/* ========================================
   上海信以链数字科技有限公司 - 企业网站
   响应式样式表 - 支持PC端和手机端
   ======================================== */

/* 基础重置 */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

:root{
    --primary:#1a73e8;
    --primary-dark:#1557b0;
    --secondary:#0d9488;
    --accent:#f59e0b;
    --dark:#1e293b;
    --gray:#64748b;
    --light-gray:#f1f5f9;
    --white:#ffffff;
    --shadow:0 4px 6px -1px rgba(0,0,0,0.1),0 2px 4px -2px rgba(0,0,0,0.1);
    --shadow-lg:0 10px 15px -3px rgba(0,0,0,0.1),0 4px 6px -4px rgba(0,0,0,0.1);
    --radius:8px;
    --max-width:1200px;
}

html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;color:var(--dark);line-height:1.6;font-size:16px;background:var(--white)}
a{text-decoration:none;color:inherit}
img{max-width:100%;height:auto}
ul{list-style:none}
.container{max-width:var(--max-width);margin:0 auto;padding:0 20px}

/* 头部导航 */
.header{background:var(--white);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{display:flex;align-items:center;font-size:1.5rem;font-weight:700;color:var(--primary)}
.logo img{height:40px}
.logo-text{font-size:1.5rem;font-weight:700;color:var(--primary)}
.nav ul{display:flex;gap:8px}
.nav a{display:block;padding:8px 16px;border-radius:var(--radius);font-size:0.95rem;transition:all 0.3s}
.nav a:hover,.nav a.active{background:var(--primary);color:var(--white)}
.menu-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:10px;z-index:1001}
.menu-toggle span{display:block;width:25px;height:2px;background:var(--dark);transition:all 0.3s}

/* 主横幅 */
.hero{position:relative;background:linear-gradient(135deg,#1a73e8 0%,#0d6efd 30%,#6610f2 70%,#6f42c1 100%);color:var(--white);padding:100px 0;text-align:center;overflow:hidden}
.hero-overlay{position:absolute;inset:0;background:url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="rgba(255,255,255,0.05)" d="M0,96L48,112C96,128,192,160,288,186.7C384,213,480,235,576,213.3C672,192,768,128,864,128C960,128,1056,192,1152,208C1248,224,1344,192,1392,176L1440,160L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"/></svg>') no-repeat bottom;background-size:cover}
.hero-content{position:relative;z-index:1}
.hero h1{font-size:clamp(2rem,5vw,3.5rem);margin-bottom:16px;font-weight:800}
.hero-subtitle{font-size:clamp(1.1rem,2.5vw,1.5rem);margin-bottom:12px;opacity:0.95}
.hero-desc{font-size:1.05rem;margin-bottom:32px;opacity:0.85;max-width:700px;margin-left:auto;margin-right:auto}
.hero-buttons{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}
.btn{display:inline-block;padding:14px 36px;border-radius:50px;font-size:1rem;font-weight:600;cursor:pointer;transition:all 0.3s;border:2px solid transparent}
.btn-primary{background:var(--white);color:var(--primary)}
.btn-primary:hover{background:#e8f0fe;transform:translateY(-2px);box-shadow:var(--shadow-lg)}
.btn-outline{border-color:var(--white);color:var(--white)}
.btn-outline:hover{background:rgba(255,255,255,0.15);transform:translateY(-2px)}
.btn-link{color:var(--primary);font-weight:600;transition:color 0.3s}
.btn-link:hover{color:var(--primary-dark)}

/* 通用区块样式 */
section{padding:80px 0}
.section-title{text-align:center;margin-bottom:50px}
.section-title h2{font-size:clamp(1.5rem,4vw,2.2rem);margin-bottom:12px;color:var(--dark)}
.section-title p{font-size:1.05rem;color:var(--gray);max-width:600px;margin:0 auto}

/* 特性卡片 */
.features{background:var(--light-gray)}
.features-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:24px}
.feature-card{background:var(--white);padding:36px 28px;border-radius:var(--radius);box-shadow:var(--shadow);text-align:center;transition:transform 0.3s,box-shadow 0.3s}
.feature-card:hover{transform:translateY(-5px);box-shadow:var(--shadow-lg)}
.feature-icon{font-size:3rem;margin-bottom:16px}
.feature-icon img{width:60px;height:60px}
.icon-fallback{font-size:3rem}
.feature-card h3{font-size:1.2rem;margin-bottom:12px}
.feature-card p{color:var(--gray);font-size:0.95rem}

