/* ============================================
   唐山极链网络 - 数字化解决方案服务商
   v1.0 | GEO+SEO Optimized Static Site
   ============================================ */

:root {
  --primary: #2563EB;
  --primary-dark: #1D4ED8;
  --primary-light: #DBEAFE;
  --secondary: #10B981;
  --secondary-dark: #059669;
  --accent: #F59E0B;
  --dark: #0F172A;
  --dark-2: #1E293B;
  --gray-50: #F8FAFC;
  --gray-100: #F1F5F9;
  --gray-200: #E2E8F0;
  --gray-300: #CBD5E1;
  --gray-400: #94A3B8;
  --gray-500: #64748B;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1E293B;
  --white: #FFFFFF;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05);
  --shadow: 0 4px 6px -1px rgba(0,0,0,.1), 0 2px 4px -2px rgba(0,0,0,.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.1), 0 4px 6px -4px rgba(0,0,0,.1);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,.1), 0 8px 10px -6px rgba(0,0,0,.1);
  --radius: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition: .3s cubic-bezier(.4,0,.2,1);
  --max-w: 1200px;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Noto Sans SC","Microsoft YaHei",sans-serif;color:var(--dark);background:var(--white);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%;height:auto;display:block}
ul,ol{list-style:none}

/* Container */
.container{width:100%;max-width:var(--max-w);margin:0 auto;padding:0 24px}

/* Typography */
.section-title{font-size:clamp(1.5rem,3.5vw,2.25rem);font-weight:800;text-align:center;margin-bottom:.5rem}
.section-sub{font-size:clamp(.9rem,2vw,1.1rem);color:var(--gray-500);text-align:center;margin-bottom:3rem;max-width:640px;margin-left:auto;margin-right:auto}
.section-padding{padding:clamp(3rem,6vw,5rem) 0}

/* Buttons */
.btn{display:inline-flex;align-items:center;gap:8px;padding:14px 32px;border-radius:8px;font-weight:600;font-size:1rem;border:none;cursor:pointer;transition:var(--transition);white-space:nowrap}
.btn-primary{background:var(--primary);color:var(--white)}
.btn-primary:hover{background:var(--primary-dark);transform:translateY(-2px);box-shadow:var(--shadow-lg)}
.btn-secondary{background:var(--secondary);color:var(--white)}
.btn-secondary:hover{background:var(--secondary-dark);transform:translateY(-2px);box-shadow:var(--shadow-lg)}
.btn-outline{background:transparent;color:var(--primary);border:2px solid var(--primary)}
.btn-outline:hover{background:var(--primary);color:var(--white);transform:translateY(-2px)}
.btn-white{background:var(--white);color:var(--primary)}
.btn-white:hover{background:var(--gray-100);transform:translateY(-2px)}
.btn-sm{padding:10px 20px;font-size:.875rem}

/* ==================== HEADER ==================== */
.header{position:fixed;top:0;left:0;right:0;z-index:1000;background:rgba(255,255,255,.95);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--gray-200);transition:var(--transition)}
.header.scrolled{box-shadow:var(--shadow)}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:72px}
.logo{display:flex;align-items:center;gap:8px;font-size:1.25rem;font-weight:800;color:var(--dark)}
.logo-icon{width:36px;height:36px;background:linear-gradient(135deg,var(--primary),var(--secondary));border-radius:8px;display:flex;align-items:center;justify-content:center;color:var(--white);font-size:1rem;font-weight:900}
.logo-sub{font-size:.7rem;color:var(--gray-400);font-weight:400;display:block;margin-top:-2px}

.nav{display:flex;align-items:center;gap:32px}
.nav a{font-size:.9rem;font-weight:500;color:var(--gray-600);transition:var(--transition);position:relative;padding:4px 0}
.nav a::after{content:'';position:absolute;bottom:-2px;left:0;width:0;height:2px;background:var(--primary);transition:var(--transition)}
.nav a:hover,.nav a.active{color:var(--primary)}
.nav a:hover::after,.nav a.active::after{width:100%}
.nav .btn{margin-left:8px}

