/* ==================== 全局样式 ==================== */
:root {
    --primary: #e63946;
    --primary-dark: #c1121f;
    --secondary: #457b9d;
    --dark: #1d3557;
    --light: #f1faee;
    --gray: #a8dadc;
    --text: #333;
    --text-light: #666;
    --border: #e0e0e0;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    line-height: 1.7;
    color: var(--text);
    background: #fff;
}

a {
    color: inherit;
    text-decoration: none;
}

ul {
    list-style: none;
}

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

.section-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 10px;
    color: var(--dark);
}

.section-desc {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 50px;
    font-size: 1.1rem;
}

/* ==================== 按钮 ==================== */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(230, 57, 70, 0.3);
}

.btn-secondary {
    background: #fff;
    color: var(--primary);
    border: 2px solid var(--primary);
}

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

.btn-large {
    padding: 15px 40px;
    font-size: 1.1rem;
}

/* ==================== 导航栏 ==================== */
.header {
    background: #fff;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.nav {
    display: flex;
    gap: 30px;
}

.nav a {
    color: var(--text);
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
}

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

.nav a.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
}

.download-btn {
    background: var(--primary);
    color: #fff;
    padding: 10px 25px;
    border-radius: 25px;
    font-weight: 600;
    transition: all 0.3s;
}

.download-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

/* ==================== 横幅 ==================== */
.hero {
    background: linear-gradient(135deg, var(--dark) 0%, var(--secondary) 100%);
    color: #fff;
    padding: 80px 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.8rem;
    margin-bottom: 20px;
}

.hero .subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 40px;
    line-height: 1.8;
}

.hero-btns {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-bottom: 50px;
}

.stats {
    display: flex;
    justify-content: center;
    gap: 60px;
}

.stat-item {
    text-align: center;
}

.stat-num {
    display: block;
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    font-size: 1rem;
    opacity: 0.8;
}

/* ==================== 公式分类 ==================== */
.formulas {
    padding: 80px 0;
    background: #f8f9fa;
}

.formula-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.formula-card {
    background: #fff;
    border-radius: 15px;
    padding: 30px;
    box-shadow: var(--shadow);
    transition: all 0.3s;
}

.formula-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.15);
}

.formula-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.formula-card h3 {
    font-size: 1.4rem;
    margin-bottom: 10px;
    color: var(--dark);
}

.formula-count {
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 15px;
}

.formula-desc {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.formula-list {
    margin-bottom: 20px;
}

.formula-list li {
    color: var(--text-light);
    font-size: 0.9rem;
    padding: 5px 0;
    border-bottom: 1px dashed #eee;
}

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

.formula-link {
    color: var(--primary);
    font-weight: 600;
}

.formula-link:hover {
    text-decoration: underline;
}

/* ==================== 最新文章 ==================== */
.articles {
    padding: 80px 0;
}

.article-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.article-card {
    background: #fff;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all 0.3s;
}

.article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.15);
}

.article-image {
    height: 180px;
    background: linear-gradient(135deg, var(--secondary), var(--dark));
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 3rem;
}

.article-content {
    padding: 25px;
}

.article-date {
    color: var(--text-light);
    font-size: 0.85rem;
    margin-bottom: 10px;
}

.article-card h3 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: var(--dark);
    line-height: 1.5;
}

.article-card h3 a:hover {
    color: var(--primary);
}

.article-excerpt {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 15px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.article-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.article-tag {
    background: #f0f0f0;
    color: var(--text-light);
    padding: 4px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
}

.article-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #eee;
}

.article-link {
    color: var(--primary);
    font-weight: 600;
}

/* ==================== APP下载 ==================== */
.app-download {
    background: linear-gradient(135deg, var(--dark) 0%, var(--secondary) 100%);
    color: #fff;
    padding: 80px 0;
}

.app-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
}

.app-info {
    flex: 1;
}

.app-info h2 {
    font-size: 2.2rem;
    margin-bottom: 20px;
}

.app-info p {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-bottom: 25px;
    line-height: 1.8;
}

.app-features {
    margin-bottom: 30px;
}

.app-features li {
    font-size: 1.05rem;
    margin-bottom: 12px;
    opacity: 0.9;
}

.app-qr {
    flex-shrink: 0;
}

.qr-box {
    background: #fff;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
}

.qr-box p {
    color: var(--text);
    font-weight: 600;
    margin-bottom: 15px;
}