/* 业务板块 */
.business-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:24px}
.business-card{border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);transition:transform 0.3s}
.business-card:hover{transform:translateY(-5px);box-shadow:var(--shadow-lg)}
.business-img{padding:40px 30px;color:var(--white);position:relative;min-height:140px;display:flex;flex-direction:column;justify-content:center}
.business-num{font-size:3rem;font-weight:800;opacity:0.3;position:absolute;right:20px;top:10px}
.business-img h3{font-size:1.4rem;position:relative;z-index:1}
.business-body{padding:24px;background:var(--white)}
.business-body p{color:var(--gray);margin-bottom:16px}

/* 案例预览 */
.cases-preview{background:var(--light-gray)}
.case-highlight{background:var(--white);border-radius:var(--radius);padding:40px;box-shadow:var(--shadow);max-width:800px;margin:0 auto}
.case-badge{display:inline-block;background:var(--accent);color:var(--white);padding:4px 12px;border-radius:20px;font-size:0.85rem;font-weight:600;margin-bottom:16px}
.case-content h3{font-size:1.4rem;margin-bottom:16px}
.case-content p{color:var(--gray);margin-bottom:24px}
.case-stats{display:flex;gap:30px;flex-wrap:wrap;margin-bottom:24px}
.stat-item{text-align:center}
.stat-label{display:block;font-size:0.85rem;color:var(--gray)}
.stat-value{display:block;font-size:1.5rem;font-weight:700;color:var(--primary)}

/* 页面横幅 */
.page-banner{background:linear-gradient(135deg,#1a73e8,#6610f2);color:var(--white);padding:60px 0;text-align:center}
.page-banner h1{font-size:clamp(1.8rem,4vw,2.5rem);margin-bottom:8px}
.breadcrumb{font-size:0.9rem;opacity:0.85}
.breadcrumb a{color:var(--white);text-decoration:underline}

/* 关于页面 */
.about-grid{display:grid;grid-template-columns:2fr 1fr;gap:40px;align-items:start}
.about-text h2{font-size:1.8rem;margin-bottom:20px}
.about-text h3{font-size:1.3rem;margin:30px 0 16px}
.about-text p{margin-bottom:16px;color:#334155}
.timeline li{padding:12px 0 12px 24px;border-left:3px solid var(--primary);position:relative;margin-bottom:8px}
.timeline li::before{content:'';position:absolute;left:-9px;top:18px;width:15px;height:15px;background:var(--primary);border-radius:50%}
.timeline strong{display:block;color:var(--primary);margin-bottom:4px}
.about-card{background:var(--light-gray);padding:24px;border-radius:var(--radius)}
.about-card h3{margin-bottom:16px}
.about-card li{padding:6px 0;font-size:0.95rem}

.culture-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:24px}
.culture-item{background:var(--light-gray);padding:32px;border-radius:var(--radius);text-align:center}
.culture-item h3{color:var(--primary);margin-bottom:12px}
.culture-item p{color:var(--gray)}

/* 服务详情 */
.service-item{background:var(--white);border:1px solid #e2e8f0;border-radius:var(--radius);padding:32px;margin-bottom:24px}
.service-header{display:flex;align-items:center;gap:12px;margin-bottom:16px}
.service-icon{font-size:2rem}
.service-header h2{font-size:1.5rem}
.service-item p{color:var(--gray);margin-bottom:16px}
.service-item ul{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:8px}
.service-item li{padding:8px 0;font-size:0.95rem}
.service-item li::before{content:'✓ ';color:var(--secondary);font-weight:700}

.tech-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:16px}
.tech-card{background:var(--light-gray);padding:20px;border-radius:var(--radius);text-align:center}
.tech-card h3{font-size:1rem;color:var(--primary);margin-bottom:8px}
.tech-card p{font-size:0.85rem;color:var(--gray)}

