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

:root {
    --primary-color: #0073bc;
    --secondary-color: #005a94;
    --accent-color: #ff6b35;
    --text-color: #333;
    --text-light: #666;
    --bg-light: #f5f5f5;
    --white: #fff;
    --border-color: #e0e0e0;
    --shadow: 0 4px 20px rgba(0,0,0,0.1);
}

body {
    font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--white);
}

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

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

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

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

/* ========== 按钮 ========== */
.btn-primary, .btn-secondary {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 4px;
    font-size: 16px;
    transition: all 0.3s;
    cursor: pointer;
}

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

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

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

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

/* ========== 标题 ========== */
.section-title {
    text-align: center;
    font-size: 36px;
    color: var(--text-color);
    margin-bottom: 15px;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--primary-color);
    margin: 15px auto 0;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 18px;
    margin-bottom: 50px;
}

.section {
    padding: 80px 0;
}

/* ========== 头部 ========== */
.header {
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo img {
    height: 60px;
}

.brand-name {
    font-size: 24px;
    font-weight: bold;
    color: #0ea5e9;
    margin-left: 15px;
    padding-left: 15px;
    border-left: 2px solid #e2e8f0;
}

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

.nav > ul > li {
    position: relative;
}

.nav > ul > li > a {
    display: block;
    padding: 10px 0;
    font-size: 16px;
    color: var(--text-color);
    transition: color 0.3s;
}

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

/* 下拉菜单 */
.nav-down {
    position: absolute;
    top: 100%;
    left: 0;
    background: var(--white);
    box-shadow: var(--shadow);
    min-width: 180px;
    display: none;
    visibility: hidden;
    opacity: 0;
    z-index: 9999;
    border-radius: 4px;
    overflow: hidden;
}

.nav > ul > li:hover .nav-down {
    display: block;
    visibility: visible;
    opacity: 1;
}

.nav-down li a {
    display: block;
    padding: 12px 20px;
    font-size: 14px;
    color: var(--text-color);
    transition: all 0.3s;
}

.nav-down li a:hover {
    background: var(--primary-color);
    color: var(--white);
}

/* ========== Banner ========== */
.banner {
    position: relative;
    height: 500px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    overflow: hidden;
}

.banner-slide img {
    width: 100%;
    height: 500px;
    object-fit: cover;
}

.banner-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: var(--white);
}

.banner-text h1 {
    font-size: 48px;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.banner-text p {
    font-size: 24px;
    margin-bottom: 30px;
    opacity: 0.9;
}

/* ========== 核心优势 ========== */
.advantages {
    background: var(--bg-light);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.advantage-item {
    text-align: center;
    padding: 40px 20px;
    background: var(--white);
    border-radius: 8px;
    transition: transform 0.3s;
}

.advantage-item:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow);
}

.advantage-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.advantage-item h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--primary-color);
}

.advantage-item p {
    color: var(--text-light);
    font-size: 14px;
}

/* ========== 产品展示 ========== */
.products-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.product-card {
    background: var(--white);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
    transition: all 0.3s;
}

.product-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow);
}

.product-card img {
    height: 200px;
    object-fit: cover;
}

.product-info {
    padding: 20px;
}

.product-info h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.product-info p {
    color: var(--text-light);
    font-size: 14px;
    margin-bottom: 15px;
}

.link-more {
    color: var(--primary-color);
    font-size: 14px;
}

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

/* ========== 应用场景 ========== */
.scenarios {
    background: var(--bg-light);
}

.scenarios-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.scenario-item {
    position: relative;
    border-radius: 8px;
    overflow: hidden;
}

.scenario-item img {
    height: 250px;
    object-fit: cover;
    transition: transform 0.5s;
}

.scenario-item:hover img {
    transform: scale(1.1);
}

.scenario-content {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 30px;
    background: linear-gradient(transparent, rgba(0,0,0,0.8));
    color: var(--white);
}

.scenario-content h3 {
    font-size: 24px;
    margin-bottom: 8px;
}

/* ========== 知识中心 ========== */
.knowledge-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.knowledge-card {
    background: var(--white);
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
    transition: all 0.3s;
}

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

.knowledge-card .tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--primary-color);
    color: var(--white);
    font-size: 12px;
    border-radius: 20px;
    margin-bottom: 15px;
}

.knowledge-card h3 {
    font-size: 18px;
    margin-bottom: 15px;
    line-height: 1.4;
}

.knowledge-card p {
    color: var(--text-light);
    font-size: 14px;
    margin-bottom: 20px;
    line-height: 1.6;
}

.knowledge-card a {
    color: var(--primary-color);
    font-size: 14px;
}

/* ========== 案例预览 ========== */
.cases-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.case-card {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

.case-card img {
    height: 220px;
    object-fit: cover;
    transition: transform 0.5s;
}

.case-card:hover img {
    transform: scale(1.05);
}

.case-info {
    padding: 20px;
    background: var(--white);
}

.case-info h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.case-info p {
    color: var(--text-light);
    font-size: 14px;
}

/* ========== 合作流程 ========== */
.partners {
    background: var(--bg-light);
}

.process-steps {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    margin-top: 50px;
}

.step {
    text-align: center;
    padding: 30px;
    background: var(--white);
    border-radius: 8px;
    width: 150px;
}

.step-num {
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: bold;
    margin: 0 auto 15px;
}

