/* ========================================
   完整CSS样式文件 - 瀑布流卡片设计系统
   包含：毛玻璃效果、渐变背景、微交互动效
   ======================================== */

/* ========================================
   1. CSS变量定义（设计系统）
   ======================================== */
:root {
    /* 主色调 */
    --primary-100: #eef2ff;
    --primary-200: #e0e7ff;
    --primary-300: #c7d2fe;
    --primary-400: #a5b4fc;
    --primary-500: #818cf8;
    --primary-600: #6366f1;
    --primary-700: #4f46e5;
    --primary-800: #4338ca;
    --primary-900: #3730a3;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-dark: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    --gradient-text: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    
    /* 毛玻璃效果 */
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-bg-strong: rgba(255, 255, 255, 0.2);
    --glass-border: rgba(255, 255, 255, 0.2);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    
    /* 中性色 */
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* 阴影 */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.4);
    --shadow-glow-accent: 0 0 30px rgba(118, 75, 162, 0.5);
    
    /* 圆角 */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-2xl: 24px;
    --radius-full: 9999px;
    
    /* 间距 */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    
    /* 字体 */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-display: 'Poppins', var(--font-sans);
    
    /* 过渡 */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
    --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
    
    /* 瀑布流间距 */
    --masonry-gap: 24px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--gray-700);
    background: var(--gradient-dark);
    min-height: 100vh;
    overflow-x: hidden;
}

/* 背景装饰 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(118, 75, 162, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(79, 172, 254, 0.1) 0%, transparent 40%);
    pointer-events: none;
    z-index: -1;
}

/* 链接 */
a {
    color: var(--primary-400);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-300);
}

/* 列表 */
ul, ol {
    list-style: none;
}

/* 图片 */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* 按钮重置 */
button {
    font-family: inherit;
    font-size: inherit;
    border: none;
    background: none;
    cursor: pointer;
    outline: none;
}

/* 输入框重置 */
input, textarea, select {
    font-family: inherit;
    font-size: inherit;
    border: none;
    outline: none;
    background: none;
}

/* 选中文字样式 */
::selection {
    background: var(--primary-500);
    color: white;
}

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

::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-500);
    border-radius: var(--radius-full);
    transition: background var(--transition-fast);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-400);
}

/* ========================================
   3. 布局系统
   ======================================== */
.container {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.container-sm {
    max-width: 800px;
}

.container-lg {
    max-width: 1600px;
}

/* 网格布局 */
.grid {
    display: grid;
    gap: var(--masonry-gap);
}

/* 瀑布流容器 */
.masonry-grid {
    column-count: 4;
    column-gap: var(--masonry-gap);
}

@media (max-width: 1200px) {
    .masonry-grid {
        column-count: 3;
    }
}

@media (max-width: 900px) {
    .masonry-grid {
        column-count: 2;
    }
}

@media (max-width: 600px) {
    .masonry-grid {
        column-count: 1;
    }
}

/* 瀑布流项 */
.masonry-item {
    break-inside: avoid;
    margin-bottom: var(--masonry-gap);
}

/* Flex工具类 */
.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-sm {
    gap: var(--space-sm);
}

.gap-md {
    gap: var(--space-md);
}

.gap-lg {
    gap: var(--space-lg);
}

/* ========================================
   4. 头部区域
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--space-md) 0;
    transition: all var(--transition-base);
}

.header.scrolled {
    background: var(--glass-bg-strong);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: transform var(--transition-fast);
}

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

.logo-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

/* 导航 */
.nav {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.nav-link {
    position: relative;
    font-weight: 500;
    color: var(--gray-300);
    padding: var(--space-sm) 0;
    transition: color var(--transition-fast);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: white;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* 移动端菜单按钮 */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-sm);
}

.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: white;
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    .nav {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        flex-direction: column;
        background: var(--glass-bg-strong);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        padding: var(--space-lg);
        gap: var(--space-md);
        border-bottom: 1px solid var(--glass-border);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all var(--transition-base);
    }
    
    .nav.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }
}

/* ========================================
   5. 卡片样式（瀑布流卡片）
   ======================================== */
.card {
    position: relative;
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    transition: all var(--transition-base);
    box-shadow: var(--glass-shadow);
}

.card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-glow);
    border-color: var(--primary-400);
}

/* 卡片图片 */
.card-image {
    position: relative;
    width: 100%;
    overflow: hidden;
}

.card-image img {
    width: 100%;
    height: auto;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.card:hover .card-image img {
    transform: scale(1.1);
}

/* 卡片图片遮罩 */
.card-image::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to bottom, transparent 50%, rgba(0, 0, 0, 0.6) 100%);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.card:hover .card-image::after {
    opacity: 1;
}