/* 产品中心 */
.product-hero{text-align:center;margin-bottom:50px}
.product-hero h2{font-size:clamp(1.5rem,3vw,2rem);color:var(--primary)}
.product-subtitle{font-size:1.1rem;color:var(--gray);margin-top:8px}
.product-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:24px}
.product-card{background:var(--white);border:1px solid #e2e8f0;border-radius:var(--radius);padding:30px;transition:box-shadow 0.3s}
.product-card:hover{box-shadow:var(--shadow-lg)}
.product-card h3{font-size:1.2rem;margin-bottom:12px}
.product-card p{color:var(--gray);margin-bottom:16px;font-size:0.95rem}
.product-card li{padding:4px 0;font-size:0.9rem}
.product-card li::before{content:'• ';color:var(--primary)}

.advantages-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:24px}
.advantage-item{background:var(--light-gray);padding:24px;border-radius:var(--radius);text-align:center}
.advantage-item h3{color:var(--primary);margin-bottom:8px}

/* 案例列表 */
.case-card-full{background:var(--white);border-radius:var(--radius);padding:32px;margin-bottom:24px;box-shadow:var(--shadow)}
.case-card-full h3{font-size:1.3rem;margin:12px 0}
.case-meta{color:var(--gray);font-size:0.9rem;margin-bottom:12px}
.case-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}
.case-tags span{background:var(--light-gray);color:var(--primary);padding:4px 12px;border-radius:20px;font-size:0.85rem}

/* 新闻列表 */
.news-item{border-bottom:1px solid #e2e8f0;padding:24px 0}
.news-date{color:var(--gray);font-size:0.9rem;margin-bottom:8px}
.news-item h3{font-size:1.2rem;margin-bottom:8px}
.news-item p{color:var(--gray);margin-bottom:8px}

/* 联系我们 */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px}
.contact-info h2,.contact-form h2{font-size:1.5rem;margin-bottom:24px}
.info-item{margin-bottom:24px}
.info-item h3{font-size:1.05rem;margin-bottom:4px}
.info-item p{color:var(--gray)}
.form-group{margin-bottom:20px}
.form-group label{display:block;font-weight:600;margin-bottom:6px;font-size:0.95rem}
.form-group input,.form-group textarea{width:100%;padding:12px 16px;border:1px solid #cbd5e1;border-radius:var(--radius);font-size:1rem;transition:border-color 0.3s}
.form-group input:focus,.form-group textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px rgba(26,115,232,0.1)}
.form-group textarea{resize:vertical}

/* 页脚 */
.footer{background:var(--dark);color:#cbd5e1;padding:60px 0 30px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:40px;margin-bottom:40px}
.footer-col h4{color:var(--white);margin-bottom:16px;font-size:1.05rem}
.footer-col p{font-size:0.9rem;margin-bottom:8px}
.footer-col ul li{margin-bottom:8px}
.footer-col ul a{color:#94a3b8;font-size:0.9rem;transition:color 0.3s}
.footer-col ul a:hover{color:var(--white)}
.footer-contact p{font-size:0.9rem;margin-bottom:6px}
.qrcode-placeholder{width:100px;height:100px;background:#334155;display:flex;align-items:center;justify-content:center;border-radius:8px;font-size:0.75rem;color:#94a3b8}
.footer-bottom{border-top:1px solid #334155;padding-top:20px;text-align:center;font-size:0.85rem}
.footer-bottom a{color:#94a3b8}

/* 移动端菜单激活状态 */
.nav.active{display:flex!important;flex-direction:column;position:absolute;top:70px;left:0;right:0;background:var(--white);box-shadow:var(--shadow-lg);padding:20px;z-index:1000}
.menu-toggle.active span:nth-child(1){transform:rotate(45deg) translate(5px,5px)}
.menu-toggle.active span:nth-child(2){opacity:0}
.menu-toggle.active span:nth-child(3){transform:rotate(-45deg) translate(5px,-5px)}

/* 响应式设计 */
@media(max-width:992px){
    .about-grid{grid-template-columns:1fr}
    .contact-grid{grid-template-columns:1fr}
    .footer-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:768px){
    .header .container{height:60px}
    .nav{display:none}
    .menu-toggle{display:flex}
    .nav ul{flex-direction:column;gap:4px}
    .nav a{width:100%}
    .hero{padding:60px 0}
    section{padding:50px 0}
    .footer-grid{grid-template-columns:1fr}
    .case-stats{flex-direction:column;gap:16px}
    .product-grid,.business-grid,.features-grid{grid-template-columns:1fr}
}
@media(min-width:769px){
    .nav{display:block!important}
}