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

/* CSS 变量定义 */
:root {
    --primary-color: #4f46e5;
    --primary-dark: #4338ca;
    --secondary-color: #06b6d4;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 基础样式 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-light);
}

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

/* 导航栏样式 */
.navbar {
    background-color: var(--bg-white);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

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

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand 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;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 3px 0;
    transition: var(--transition);
    border-radius: 3px;
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* 英雄区样式 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 100px 20px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

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

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

.hero-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease 0.2s both;
}

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

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
}

.stat-label {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.8);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* 板块样式 */
.section {
    padding: 80px 0;
}

.section-alt {
    background-color: var(--bg-white);
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* 卡片网格 */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

/* 卡片样式 */
.card {
    background-color: var(--bg-white);
    border-radius: 12px;
    overflow: hidden;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    position: relative;
    border: 1px solid var(--border-color);
}

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

.card-featured {
    grid-column: span 1;
}

.card-badge {
    position: absolute;
    top: 20px;
    right: 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.card-content {
    padding: 2rem;
}

.card-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.card-description {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.card-meta {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.meta-tag {
    display: inline-block;
    padding: 4px 12px;
    background-color: var(--bg-light);
    color: var(--text-secondary);
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 500;
}

.card-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    transition: var(--transition);
}

.card-link:hover {
    transform: translateX(4px);
}

/* 关于板块 */
.about-content {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
}

.about-text {
    font-size: 1.125rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 3rem;
}

.about-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature {
    padding: 2rem;
    background-color: var(--bg-white);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.feature h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

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

/* 页脚 */
.footer {
    background-color: var(--text-primary);
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 80px;
}

.footer p {
    opacity: 0.9;
}

/* 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-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-lg);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-stats {
        gap: 2rem;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .card-featured {
        grid-column: span 1;
    }
    
    .about-features {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .hero {
        padding: 60px 20px;
    }
    
    .section {
        padding: 60px 0;
    }
}

/* 页面内容样式（用于各个独立页面） */
.page-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 60px 20px;
    text-align: center;
    color: white;
}

.page-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.page-meta {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
    margin-top: 1rem;
}

.page-meta span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.content-wrapper {
    max-width: 900px;
    margin: 0 auto;
    padding: 60px 20px;
}

.content-section {
    margin-bottom: 3rem;
}

.content-section h2 {
    font-size: 1.875rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--primary-color);
}

.content-section h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin: 2rem 0 1rem;
}

.content-section p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.content-section ul,
.content-section ol {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-left: 2rem;
    margin-bottom: 1.5rem;
}

.content-section li {
    margin-bottom: 0.5rem;
}

.highlight-box {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.1), rgba(6, 182, 212, 0.1));
    border-left: 4px solid var(--primary-color);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 2rem 0;
}

.code-block {
    background-color: #1f2937;
    color: #e5e7eb;
    padding: 1.5rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 1.5rem 0;
    font-family: 'Courier New', monospace;
}

.back-link {
    display: inline-flex;
    align-items: center;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    margin-bottom: 2rem;
    transition: var(--transition);
}

.back-link:hover {
    transform: translateX(-4px);
}