/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根变量定义 */
:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-dark: #2d3748;
    --text-light: #718096;
    --bg-light: #f7fafc;
    --bg-white: #ffffff;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 基础元素样式 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header 样式 */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    transition: var(--transition);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo span {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-left: 0.5rem;
}

.nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

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

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-dark);
    transition: var(--transition);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.9) 0%, rgba(118, 75, 162, 0.9) 100%);
    color: white;
    padding: 120px 0 80px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 3rem;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 4rem;
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.8;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: white;
    color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

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

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: var(--primary-color);
}

.btn-outline {
    background: transparent;
    color: var(--text-dark);
    border: 2px solid var(--border-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Charts Section */
.charts {
    background: var(--bg-light);
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-dark);
}

.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.chart-card {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.chart-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: scaleX(0);
    transition: var(--transition);
}

.chart-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.chart-card:hover::before {
    transform: scaleX(1);
}

.chart-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.chart-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 12px;
}

.chart-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-dark);
}

.chart-content h4 {
    font-size: 1.125rem;
    font-weight: 500;
    margin-bottom: 0.75rem;
    color: var(--text-dark);
}

.chart-content p {
    color: var(--text-light);
    margin-bottom: 1rem;
    line-height: 1.6;
}

.features {
    list-style: none;
    margin-bottom: 1.5rem;
}

.features li {
    padding: 0.25rem 0;
    color: var(--text-light);
    position: relative;
    padding-left: 1.5rem;
}

.features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 600;
}

.view-more {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.view-more:hover {
    color: var(--secondary-color);
}

/* Full Visualization Section */
.full-visualization {
    background: white;
    padding: 80px 0;
}

.visualization-container {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 2rem;
    align-items: center;
}

.main-chart {
    width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
}

.chart-info h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.chart-info p {
    color: var(--text-light);
    margin-bottom: 2rem;
    line-height: 1.6;
}

/* Features Section */
.features {
    background: var(--bg-light);
    padding: 80px 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Download Section */
.download {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 80px 0;
}

.download-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.download-info h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.download-info p {
    margin-bottom: 2rem;
    opacity: 0.9;
}

.download-features {
    list-style: none;
}

.download-features li {
    padding: 0.5rem 0;
    opacity: 0.9;
}

.download-buttons {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.download-buttons .btn {
    justify-content: center;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.download-buttons .btn:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Footer */
.footer {
    background: var(--text-dark);
    color: white;
    padding: 40px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    color: white;
}

.footer-section p {
    opacity: 0.8;
    line-height: 1.6;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    text-align: center;
    opacity: 0.6;
}

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

/* 响应式设计 */
@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 2rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
    }
    
    .visualization-container {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .download-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 100px 0 60px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .chart-card {
        padding: 1.5rem;
    }
    
    .stat-number {
        font-size: 2rem;
    }
}

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

::-webkit-scrollbar-track {
    background: var(--bg-light);
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(var(--primary-color), var(--secondary-color));
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}

/* 选择文本样式 */
::selection {
    background: var(--accent-color);
    color: white;
}