/* Mobile Toggle */
.mobile-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:4px;background:none;border:none}
.mobile-toggle span{display:block;width:24px;height:2px;background:var(--dark);border-radius:2px;transition:var(--transition)}
.mobile-toggle.active span:nth-child(1){transform:rotate(45deg) translate(5px,5px)}
.mobile-toggle.active span:nth-child(2){opacity:0}
.mobile-toggle.active span:nth-child(3){transform:rotate(-45deg) translate(5px,-5px)}

/* ==================== HERO ==================== */
.hero{min-height:100vh;display:flex;align-items:center;position:relative;overflow:hidden;padding-top:72px}
.hero-bg{position:absolute;inset:0;background:linear-gradient(135deg,var(--gray-50) 0%,var(--primary-light) 50%,var(--gray-50) 100%);z-index:0}
.hero-grid{position:absolute;inset:0;background-image:radial-gradient(var(--gray-200) 1px,transparent 1px);background-size:30px 30px;opacity:.4;z-index:0}
.hero-content{position:relative;z-index:1;display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center;padding:80px 0}
.hero-text h1{font-size:clamp(2rem,5vw,3.5rem);font-weight:900;line-height:1.15;margin-bottom:20px}
.hero-text h1 span{background:linear-gradient(135deg,var(--primary),var(--secondary));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-text p{font-size:clamp(1rem,2vw,1.2rem);color:var(--gray-500);line-height:1.7;margin-bottom:32px;max-width:520px}
.hero-btns{display:flex;gap:16px;flex-wrap:wrap}
.hero-visual{position:relative}
.hero-card{background:var(--white);border-radius:var(--radius-xl);padding:40px;box-shadow:var(--shadow-xl);position:relative}
.hero-card-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.hero-card-item{background:var(--gray-50);border-radius:var(--radius);padding:20px;text-align:center;transition:var(--transition)}
.hero-card-item:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.hero-card-item .icon{font-size:2rem;margin-bottom:8px}
.hero-card-item h4{font-size:.9rem;font-weight:600;color:var(--dark)}
.hero-card-item p{font-size:.75rem;color:var(--gray-400);margin-top:4px}
.hero-float{position:absolute;top:-20px;right:-20px;background:var(--secondary);color:var(--white);padding:12px 20px;border-radius:50px;font-size:.85rem;font-weight:600;box-shadow:var(--shadow-lg);animation:float 3s ease-in-out infinite}

@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-8px)}}

/* Stats */
.stats{display:flex;gap:40px;margin-top:40px;padding-top:32px;border-top:1px solid var(--gray-200)}
.stat-item h3{font-size:1.75rem;font-weight:800;color:var(--primary)}
.stat-item p{font-size:.8rem;color:var(--gray-400);margin-top:2px}

/* ==================== SERVICES ==================== */
.services-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:24px}
.service-card{background:var(--white);border:1px solid var(--gray-200);border-radius:var(--radius-lg);padding:32px;transition:var(--transition);position:relative;overflow:hidden}
.service-card::before{content:'';position:absolute;top:0;left:0;right:0;height:4px;background:linear-gradient(90deg,var(--primary),var(--secondary));transform:scaleX(0);transform-origin:left;transition:var(--transition)}
.service-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-xl);border-color:transparent}
.service-card:hover::before{transform:scaleX(1)}
.service-icon{width:56px;height:56px;border-radius:14px;display:flex;align-items:center;justify-content:center;font-size:1.5rem;margin-bottom:20px}
.service-icon.blue{background:var(--primary-light);color:var(--primary)}
.service-icon.green{background:#D1FAE5;color:var(--secondary)}
.service-icon.amber{background:#FEF3C7;color:var(--accent)}
.service-icon.purple{background:#EDE9FE;color:#7C3AED}
.service-card h3{font-size:1.2rem;font-weight:700;margin-bottom:10px}
.service-card p{font-size:.9rem;color:var(--gray-500);line-height:1.7;margin-bottom:16px}
.service-link{color:var(--primary);font-weight:600;font-size:.9rem;display:inline-flex;align-items:center;gap:4px;transition:var(--transition)}
.service-link:hover{gap:8px}

