {
    display: block;
    margin-bottom: var(--space-xs);
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.form-input {
    width: 100%;
    padding: 0.875rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.form-input::placeholder {
    color: var(--text-muted);
}

.form-input:hover {
    border-color: rgba(255, 255, 255, 0.3);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-input-group {
    display: flex;
    gap: var(--space-xs);
}

.form-input-group .form-input {
    flex: 1;
}

/* 输入框状态 */
.form-input:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.form-input.error {
    border-color: #ef4444;
}

.form-input.success {
    border-color: #22c55e;
}

/* ============================================
   10. 标签与徽章
   ============================================ */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 50px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-primary {
    background: rgba(99, 102, 241, 0.2);
    color: var(--primary-light);
}

.badge-success {
    background: rgba(34, 197, 94, 0.2);
    color: #4ade80;
}

.badge-warning {
    background: rgba(251, 191, 36, 0.2);
    color: #fbbf24;
}

.badge-danger {
    background: rgba(239, 68, 68, 0.2);
    color: #f87171;
}

/* 标签列表 */
.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
}

.tag {
    padding: 0.375rem 0.875rem;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.tag:hover {
    background: rgba(99, 102, 241, 0.2);
    border-color: var(--primary-color);
    color: var(--primary-light);
}

/* ============================================
   11. 列表样式
   ============================================ */
.list {
    list-style: none;
}

.list-item {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) 0;
    border-bottom: 1px solid var(--glass-border);
    transition: all var(--transition-fast);
}

.list-item:last-child {
    border-bottom: none;
}

.list-item:hover {
    padding-left: var(--space-sm);
}

.list-icon {
    width: 40px;
    height: 40px;
    background: var(--glass-bg);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.list-content {
    flex: 1;
}

.list-title {
    font-weight: 600;
    margin-bottom: 2px;
}

.list-description {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* ============================================
   12. 统计组件
   ============================================ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.stat-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    text-align: center;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--transition-normal);
}

.stat-card:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-glow);
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: var(--space-xs);
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.875rem;
}

.stat-change {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 0.75rem;
    margin-top: var(--space-xs);
    padding: 2px 8px;
    border-radius: 50px;
}

.stat-change.positive {
    background: rgba(34, 197, 94, 0.2);
    color: #4ade80;
}

.stat-change.negative {
    background: rgba(239, 68, 68, 0.2);
    color: #f87171;
}

/* ============================================
   13. 分隔线与装饰
   ============================================ */
.divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--glass-border), transparent);
    margin: var(--space-xl) 0;
}

.divider-vertical {
    width: 1px;
    background: linear-gradient(180deg, transparent, var(--glass-border), transparent);
    margin: 0 var(--space-lg);
}

/* 几何装饰 */
.decorative-circle {
    position: absolute;
    border-radius: 50%;
    background: var(--gradient-primary);
    opacity: 0.1;
    filter: blur(60px);
    pointer-events: none;
}

.decorative-circle-1 {
    width: 300px;
    height: 300px;
    top: -100px;
    right: -100px;
}

.decorative-circle-2 {
    width: 200px;
    height: 200px;
    bottom: 20%;
    left: -50px;
}

/* 装饰线条 */
.decorative-line {
    position: absolute;
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
    height: 1px;
    width: 100px;
}

/* ============================================
   14. 区块组件
   ============================================ */
.section {
    padding: var(--space-xxl) 0;
}

.section-header {
    margin-bottom: var(--space-xl);
}

.section-title {
    margin-bottom: var(--space-sm);
}

.section-description {
    max-width: 600px;
}

/* 特色区块 */
.feature-block {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    padding: var(--space-xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    transition: all var(--transition-normal);
}

.feature-block:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-glow);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.feature-icon svg {
    width: 40px;
    height: 40px;
    color: white;
}

.feature-content {
    flex: 1;
}

.feature-title {
    margin-bottom: var(--space-xs);
}

.feature-description {
    margin-bottom: 0;
}

/* ============================================
   15. 模态框与弹窗（毛玻璃效果）
   ============================================ */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: rgba(26, 26, 46, 0.95);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow: auto;
    backdrop-filter: blur(40px);
    -webkit-backdrop-filter: blur(40px);
    transform: scale(0.9);
    transition: transform var(--transition-normal);
}

.modal-overlay.active .modal {
    transform: scale(1);
}

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

.modal-title {
    font-size: 1.25rem;
}

.modal-close {
    width: 36px;
    height: 36px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: rgba(239, 68, 68, 0.2);
    border-color: #ef4444;
    color: #f87171;
}

.modal-body {
    padding: var(--space-lg);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-sm);
    padding: var(--space-lg);
    border-top: 1px solid var(--glass-border);
}

/* ============================================
   16. 进度条与加载
   ============================================ */
.progress {
    height: 8px;
    background: var(--glass-bg);
    border-radius: 50px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 50px;
    transition: width var(--transition-slow);
}

.progress-label {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--space-xs);
    font-size: 0.875rem;
}