/* 卡片内容 */
.card-content {
    padding: var(--space-lg);
}

.card-badge {
    display: inline-block;
    padding: var(--space-xs) var(--space-sm);
    background: var(--gradient-primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    margin-bottom: var(--space-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.card-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--space-sm);
    line-height: 1.3;
}

.card-description {
    font-size: 0.875rem;
    color: var(--gray-400);
    line-height: 1.6;
    margin-bottom: var(--space-md);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

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

.card-meta {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 0.875rem;
    color: var(--gray-400);
}

.card-meta svg {
    width: 16px;
    height: 16px;
    opacity: 0.7;
}

/* 卡片变体 - 纯文字 */
.card-text-only {
    padding: var(--space-xl);
}

.card-text-only .card-title {
    font-size: 1.5rem;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 卡片变体 - 横向布局 */
.card-horizontal {
    display: flex;
}

.card-horizontal .card-image {
    width: 40%;
    min-width: 150px;
}

.card-horizontal .card-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

@media (max-width: 600px) {
    .card-horizontal {
        flex-direction: column;
    }
    
    .card-horizontal .card-image {
        width: 100%;
    }
}

/* 卡片悬浮效果 - 3D翻转 */
.card-3d {
    perspective: 1000px;
}

.card-3d-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform var(--transition-slow);
    transform-style: preserve-3d;
}

.card-3d:hover .card-3d-inner {
    transform: rotateY(10deg) rotateX(5deg);
}

/* ========================================
   6. 按钮样式
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    font-weight: 600;
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width var(--transition-slow), height var(--transition-slow);
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

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

.btn-primary:hover {
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}

.btn-primary:active {
    transform: translateY(0);
}

/* 次要按钮 */
.btn-secondary {
    background: var(--glass-bg);
    color: white;
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: var(--glass-bg-strong);
    border-color: var(--primary-400);
    box-shadow: var(--shadow-glow);
}

/* 幽灵按钮 */
.btn-ghost {
    background: transparent;
    color: var(--gray-300);
    border: 1px solid var(--gray-600);
}

.btn-ghost:hover {
    background: var(--glass-bg);
    border-color: var(--primary-400);
    color: white;
}

/* 渐变边框按钮 */
.btn-outline-gradient {
    position: relative;
    background: var(--gradient-dark);
    color: white;
    z-index: 1;
}

.btn-outline-gradient::before {
    content: '';
    position: absolute;
    inset: -2px;
    background: var(--gradient-primary);
    border-radius: inherit;
    z-index: -1;
    opacity: 1;
    transition: opacity var(--transition-fast);
}

.btn-outline-gradient:hover::before {
    opacity: 0.8;
}

/* 按钮尺寸 */
.btn-sm {
    padding: var(--space-xs) var(--space-md);
    font-size: 0.875rem;
}

.btn-lg {
    padding: var(--space-md) var(--space-2xl);
    font-size: 1.125rem;
}

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

.btn-icon svg {
    width: 20px;
    height: 20px;
}

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

.form-label {
    display: block;
    font-weight: 500;
    color: var(--gray-300);
    margin-bottom: var(--space-sm);
    font-size: 0.875rem;
}

.form-input {
    width: 100%;
    padding: var(--space-md) var(--space-lg);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    color: white;
    font-size: 1rem;
    transition: all var(--transition-fast);
    backdrop-filter: blur(10px);
}

.form-input::placeholder {
    color: var(--gray-500);
}

.form-input:hover {
    border-color: var(--gray-500);
}

.form-input:focus {
    border-color: var(--primary-400);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

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

/* 浮动标签输入框 */
.floating-input {
    position: relative;
}

.floating-input input,
.floating-input textarea {
    padding-top: var(--space-lg);
}

.floating-input label {
    position: absolute;
    left: var(--space-lg);
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
    pointer-events: none;
    transition: all var(--transition-fast);
}

.floating-input textarea ~ label {
    top: var(--space-lg);
}

.floating-input input:focus ~ label,
.floating-input input:not(:placeholder-shown) ~ label,
.floating-input textarea:focus ~ label,
.floating-input textarea:not(:placeholder-shown) ~ label {
    top: var(--space-sm);
    font-size: 0.75rem;
    color: var(--primary-400);
}

/* 文本域 */
.form-textarea {
    min-height: 120px;
    resize: vertical;
}

/* 选择框 */
.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%239ca3af' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--space-md) center;
    background-size: 20px;
    padding-right: var(--space-2xl);
}

/* 复选框和单选框 */
.form-checkbox,
.form-radio {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    cursor: pointer;
}

