:root {
    --dark-bg: #1a1a1a;
    --mid-dark-bg: #222222;
    --card-bg: #2b2b2b;
    --text-light: #e0e0e0;
    --text-mid: #b0b0b0;
    --accent-start: #667eea;
    --accent-end: #764ba2;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --border-color: #3a3a3a;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--dark-bg);
    color: var(--text-light);
    overflow-x: hidden;
}

.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    /* 暗色透明导航栏 */
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(10px);
    /* 深色阴影 */
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.4);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    box-shadow: 0 2px 30px rgba(0, 0, 0, 0.6);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 28px;
    font-weight: 700;
    /* 保持渐变Logo */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 40px;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    /* 导航链接颜色 */
    color: var(--text-mid);
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    /* 保持渐变下划线 */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    /* 鼠标悬停变亮 */
    color: var(--text-light);
}

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

/* 英雄区 */
.hero {
    margin-top: 80px;
    padding: 100px 40px;
    text-align: center;
    /* 暗色渐变背景 */
    background: linear-gradient(135deg, #1b2735 0%, #090a0f 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    /* 气泡颜色适应暗色 */
    background: radial-gradient(circle, rgba(118, 75, 162, 0.1) 0%, transparent 70%);
    animation: rotate 20s linear infinite;
}

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

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 900px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 56px;
    font-weight: 800;
    margin-bottom: 20px;
    /* 保持渐变标题 */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeInUp 1s ease;
}

.hero p {
    font-size: 24px;
    /* 英雄区副标题颜色 */
    color: var(--text-mid);
    margin-bottom: 40px;
    animation: fadeInUp 1s ease 0.2s both;
}

.cta-button {
    display: inline-block;
    padding: 18px 50px;
    /* 保持渐变按钮 */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    color: white;
    text-decoration: none;
    border-radius: 50px;
    font-size: 18px;
    font-weight: 600;
    transition: all 0.3s ease;
    /* 按钮阴影适应暗色 */
    box-shadow: 0 10px 30px rgba(118, 75, 162, 0.4);
    animation: fadeInUp 1s ease 0.4s both;
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(118, 75, 162, 0.6);
}

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

/* 容器 */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 40px;
}

.section {
    padding: 100px 0;
}

.section-title {
    text-align: center;
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 60px;
    /* 标题颜色 */
    color: var(--text-light);
}

/* 模型介绍区域样式 */
.model-intro-content {
    max-width: 1000px;
    margin: 0 auto;
    text-align: center;
}

.model-intro-content p {
    font-size: 18px;
    color: var(--text-mid);
    line-height: 1.8;
    margin-bottom: 40px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    text-align: left;
}

.feature-card {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(102, 126, 234, 0.2);
    border-color: var(--accent-start);
}

.feature-card h4 {
    font-size: 20px;
    color: var(--accent-start);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
}

.feature-icon {
    font-size: 24px;
    margin-right: 10px;
    line-height: 1;
}

.feature-card p {
    font-size: 15px;
    color: var(--text-mid);
    margin-bottom: 0;
}


/* 新闻区域 */
.news-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-top: 40px;
}

.featured-news {
    /* 保持渐变背景 */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    border-radius: 20px;
    padding: 50px;
    color: white;
    /* 阴影适应暗色 */
    box-shadow: 0 20px 60px rgba(102, 126, 234, 0.3);
    transition: all 0.4s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.featured-news::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    /* 气泡颜色适应暗色 */
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    transition: transform 0.6s ease;
}

.featured-news:hover::before {
    transform: scale(1.2);
}

.featured-news:hover {
    transform: translateY(-10px);
    box-shadow: 0 30px 80px rgba(102, 126, 234, 0.4);
}

.featured-badge {
    display: inline-block;
    padding: 8px 20px;
    /* 徽章背景适应暗色 */
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
}

.featured-news h3 {
    font-size: 32px;
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
}

.featured-news p {
    font-size: 18px;
    line-height: 1.8;
    margin-bottom: 25px;
    opacity: 0.95;
    position: relative;
    z-index: 1;
}

.featured-date {
    font-size: 14px;
    opacity: 0.8;
    position: relative;
    z-index: 1;
}

.view-more-btn {
    display: inline-block;
    padding: 12px 30px;
    /* 按钮背景适应暗色 */
    background: rgba(255, 255, 255, 0.9);
    color: var(--accent-start);
    text-decoration: none;
    border-radius: 25px;
    font-size: 16px;
    font-weight: 600;
    transition: all 0.3s ease;
    position: relative;
    z-index: 1;
    margin-top: 10px;
}

.view-more-btn:hover {
    background: white;
    transform: translateX(5px);
}

.news-grid {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.news-card {
    background: transparent;
    border-radius: 0;
    padding: 20px 0;
    box-shadow: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border-left: none;
    /* 分隔线适应暗色 */
    border-bottom: 1px solid var(--border-color);
}

.news-card:hover {
    transform: none;
    box-shadow: none;
    /* 悬停背景适应暗色 */
    background: var(--mid-dark-bg);
    padding-left: 15px;
}