/* ==================== WHY US ==================== */
.why-section{background:var(--gray-50)}
.why-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:24px}
.why-card{background:var(--white);border-radius:var(--radius);padding:28px;box-shadow:var(--shadow-sm);transition:var(--transition)}
.why-card:hover{box-shadow:var(--shadow);transform:translateY(-2px)}
.why-number{font-size:2.5rem;font-weight:900;color:var(--primary-light);line-height:1;margin-bottom:8px}
.why-card h4{font-size:1rem;font-weight:700;margin-bottom:8px}
.why-card p{font-size:.875rem;color:var(--gray-500);line-height:1.6}

/* ==================== PROCESS ==================== */
.process-steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:32px;position:relative}
.process-step{text-align:center;position:relative}
.process-number{width:48px;height:48px;border-radius:50%;background:var(--primary);color:var(--white);display:flex;align-items:center;justify-content:center;font-weight:800;font-size:1.2rem;margin:0 auto 16px;position:relative;z-index:2}
.process-step h4{font-size:1rem;font-weight:700;margin-bottom:8px}
.process-step p{font-size:.85rem;color:var(--gray-500);line-height:1.6}

/* ==================== NEWS / BLOG ==================== */
.news-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:24px}
.news-card{background:var(--white);border:1px solid var(--gray-200);border-radius:var(--radius-lg);overflow:hidden;transition:var(--transition)}
.news-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-xl);border-color:transparent}
.news-content{padding:24px}
.news-tag{display:inline-block;padding:4px 12px;border-radius:50px;font-size:.75rem;font-weight:600;margin-bottom:12px}
.news-tag.blue{background:var(--primary-light);color:var(--primary)}
.news-tag.green{background:#D1FAE5;color:var(--secondary)}
.news-tag.amber{background:#FEF3C7;color:var(--accent)}
.news-card h3{font-size:1.1rem;font-weight:700;margin-bottom:10px;line-height:1.4}
.news-card p{font-size:.85rem;color:var(--gray-500);line-height:1.7;margin-bottom:16px}
.news-meta{font-size:.8rem;color:var(--gray-400);display:flex;gap:16px}

/* ==================== CASES ==================== */
.case-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:24px}
.case-card{background:var(--white);border:1px solid var(--gray-200);border-radius:var(--radius-lg);overflow:hidden;transition:var(--transition)}
.case-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-xl)}
.case-img{height:200px;background:linear-gradient(135deg,var(--primary-light),var(--gray-100));display:flex;align-items:center;justify-content:center;font-size:2.5rem}
.case-body{padding:24px}
.case-body h3{font-size:1.1rem;font-weight:700;margin-bottom:8px}
.case-body p{font-size:.85rem;color:var(--gray-500);line-height:1.6}
.case-tags{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}
.case-tags span{padding:4px 10px;border-radius:50px;font-size:.75rem;background:var(--gray-100);color:var(--gray-600)}

/* ==================== FAQ (GEO Focus) ==================== */
.faq-list{max-width:800px;margin:0 auto}
.faq-item{border:1px solid var(--gray-200);border-radius:var(--radius);margin-bottom:12px;overflow:hidden;transition:var(--transition)}
.faq-item.active{border-color:var(--primary)}
.faq-q{display:flex;justify-content:space-between;align-items:center;padding:20px 24px;cursor:pointer;font-weight:600;font-size:1rem;transition:var(--transition);background:var(--white)}
.faq-q:hover{background:var(--gray-50)}
.faq-q .arrow{transition:var(--transition);font-size:1.2rem;color:var(--gray-400)}
.faq-item.active .faq-q{color:var(--primary)}
.faq-item.active .faq-q .arrow{transform:rotate(180deg);color:var(--primary)}
.faq-a{padding:0 24px;max-height:0;overflow:hidden;transition:var(--transition);color:var(--gray-600);line-height:1.7;font-size:.9rem}
.faq-item.active .faq-a{max-height:500px;padding:0 24px 20px}

/* ==================== CTA ==================== */
.cta-section{background:linear-gradient(135deg,var(--primary),var(--primary-dark));padding:clamp(3rem,5vw,5rem) 0;text-align:center;color:var(--white)}
.cta-section h2{font-size:clamp(1.5rem,3vw,2.25rem);font-weight:800;margin-bottom:16px}
.cta-section p{font-size:1rem;opacity:.9;margin-bottom:32px;max-width:600px;margin-left:auto;margin-right:auto}
.cta-btns{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}