.form-checkbox input,
.form-radio input {
    width: 20px;
    height: 20px;
    accent-color: var(--primary-500);
    cursor: pointer;
}

/* 搜索框 */
.search-box {
    position: relative;
    max-width: 400px;
}

.search-box input {
    padding-left: var(--space-2xl);
}

.search-box .search-icon {
    position: absolute;
    left: var(--space-md);
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
    pointer-events: none;
}

.search-box .search-icon svg {
    width: 20px;
    height: 20px;
}

/* ========================================
   8. Hero区域
   ======================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: var(--space-3xl) var(--space-lg);
    position: relative;
    overflow: hidden;
}

/* Hero几何装饰 */
.hero::before {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(102, 126, 234, 0.3) 0%, transparent 70%);
    top: -200px;
    right: -200px;
    animation: float 8s ease-in-out infinite;
}

.hero::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(118, 75, 162, 0.3) 0%, transparent 70%);
    bottom: -100px;
    left: -100px;
    animation: float 10s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0);
    }
    50% {
        transform: translate(30px, -30px);
    }
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 8vw, 4.5rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: var(--space-lg);
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeInUp 1s ease-out;
}

.hero-subtitle {
    font-size: clamp(1rem, 3vw, 1.25rem);
    color: var(--gray-400);
    margin-bottom: var(--space-xl);
    animation: fadeInUp 1s ease-out 0.2s backwards;
}

.hero-actions {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 1s ease-out 0.4s backwards;
}

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

/* 几何装饰元素 */
.geo-shape {
    position: absolute;
    opacity: 0.1;
    animation: rotate 20s linear infinite;
}

.geo-circle {
    width: 100px;
    height: 100px;
    border: 3px solid var(--primary-400);
    border-radius: 50%;
}

.geo-square {
    width: 80px;
    height: 80px;
    border: 3px solid var(--primary-400);
    transform: rotate(45deg);
}

.geo-triangle {
    width: 0;
    height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-bottom: 86px solid var(--primary-400);
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

/* ========================================
   9. 特性区块
   ======================================== */
.section {
    padding: var(--space-3xl) 0;
    position: relative;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.section-badge {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    color: var(--primary-400);
    margin-bottom: var(--space-md);
    backdrop-filter: blur(10px);
}

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    color: white;
    margin-bottom: var(--space-md);
}

.section-description {
    font-size: 1.125rem;
    color: var(--gray-400);
    max-width: 600px;
    margin: 0 auto;
}

/* 特性卡片网格 */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-xl);
}

/* 特性卡片 */
.feature-card {
    padding: var(--space-xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(16px);
    transition: all var(--transition-base);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-400);
    box-shadow: var(--shadow-glow);
}

.feature-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--space-lg);
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    transition: transform var(--transition-bounce);
}

.feature-card:hover .feature-icon {
    transform: scale(1.1) rotate(5deg);
}

.feature-icon svg {
    width: 32px;
    height: 32px;
    color: white;
}

.feature-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: white;
    margin-bottom: var(--space-sm);
}

.feature-description {
    color: var(--gray-400);
    font-size: 0.9375rem;
    line-height: 1.7;
}

/* ========================================
   10. 统计数字
   ======================================== */
.stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-xl);
    padding: var(--space-2xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    backdrop-filter: blur(16px);
}

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

@media (max-width: 480px) {
    .stats {
        grid-template-columns: 1fr;
    }
}

.stat-item {
    text-align: center;
    padding: var(--space-md);
}

.stat-number {
    font-family: var(--font-display);
    font-size: 3rem;
    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-sm);
}

.stat-label {
    color: var(--gray-400);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* ========================================
   11. 页脚
   ======================================== */
.footer {
    padding: var(--space-3xl) 0 var(--space-xl);
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(20px);
    border-top: 1px solid var(--glass-border);
    margin-top: var(--space-3xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr repeat(3, 1fr);
    gap: var(--space-2xl);
    margin-bottom: var(--space-2xl);
}

@media (max-width: 900px) {
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }
}

.footer-brand {
    max-width: 300px;
}

.footer-brand .logo {
    margin-bottom: var(--space-md);
}

.footer-brand p {
    color: var(--gray-400);
    font-size: 0.875rem;
    line-height: 1.7;
}

.footer-column h4 {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 600;
    color: white;
    margin-bottom: var(--space-md);
}

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

.footer-links a {
    color: var(--gray-400);
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary-400);
}

.footer-social {
    display: flex;
    gap: var(--space-sm);
    margin-top: var(--space-md);
}

.footer-social a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    color: var(--gray-400);
    transition: all var(--transition-fast);
}

.footer-social a:hover {
    background: var(--gradient-primary);
    border-color: transparent;
    color: white;
    transform: translateY(-3px);
}