/* 骨架屏 */
.skeleton {
    background: linear-gradient(90deg, var(--glass-bg) 25%, rgba(255,255,255,0.1) 50%, var(--glass-bg) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: var(--radius-sm);
}

@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

.skeleton-text {
    height: 1em;
    margin-bottom: 0.5em;
}

.skeleton-title {
    height: 1.5em;
    width: 60%;
    margin-bottom: 0.5em;
}

.skeleton-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
}

/* 加载动画 */
.spinner {
    width: 24px;
    height: 24px;
    border: 2px solid var(--glass-border);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ============================================
   17. 工具类
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--primary-light); }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }

.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.font-medium { font-weight: 500; }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }

.grid { display: grid; }
.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); }

.w-full { width: 100%; }
.h-full { height: 100%; }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

.p-sm { padding: var(--space-sm); }
.p-md { padding: var(--space-md); }
.p-lg { padding: var(--space-lg); }
.p-xl { padding: var(--space-xl); }

.rounded { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-full { border-radius: 50%; }

.shadow { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }

.hidden { display: none; }
.visible { visibility: visible; }
.invisible { visibility: hidden; }

.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }

.relative { position: relative; }
.absolute { position: absolute; }
.fixed { position: fixed; }
.sticky { position: sticky; }

.top-0 { top: 0; }
.left-0 { left: 0; }
.right-0 { right: 0; }
.bottom-0 { bottom: 0; }

/* 渐变文字 */
.gradient-text {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 毛玻璃背景 */
.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
}

/* ============================================
   18. 响应式设计
   ============================================ */
@media screen and (max-width: 1200px) {
    .sidebar {
        flex: 0 0 280px;
    }
    
    .container {
        padding: 0 var(--space-md);
    }
}

@media screen and (max-width: 992px) {
    .main-layout {
        flex-direction: column;
        gap: var(--space-lg);
    }
    
    .sidebar {
        position: relative;
        flex: none;
        height: auto;
        padding: var(--space-md) 0;
    }
    
    .nav-menu {
        flex-direction: row;
        overflow-x: auto;
        gap: var(--space-xs);
        padding-bottom: var(--space-sm);
    }
    
    .nav-link {
        white-space: nowrap;
    }
    
    .nav-link.active::before {
        display: none;
    }
    
    .main-content {
        padding-right: 0;
    }
    
    .card-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    }
    
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .feature-block {
        flex-direction: column;
        text-align: center;
    }
}

@media screen and (max-width: 768px) {
    :root {
        --space-xl: 2rem;
        --space-xxl: 3rem;
    }
    
    h1 {
        font-size: 2.5rem;
    }
    
    h2 {
        font-size: 1.75rem;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .card-grid {
        grid-template-columns: 1fr;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .form-input-group {
        flex-direction: column;
    }
    
    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: 1fr;
    }
}

@media screen and (max-width: 480px) {
    :root {
        --space-lg: 1.5rem;
        --space-xl: 2rem;
        --space-xxl: 2.5rem;
    }
    
    .container {
        padding: 0 var(--space-sm);
    }
    
    .card {
        padding: var(--space-md);
    }
    
    .stat-value {
        font-size: 2rem;
    }
    
    .feature-icon {
        width: 60px;
        height: 60px;
    }
    
    .feature-icon svg {
        width: 30px;
        height: 30px;
    }
}

/* ============================================
   19. 动画与过渡效果
   ============================================ */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-20px);
    }
}

@keyframes glow {
    0%, 100% {
        box-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
    }
    50% {
        box-shadow: 0 0 40px rgba(99, 102, 241, 0.6);
    }
}

/* 动画类 */
.animate-fadeIn {
    animation: fadeIn 0.6s ease forwards;
}

.animate-slideInLeft {
    animation: slideInLeft 0.6s ease forwards;
}

.animate-slideInRight {
    animation: slideInRight 0.6s ease forwards;
}

.animate-pulse {
    animation: pulse 2s ease-in-out infinite;
}

.animate-bounce {
    animation: bounce 1s ease infinite;
}

.animate-float {
    animation: float 3s ease-in-out infinite;
}

.animate-glow {
    animation: glow 2s ease-in-out infinite;
}

/* 延迟类 */
.delay-100 { animation-delay: 0.1s; }
.delay-200 { animation-delay: 0.2s; }
.delay-300 { animation-delay: 0.3s; }
.delay-400 { animation-delay: 0.4s; }
.delay-500 { animation-delay: 0.5s; }

/* 悬停缩放 */
.hover-scale {
    transition: transform var(--transition-normal);
}

.hover-scale:hover {
    transform: scale(1.05);
}

/* 悬停提升 */
.hover-lift {
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.hover-lift:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* ============================================
   20. 打印样式
   ============================================ */
@media print {
    body {
        background: white;
        color: black;
    }
    
    .sidebar,
    .modal-overlay,
    .decorative-circle,
    .btn {
        display: none !important;
    }
    
    .card {
        background: white;
        border: 1px solid #ddd;
        box-shadow: none;
    }
    
    h1, h2, h3 {
        color: black;
        background: none;
        -webkit-text-fill-color: black;
    }
}
```