.news-card h4 {
    font-size: 16px;
    margin-bottom: 8px;
    /* 标题颜色 */
    color: var(--text-light);
    display: block;
    -webkit-line-clamp: unset;
    -webkit-box-orient: unset;
    overflow: visible;
    transition: color 0.3s ease;
}

.news-card:hover h4 {
    /* 悬停标题颜色 */
    color: var(--accent-start);
}

.news-card .news-date {
    /* 日期颜色 */
    color: var(--text-mid);
    font-size: 13px;
}

/* AI模型系列区域 */
.models-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
    margin-top: 40px;
}

.model-card {
    /* 卡片背景适应暗色 */
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    /* 阴影适应暗色 */
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    transition: all 0.4s ease;
    position: relative;
    overflow: hidden;
}

.model-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    /* 保持渐变顶部条 */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    transform: scaleX(0);
    transition: transform 0.4s ease;
}

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

.model-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.model-rank {
    display: inline-block;
    padding: 8px 20px;
    /* 保持渐变徽章 */
    background: linear-gradient(135deg, var(--accent-start) 0%, var(--accent-end) 100%);
    color: white;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
}

.model-card h3 {
    font-size: 28px;
    margin-bottom: 15px;
    /* 标题颜色 */
    color: var(--text-light);
}

.model-card p {
    /* 描述颜色 */
    color: var(--text-mid);
    line-height: 1.8;
    font-size: 16px;
}

.model-highlight {
    margin-top: 20px;
    padding: 15px;
    /* 高亮背景适应暗色 */
    background: var(--mid-dark-bg);
    border-radius: 10px;
    color: var(--accent-start);
    font-weight: 600;
}

/* 研究报告区域 - 新样式 */
.reports-grid {
    display: grid;
    grid-template-columns: 1fr 1fr; /* 左右两栏布局 */
    gap: 40px; /* 栏间距 */
    margin-top: 40px;
}

.reports-column {
    display: flex;
    flex-direction: column;
    gap: 25px; /* 报告卡片间距 */
}

.report-card {
    display: flex;
    align-items: center;
    gap: 15px;
    /* 报告卡片背景适应暗色 */
    background: var(--card-bg);
    border-radius: 12px;
    padding: 15px;
    text-decoration: none;
    color: var(--text-light);
    /* 阴影适应暗色 */
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
    /* 边框适应暗色 */
    border: 1px solid var(--border-color);
}

.report-card:hover {
    transform: translateY(-5px);
    /* 悬停阴影和边框适应暗色 */
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.25);
    border-color: var(--accent-start);
}

.report-thumbnail {
    width: 80px;
    height: 80px;
    flex-shrink: 0;
    border-radius: 8px;
    overflow: hidden;
    /* 报告缩略图边框 */
    border: 1px solid var(--border-color);
}

.report-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.report-info {
    flex: 1;
}

.report-title {
    font-size: 16px;
    font-weight: 600;
    /* 报告标题颜色 */
    color: var(--text-light);
    margin-bottom: 6px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.5;
}

.report-meta {
    font-size: 12px;
    /* 报告元数据颜色 */
    color: var(--text-mid);
}

/* 页脚 */
.footer {
    /* 页脚背景与整体背景保持一致或更深 */
    background: var(--dark-bg);
    color: #fff;
    padding: 60px 40px 30px;
    margin-top: 100px;
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
    /* 页脚标题颜色 */
    color: var(--accent-start);
}

.footer-section p, .footer-section a {
    /* 页脚文本/链接颜色 */
    color: var(--text-mid);
    line-height: 2;
    text-decoration: none;
    display: block;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    /* 悬停颜色 */
    color: var(--accent-start);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    /* 分隔线适应暗色 */
    border-top: 1px solid var(--border-color);
    color: var(--text-mid);
    font-size: 14px;
}

.footer-bottom a {
    color: var(--text-mid);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-bottom a:hover {
    color: var(--accent-start);
}

@media (max-width: 1024px) {
    .news-layout {
        grid-template-columns: 1fr;
    }

    .news-grid {
        grid-template-columns: 1fr;
    }
    /* 报告区域在小屏幕上变成单栏 */
    .reports-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero h1 {
        font-size: 36px;
    }

    .hero p {
        font-size: 18px;
    }

    .section-title {
        font-size: 32px;
    }

    .models-grid {
        grid-template-columns: 1fr;
    }
    /* 报告区域在小屏幕上变成单栏 */
    .reports-grid {
        grid-template-columns: 1fr;
    }

    .featured-news {
        padding: 30px;
    }

    .featured-news h3 {
        font-size: 24px;
    }
    .feature-grid {
        grid-template-columns: 1fr;
    }
}

.news-card {
    text-decoration: none;
    color: inherit;
    display: block;
}

.news-card:hover {

    background: var(--mid-dark-bg);
    padding-left: 15px;
    border-radius: 8px;
}

.news-card h4,
.news-card .news-date {
    margin: 0;
}