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

.footer-copyright {
    color: var(--gray-500);
    font-size: 0.875rem;
}

/* ========================================
   12. 模态框
   ======================================== */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

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

.modal {
    background: var(--gray-800);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.9) translateY(20px);
    transition: transform var(--transition-base);
}

.modal-overlay.active .modal {
    transform: scale(1) translateY(0);
}

.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-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    color: white;
}

.modal-close {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border-radius: var(--radius-full);
    color: var(--gray-400);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--glass-bg-strong);
    color: white;
}

.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);
}

/* ========================================
   13. 提示信息
   ======================================== */
.toast-container {
    position: fixed;
    top: var(--space-xl);
    right: var(--space-xl);
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.toast {
    padding: var(--space-md) var(--space-lg);
    background: var(--glass-bg-strong);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(20px);
    color: white;
    display: flex;
    align-items: center;
    gap: var(--space-md);
    min-width: 300px;
    max-width: 400px;
    transform: translateX(100%);
    opacity: 0;
    transition: all var(--transition-base);
}

.toast.show {
    transform: translateX(0);
    opacity: 1;
}

.toast.success {
    border-left: 4px solid #10b981;
}

.toast.error {
    border-left: 4px solid #ef4444;
}

.toast.warning {
    border-left: 4px solid #f59e0b;
}

.toast.info {
    border-left: 4px solid #3b82f6;
}

/* ========================================
   14. 加载动画
   ======================================== */
.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--glass-border);
    border-top-color: var(--primary-500);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.loading-dots {
    display: flex;
    gap: var(--space-xs);
}

.loading-dots span {
    width: 8px;
    height: 8px;
    background: var(--primary-400);
    border-radius: 50%;
    animation: bounce 1.4s ease-in-out infinite;
}

.loading-dots span:nth-child(2) {
    animation-delay: 0.2s;
}

.loading-dots span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes bounce {
    0%, 80%, 100% {
        transform: scale(0);
    }
    40% {
        transform: scale(1);
    }
}

/* ========================================
   15. 响应式媒体查询
   ======================================== */
@media (max-width: 1200px) {
    :root {
        --masonry-gap: 20px;
    }
}

@media (max-width: 992px) {
    .container {
        padding: 0 var(--space-md);
    }
    
    .section {
        padding: var(--space-2xl) 0;
    }
    
    .hero {
        padding: var(--space-2xl) var(--space-md);
    }
}

@media (max-width: 768px) {
    .section-title {
        font-size: 1.75rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-actions .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .feature-card {
        padding: var(--space-lg);
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 576px) {
    :root {
        --masonry-gap: 16px;
    }
    
    .card-content {
        padding: var(--space-md);
    }
    
    .card-title {
        font-size: 1.125rem;
    }
    
    .btn-lg {
        padding: var(--space-sm) var(--space-lg);
        font-size: 1rem;
    }
    
    .stat-number {
        font-size: 2.5rem;
    }
}

/* ========================================
   16. 辅助类
   ======================================== */

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

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

/* 颜色 */
.text-primary { color: var(--primary-400); }
.text-secondary { color: var(--gray-400); }
.text-white { color: white; }

/* 字体 */
.font-bold { font-weight: 700; }
.font-medium { font-weight: 500; }
.text-sm { font-size: 0.875rem; }
.text-lg { font-size: 1.125rem; }

/* 间距 */
.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); }

/* 显示 */
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }

/* 动画辅助 */
.animate-fade-in {
    animation: fadeInUp 0.6s ease-out;
}

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

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

/* 毛玻璃容器 */
.glass-container {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
}

/* 分隔线 */
.divider {
    height: 1px;
    background: var(--glass-border);
    margin: var(--space-xl) 0;
}

/* 头像 */
.avatar {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    object-fit: cover;
    border: 2px solid var(--glass-border);
}

.avatar-sm {
    width: 32px;
    height: 32px;
}

.avatar-lg {
    width: 64px;
    height: 64px;
}

/* 徽章 */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-xs) var(--space-sm);
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--gray-300);
}

.badge-primary {
    background: var(--gradient-primary);
    border: none;
    color: white;
}

.badge-success {
    background: linear-gradient(135deg, #10b981, #059669);
    border: none;
    color: white;
}

.badge-warning {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    border: none;
    color: white;
}

.badge-error {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    border: none;
    color: white;
}

/* ========================================
   17. 打印样式
   ======================================== */
@media print {
    body {
        background: white;
        color: black;
    }
    
    .header,
    .footer,
    .btn,
    .modal-overlay,
    .toast-container {
        display: none !important;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid #ddd;
        break-inside: avoid;
    }
}
```