/* ==================== FOOTER ==================== */
.footer{background:var(--dark);color:var(--gray-400);padding:60px 0 32px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:40px;margin-bottom:40px}
.footer-brand .logo{color:var(--white);margin-bottom:16px}
.footer-brand p{font-size:.85rem;line-height:1.7}
.footer h4{color:var(--white);font-size:.95rem;font-weight:700;margin-bottom:16px}
.footer ul li{margin-bottom:8px}
.footer ul a{font-size:.85rem;transition:var(--transition)}
.footer ul a:hover{color:var(--white)}
.footer-bottom{border-top:1px solid var(--gray-700);padding-top:24px;display:flex;justify-content:space-between;align-items:center;font-size:.8rem;flex-wrap:wrap;gap:12px}

/* ==================== PAGE HEADER ==================== */
.page-header{background:linear-gradient(135deg,var(--gray-50),var(--primary-light));padding:140px 0 60px;text-align:center}
.page-header h1{font-size:clamp(1.75rem,4vw,2.75rem);font-weight:900;margin-bottom:12px}
.page-header p{font-size:1rem;color:var(--gray-500);max-width:600px;margin:0 auto}
.breadcrumb{font-size:.85rem;color:var(--gray-400);margin-bottom:16px}
.breadcrumb a{color:var(--primary)}
.breadcrumb span{margin:0 8px}

/* ==================== ARTICLE ==================== */
.article{max-width:800px;margin:0 auto;padding:60px 24px}
.article h1{font-size:clamp(1.75rem,3.5vw,2.5rem);font-weight:900;margin-bottom:16px;line-height:1.3}
.article .meta{color:var(--gray-400);font-size:.9rem;margin-bottom:32px;display:flex;gap:16px;flex-wrap:wrap}
.article .abstract{background:var(--primary-light);border-left:4px solid var(--primary);padding:20px 24px;border-radius:0 var(--radius) var(--radius) 0;margin-bottom:32px;font-size:.95rem;color:var(--gray-700);line-height:1.7}
.article .toc{background:var(--gray-50);border-radius:var(--radius);padding:24px;margin-bottom:32px}
.article .toc h3{font-size:1rem;font-weight:700;margin-bottom:12px}
.article .toc ol{padding-left:20px}
.article .toc li{margin-bottom:6px;font-size:.9rem}
.article .toc a{color:var(--primary)}
.article .toc a:hover{text-decoration:underline}
.article h2{font-size:1.5rem;font-weight:800;margin:40px 0 16px;padding-top:20px}
.article h3{font-size:1.2rem;font-weight:700;margin:28px 0 12px}
.article p{font-size:.95rem;color:var(--gray-600);line-height:1.8;margin-bottom:16px}
.article ul,.article ol{padding-left:24px;margin-bottom:16px}
.article ul li,.article ol li{font-size:.95rem;color:var(--gray-600);line-height:1.8;margin-bottom:6px}
.article ul{list-style:disc}
.article ol{list-style:decimal}
.article strong{color:var(--dark)}
.article table{width:100%;border-collapse:collapse;margin:24px 0;font-size:.9rem}
.article table th{background:var(--gray-50);font-weight:700;text-align:left;padding:12px 16px;border:1px solid var(--gray-200)}
.article table td{padding:12px 16px;border:1px solid var(--gray-200);color:var(--gray-600)}
.article table tr:hover td{background:var(--gray-50)}
.article .faq-block{margin:32px 0}
.article .faq-block h2{margin-top:0}
.article .faq-q-item{margin-bottom:20px}
.article .faq-q-item h4{font-size:1rem;font-weight:700;color:var(--primary);margin-bottom:8px}
.article .faq-q-item p{font-size:.9rem;color:var(--gray-600);margin-bottom:0}
.article .cta-box{background:linear-gradient(135deg,var(--primary),var(--primary-dark));color:var(--white);border-radius:var(--radius-lg);padding:32px;text-align:center;margin:40px 0}
.article .cta-box h3{color:var(--white);font-size:1.2rem;margin-bottom:8px}
.article .cta-box p{color:rgba(255,255,255,.9);margin-bottom:20px}
.article .cta-box .btn-white:hover{background:var(--gray-100)}