.qr-placeholder {
    width: 180px;
    height: 180px;
    background: #f5f5f5;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    color: var(--text-light);
    font-size: 0.9rem;
    border-radius: 10px;
}

/* ==================== 关于我们 ==================== */
.about {
    padding: 80px 0;
    background: #f8f9fa;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-content p {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 20px;
    line-height: 1.8;
}

.disclaimer {
    background: #fff3cd;
    border: 1px solid #ffc107;
    border-radius: 10px;
    padding: 25px;
    margin-top: 30px;
    text-align: left;
}

.disclaimer h4 {
    color: #856404;
    margin-bottom: 10px;
}

.disclaimer p {
    color: #856404;
    font-size: 0.95rem;
}

.disclaimer strong {
    color: #721c24;
}

/* ==================== 页脚 ==================== */
.footer {
    background: var(--dark);
    color: #fff;
    padding: 60px 0 30px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 80px;
    margin-bottom: 40px;
}

.footer-col h4 {
    font-size: 1.1rem;
    margin-bottom: 20px;
}

.footer-col a {
    display: block;
    color: rgba(255,255,255,0.7);
    margin-bottom: 12px;
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255,255,255,0.1);
}

/* SEO内链矩阵样式 */
.seo-links {
    background: #f8f9fa;
    padding: 30px 0;
    border-top: 1px solid #eee;
}

.seo-links .section-title {
    font-size: 1.2rem;
    color: #333;
    margin-bottom: 15px;
}

.seo-links p {
    color: #555;
    margin-bottom: 15px;
    font-size: 0.95rem;
}

.seo-link-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.seo-link-grid a {
    display: inline-block;
    padding: 6px 14px;
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 4px;
    color: #457b9d;
    text-decoration: none;
    font-size: 0.85rem;
    transition: all 0.2s;
}

.seo-link-grid a:hover {
    background: #457b9d;
    color: #fff;
    border-color: #457b9d;
}

.footer-bottom p {
    color: rgba(255,255,255,0.6);
    margin-bottom: 10px;
}

.disclaimer-text {
    font-size: 0.85rem;
}

/* ==================== 响应式 ==================== */
@media (max-width: 992px) {
    .formula-grid,
    .article-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .app-content {
        flex-direction: column;
        text-align: center;
    }
    
    .stats {
        gap: 30px;
    }
    
    .stat-num {
        font-size: 2.2rem;
    }
}

@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero .subtitle {
        font-size: 1rem;
    }
    
    .hero-btns {
        flex-direction: column;
        gap: 15px;
    }
    
    .stats {
        flex-wrap: wrap;
        gap: 20px;
    }
    
    .formula-grid,
    .article-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        flex-direction: column;
        gap: 30px;
        align-items: center;
    }
    
    .section-title {
        font-size: 1.6rem;
    }
}

/* ==================== 文章详情页样式 ==================== */
.article-page {
    padding-top: 0;
}

.article-header {
    background: linear-gradient(135deg, var(--dark) 0%, var(--secondary) 100%);
    color: #fff;
    padding: 60px 0;
    text-align: center;
}

.article-header h1 {
    font-size: 2rem;
    max-width: 900px;
    margin: 0 auto 20px;
    line-height: 1.5;
}

.article-meta {
    font-size: 0.95rem;
    opacity: 0.8;
}

.article-body {
    max-width: 900px;
    margin: 0 auto;
    padding: 50px 20px;
}

.article-body h2 {
    font-size: 1.5rem;
    color: var(--dark);
    margin: 35px 0 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary);
}

.article-body h3 {
    font-size: 1.2rem;
    color: var(--dark);
    margin: 25px 0 15px;
}

.article-body p {
    margin-bottom: 18px;
    line-height: 1.9;
}

.article-body ul,
.article-body ol {
    margin: 20px 0;
    padding-left: 25px;
}

.article-body li {
    margin-bottom: 10px;
    line-height: 1.8;
}

.article-body .formula-box {
    background: #f8f9fa;
    border-left: 4px solid var(--primary);
    padding: 20px;
    margin: 25px 0;
    border-radius: 0 8px 8px 0;
}

.article-body .formula-box code {
    display: block;
    background: #fff;
    padding: 15px;
    border-radius: 5px;
    font-family: Consolas, Monaco, monospace;
    margin-top: 10px;
    overflow-x: auto;
}

.article-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 25px 0;
}

.article-body th,
.article-body td {
    border: 1px solid #ddd;
    padding: 12px;
    text-align: left;
}