.step h3 {
    font-size: 16px;
    margin-bottom: 8px;
}

.step p {
    color: var(--text-light);
    font-size: 14px;
}

.step-arrow {
    font-size: 24px;
    color: var(--primary-color);
}

/* ========== 底部 ========== */
.footer {
    background: #1a1a2e;
    color: #fff;
    padding: 60px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    font-size: 18px;
    margin-bottom: 20px;
    color: var(--white);
}

.footer-col p {
    color: #999;
    font-size: 14px;
    line-height: 2;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a {
    color: #999;
    font-size: 14px;
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #333;
    color: #666;
    font-size: 14px;
}

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

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        height: auto;
        padding: 15px;
    }
    
    .nav ul {
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
    }
    
    .advantages-grid,
    .products-grid,
    .knowledge-grid,
    .cases-grid,
    .scenarios-grid,
    .footer-grid {
        grid-template-columns: 1fr;
    }
    
    .process-steps {
        flex-direction: column;
    }
    
    .step-arrow {
        transform: rotate(90deg);
    }
    
    .banner {
        height: 300px;
    }
    
    .banner-text h1 {
        font-size: 28px;
    }
    
    .section-title {
        font-size: 28px;
    }
}

/* ========== 顶部联系电话横幅 ========== */
.top-contact-banner {
    background: linear-gradient(90deg, #0073bc 0%, #005a94 100%);
    text-align: center;
    padding: 8px 20px;
    position: relative;
    z-index: 1001;
}
.top-contact-banner a {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: #ffffff;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 0.5px;
    transition: opacity 0.3s ease;
}
.top-contact-banner a:hover {
    opacity: 0.85;
}
.top-contact-banner i {
    font-size: 13px;
}

/* 首页工程案例居中样式 */
.cases-preview .cases-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.cases-preview .case-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

.cases-preview .case-card img {
    width: 100%;
    height: 220px;
    object-fit: cover;
    transition: transform 0.5s;
}

.cases-preview .case-card:hover img {
    transform: scale(1.05);
}

.cases-preview .case-info {
    padding: 20px;
    background: var(--white);
    width: 100%;
    box-sizing: border-box;
}

.cases-preview .case-info h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.cases-preview .case-info p {
    color: var(--text-light);
    font-size: 14px;
}

/* 移动端适配 */
@media (max-width: 768px) {
    .cases-preview .cases-grid {
        grid-template-columns: 1fr;
    }
}

/* 知识中心页面样式 */
.knowledge-hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 80px 0;
    color: #fff;
    text-align: center;
}
.knowledge-hero h1 { font-size: 42px; margin-bottom: 20px; }
.knowledge-hero p { font-size: 20px; opacity: 0.9; }

.knowledge-section {
    padding: 60px 0;
    border-bottom: 1px solid #eee;
}
.knowledge-section:last-child { border-bottom: none; }

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

.article-card {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    transition: all 0.3s;
}
.article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}
.article-card .article-img {
    height: 200px;
    overflow: hidden;
}
.article-card .article-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.article-card .article-content {
    padding: 20px;
}
.article-card .article-tag {
    display: inline-block;
    padding: 4px 12px;
    background: #0073bc;
    color: #fff;
    border-radius: 20px;
    font-size: 12px;
    margin-bottom: 10px;
}
.article-card h3 {
    font-size: 18px;
    margin-bottom: 10px;
    color: #333;
}
.article-card p {
    color: #666;
    font-size: 14px;
    line-height: 1.6;
}
.article-card .article-meta {
    margin-top: 15px;
    color: #999;
    font-size: 12px;
}

/* 技术文章 - 序号卡片样式 */
.tech-articles-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
    margin-top: 30px;
}
.tech-article-card {
    display: flex;
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    transition: all 0.3s;
}
.tech-article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}
.tech-article-card .article-num {
    width: 80px;
    background: #0073bc;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: bold;
}
.tech-article-card .article-body {
    padding: 20px;
    flex: 1;
}
.tech-article-card h3 {
    font-size: 18px;
    margin-bottom: 10px;
}
.tech-article-card p {
    color: #666;
    font-size: 14px;
}

/* 常见问题样式 */
.faq-list {
    margin-top: 30px;
}
.faq-item {
    background: #fff;
    border-radius: 8px;
    margin-bottom: 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.faq-question {
    padding: 20px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    color: #333;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.faq-question::after {
    content: '+';
    font-size: 20px;
    color: #0073bc;
}
.faq-item.active .faq-question::after {
    content: '-';
}
.faq-answer {
    padding: 0 20px 20px;
    color: #666;
    line-height: 1.8;
    display: none;
}
.faq-item.active .faq-answer {
    display: block;
}

/* 采购指南样式 */
.guide-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-top: 30px;
}
.guide-card {
    background: #fff;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    text-align: center;
}
.guide-card h3 {
    font-size: 18px;
    margin-bottom: 15px;
    color: #333;
}
.guide-card p {
    color: #666;
    font-size: 14px;
    line-height: 1.6;
}

/* 移动端适配 */
@media (max-width: 768px) {
    .article-grid, .tech-articles-list, .guide-grid {
        grid-template-columns: 1fr;
    }
    .knowledge-hero h1 {
        font-size: 28px;
    }
    .tech-article-card {
        flex-direction: column;
    }
    .tech-article-card .article-num {
        width: 100%;
        padding: 15px;
    }
}