/* ==================== CONTACT PAGE ==================== */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:start}
.contact-info h2{font-size:1.5rem;font-weight:800;margin-bottom:16px}
.contact-info>p{color:var(--gray-500);margin-bottom:32px}
.contact-item{display:flex;gap:16px;margin-bottom:24px}
.contact-icon{width:48px;height:48px;background:var(--primary-light);border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:1.2rem;flex-shrink:0}
.contact-item h4{font-size:.9rem;font-weight:600;margin-bottom:4px}
.contact-item p{font-size:.85rem;color:var(--gray-500)}
.contact-form{background:var(--white);border:1px solid var(--gray-200);border-radius:var(--radius-lg);padding:32px}
.contact-form h3{font-size:1.2rem;font-weight:700;margin-bottom:24px}
.form-group{margin-bottom:20px}
.form-group label{display:block;font-size:.85rem;font-weight:600;margin-bottom:6px;color:var(--gray-700)}
.form-group input,.form-group select,.form-group textarea{width:100%;padding:12px 16px;border:1px solid var(--gray-200);border-radius:8px;font-size:.9rem;font-family:inherit;transition:var(--transition);background:var(--white);color:var(--dark)}
.form-group input:focus,.form-group select:focus,.form-group textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-light)}
.form-group textarea{resize:vertical;min-height:120px}

/* ==================== ABOUT ==================== */
.about-mission{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.about-mission h2{font-size:1.5rem;font-weight:800;margin-bottom:16px}
.about-mission p{color:var(--gray-500);line-height:1.7;margin-bottom:16px}
.about-values{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:24px;margin-top:40px}
.value-card{text-align:center;padding:24px;background:var(--gray-50);border-radius:var(--radius)}
.value-card .icon{font-size:2rem;margin-bottom:12px}
.value-card h4{font-size:1rem;font-weight:700;margin-bottom:8px}
.value-card p{font-size:.85rem;color:var(--gray-500)}

/* ==================== RESPONSIVE ==================== */
@media(max-width:968px){
  .hero-content{grid-template-columns:1fr;gap:40px;padding:40px 0}
  .hero-text{text-align:center}
  .hero-text p{margin-left:auto;margin-right:auto}
  .hero-btns{justify-content:center}
  .stats{justify-content:center}
  .footer-grid{grid-template-columns:1fr 1fr}
  .contact-grid{grid-template-columns:1fr}
  .about-mission{grid-template-columns:1fr}
}

@media(max-width:768px){
  .nav{display:none;position:fixed;top:72px;left:0;right:0;background:var(--white);border-bottom:1px solid var(--gray-200);padding:16px 24px;flex-direction:column;gap:16px;z-index:999}
  .nav.open{display:flex}
  .nav .btn{width:100%;justify-content:center}
  .mobile-toggle{display:flex}
  .stats{gap:24px;flex-wrap:wrap}
  .hero-float{display:none}
  .footer-grid{grid-template-columns:1fr}
  .footer-bottom{flex-direction:column;text-align:center}
  .contact-form{padding:20px}
  .contact-item{gap:12px}
  .contact-item .contact-icon{width:40px;height:40px;font-size:1rem;flex-shrink:0}
  .contact-item p{word-break:break-all;font-size:.8rem}
  .contact-item h4{font-size:.85rem}
  .contact-info h2{font-size:1.2rem}
  .contact-info>p{font-size:.85rem}
  .form-group input,.form-group select,.form-group textarea{font-size:.9rem;padding:10px 12px}
}

@media(max-width:480px){
  .hero-btns{flex-direction:column;align-items:center}
  .hero-btns .btn{width:100%;justify-content:center}
  .services-grid{grid-template-columns:1fr}
  .news-grid{grid-template-columns:1fr}
  .case-grid{grid-template-columns:1fr}
  .contact-item{flex-direction:column;align-items:flex-start;gap:8px;margin-bottom:20px}
  .contact-form{padding:16px}
  .contact-info h2{font-size:1.1rem}
}

/* ==================== ANIMATIONS ==================== */
.fade-in{opacity:0;transform:translateY(24px);transition:opacity .6s ease,transform .6s ease}
.fade-in.visible{opacity:1;transform:translateY(0)}