.article-body th {
    background: var(--dark);
    color: #fff;
}

.article-body tr:nth-child(even) {
    background: #f8f9fa;
}

.article-related {
    background: #f8f9fa;
    padding: 50px 0;
}

.article-related .container {
    max-width: 900px;
}

.related-title {
    font-size: 1.5rem;
    margin-bottom: 30px;
    color: var(--dark);
}

.related-list {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.related-item {
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    transition: all 0.3s;
}

.related-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.related-item h4 {
    font-size: 1rem;
    margin-bottom: 10px;
    color: var(--dark);
}

.related-item h4 a:hover {
    color: var(--primary);
}

.related-item p {
    font-size: 0.85rem;
    color: var(--text-light);
}

/* ==================== 加载动画 ==================== */
.loading {
    text-align: center;
    padding: 50px;
}

.loading::after {
    content: '加载中...';
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

/* ==================== 面包屑 ==================== */
.breadcrumb {
    padding: 15px 0;
    background: #f8f9fa;
    border-bottom: 1px solid #eee;
}

.breadcrumb .container {
    max-width: 900px;
}

.breadcrumb a {
    color: var(--text-light);
}

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

.breadcrumb span {
    color: var(--text-light);
    margin: 0 10px;
}

/* ==================== 合规横幅 ==================== */
.compliance-banner {
    background: #fff3cd;
    border-bottom: 1px solid #ffc107;
    padding: 10px 0;
    text-align: center;
    font-size: 0.9rem;
    color: #856404;
}

/* ==================== 免责声明 Section ==================== */
.disclaimer-section {
    padding: 50px 0;
    background: #fff8f8;
}

.disclaimer-box {
    background: #fff;
    border: 2px solid #ffc107;
    border-radius: 12px;
    padding: 30px;
    max-width: 900px;
    margin: 0 auto;
}

.disclaimer-box h3,
.disclaimer-box h4 {
    color: #856404;
    margin-bottom: 15px;
}

.disclaimer-content ul {
    padding-left: 20px;
    list-style: disc;
}

.disclaimer-content li {
    color: #555;
    margin-bottom: 8px;
    line-height: 1.7;
}

.disclaimer-content strong {
    color: #c0392b;
}

/* ==================== 文章内 APP 链接 ==================== */
.app-link {
    display: inline-block;
    margin-top: 10px;
}

/* ==================== 分页按钮 ==================== */
.article-pagination {
    text-align: center;
    margin-top: 30px;
    display: flex;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.pagination-btn {
    padding: 6px 14px;
    border-radius: 4px;
    border: 1px solid #ccc;
    cursor: pointer;
    background: #fff;
    color: #333;
    font-size: 14px;
    transition: all 0.2s;
}

.pagination-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.pagination-btn.active {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

/* ==================== 文章页相关链接区 ==================== */
.related-articles {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 15px 0;
}

.related-link {
    display: inline-block;
    padding: 6px 14px;
    background: #f1faee;
    border: 1px solid #a8dadc;
    border-radius: 20px;
    font-size: 14px;
    color: #1d3557;
    transition: all 0.2s;
}

.related-link:hover {
    background: #1d3557;
    color: #fff;
}

/* ==================== 数据表格（文章内） ==================== */
.data-table-wrap {
    margin: 20px 0;
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

.data-table th,
.data-table td {
    border: 1px solid #ddd;
    padding: 8px 12px;
    text-align: center;
}

.data-table th {
    background: var(--dark);
    color: #fff;
}

.data-table tr:nth-child(even) {
    background: #f5f5f5;
}

.num-cell {
    font-family: Consolas, Monaco, monospace;
    font-size: 16px;
    font-weight: bold;
    color: var(--primary);
    letter-spacing: 2px;
}

.table-caption {
    font-size: 13px;
    color: #666;
    margin-bottom: 8px;
}

.table-note {
    font-size: 12px;
    color: #999;
    margin-top: 8px;
    font-style: italic;
}

.formula-note {
    font-size: 13px;
    color: var(--primary);
    margin-top: 8px;
}

/* ==================== 文章列表 Section 总数提示 ==================== */
.articles-count {
    text-align: center;
    color: var(--text-light);
    font-size: 0.9rem;
    margin-top: 20px;
}

@media (max-width: 768px) {
    .article-header h1 {
        font-size: 1.4rem;
    }
    .related-list {
        grid-template-columns: 1fr;
    }
}