/* ============================================================
   城市分站群 - 公共样式（10 套主题共享）
   - 响应式，移动端优先
   - 颜色由 :root 变量 --primary/--secondary/--accent 注入
   ============================================================ */

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  color:#1f2937;
  background:#fff;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
ul,ol{margin:0;padding:0;list-style:none}
h1,h2,h3,h4{margin:0 0 .5em;line-height:1.3}
p{margin:0 0 1em}
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.container-narrow{max-width:860px}

/* 跳转链接（无障碍） */
.skip-link{position:absolute;left:-9999px;top:0;background:var(--primary);color:#fff;padding:8px 12px;z-index:1000}
.skip-link:focus{left:0}

/* 富文本统一排版 */
.rich{color:#374151}
.rich p{margin:0 0 1em}
.rich img{border-radius:8px;margin:.5em 0}
.rich h2,.rich h3{margin:1em 0 .5em;color:#111827}
.rich ul,.rich ol{margin:0 0 1em 1.2em}
.rich ul{list-style:disc}
.rich ol{list-style:decimal}
.rich a{color:var(--primary);text-decoration:underline}
.rich table{width:100%;border-collapse:collapse;margin:.5em 0}
.rich th,.rich td{border:1px solid #e5e7eb;padding:8px 10px;text-align:left}

/* ============ 顶部导航 ============ */
.site-header{position:sticky;top:0;z-index:100;background:#fff;box-shadow:0 1px 3px rgba(0,0,0,.06)}
.header-inner{display:flex;align-items:center;gap:24px;height:72px}
.brand{display:flex;align-items:center;gap:10px}
.brand-logo{height:42px;width:auto}
.brand-text{display:flex;flex-direction:column;line-height:1.1}
.brand-text strong{font-size:18px;color:#111827}
.brand-text em{font-style:normal;font-size:12px;color:#6b7280}
.main-nav{display:flex;gap:6px;margin-left:auto}
.main-nav a{padding:8px 14px;border-radius:6px;font-size:15px;color:#374151;transition:.2s}
.main-nav a:hover{color:var(--primary);background:color-mix(in srgb,var(--primary) 10%,transparent)}
.cta-phone{display:flex;align-items:center;gap:6px;color:var(--primary);font-weight:600;font-size:15px}
.cta-phone .icon{display:flex}
.nav-toggle{display:none;flex-direction:column;gap:4px;background:none;border:0;cursor:pointer;padding:6px}
.nav-toggle span{width:24px;height:2px;background:#111827;display:block}

/* ============ Hero ============ */
.hero{color:#fff;padding:80px 0;position:relative;overflow:hidden}
.hero-inner{position:relative;z-index:1}
.hero h1{font-size:40px;margin-bottom:16px}
.hero-sub{font-size:18px;max-width:760px;opacity:.95;margin-bottom:24px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap}
.hero-tags{display:flex;flex-wrap:wrap;gap:10px;margin-top:24px}
.hero-tags li{background:rgba(255,255,255,.18);border:1px solid rgba(255,255,255,.35);padding:6px 14px;border-radius:999px;font-size:14px}

/* ============ 通用按钮 ============ */
.btn{display:inline-block;padding:11px 26px;border-radius:6px;font-weight:600;font-size:15px;border:2px solid transparent;transition:.2s;cursor:pointer}
.btn-light{background:#fff;color:var(--primary)}
.btn-light:hover{transform:translateY(-2px);box-shadow:0 6px 18px rgba(0,0,0,.18)}
.btn-outline-light{border-color:rgba(255,255,255,.8);color:#fff;background:rgba(255,255,255,.08)}
.btn-outline-light:hover{background:#fff;color:var(--primary)}

/* ============ 区块 ============ */
.section{padding:64px 0}
.section-alt{background:#f8fafc}
.section-head{text-align:center;margin-bottom:40px}
.section-head .eyebrow{display:inline-block;color:var(--accent);font-size:13px;letter-spacing:2px;font-weight:700;margin-bottom:8px}
.section-head h2{font-size:30px;color:#111827}
.section-head p{color:#6b7280;margin:0}

/* ============ 栅格 ============ */
.grid{display:grid;gap:24px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}

/* ============ 卡片 ============ */
.card{background:#fff;border:1px solid #eef0f3;border-radius:12px;overflow:hidden;transition:.25s}
.card:hover{transform:translateY(-4px);box-shadow:0 14px 30px rgba(0,0,0,.08);border-color:color-mix(in srgb,var(--primary) 30%,#eef0f3)}

/* 服务优势 */
.feature{padding:28px 24px;text-align:center}
.feature-icon{display:inline-flex;width:56px;height:56px;border-radius:50%;background:color-mix(in srgb,var(--primary) 12%,transparent);color:var(--primary);align-items:center;justify-content:center;margin-bottom:14px}
.feature h3{font-size:18px;color:#111827}
.feature p{color:#6b7280;font-size:14px;margin:0}

/* 产品 */
.product-media{aspect-ratio:4/3;background:#f3f4f6;overflow:hidden}
.product-media img{width:100%;height:100%;object-fit:cover;transition:.3s}
.product:hover .product-media img{transform:scale(1.06)}
.product-placeholder{display:flex;height:100%;align-items:center;justify-content:center;color:#cbd5e1}
.product-body{padding:18px 20px}
.product-body h3{font-size:17px;color:#111827}
.product-body .rich{font-size:14px;color:#6b7280}
.product-body .specs{font-size:13px;color:#6b7280;margin:.4em 0 0}
.product-body .price{color:var(--accent);font-weight:700;font-size:16px;margin:.4em 0 0}

/* 服务流程 */
.steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:20px;counter-reset:step}
.step{position:relative;background:#fff;border:1px solid #eef0f3;border-radius:12px;padding:24px 20px;text-align:center}
.step-num{position:absolute;top:-14px;left:50%;transform:translateX(-50%);width:30px;height:30px;border-radius:50%;background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px}
.step-icon{color:var(--accent);display:flex;justify-content:center;margin-bottom:10px}
.step-text h3{font-size:16px}
.step-text p{font-size:13px;color:#6b7280;margin:0}

/* FAQ */
.faq-list{display:flex;flex-direction:column;gap:12px}
.faq-item{background:#fff;border:1px solid #eef0f3;border-radius:10px;overflow:hidden}
.faq-item summary{list-style:none;cursor:pointer;padding:16px 20px;display:flex;justify-content:space-between;align-items:center;font-weight:600;color:#111827}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item[open] summary{color:var(--primary)}
.faq-toggle{font-size:22px;color:var(--accent);transition:.2s}
.faq-item[open] .faq-toggle{transform:rotate(45deg)}
.faq-a{padding:0 20px 16px;color:#4b5563}

/* 联系 */
.contact-grid{align-items:stretch}
.contact-info{background:#fff;border:1px solid #eef0f3;border-radius:12px;padding:28px}
.contact-cta{border-radius:12px;padding:32px;color:#fff;display:flex;flex-direction:column;justify-content:center;gap:10px}
.contact-cta h3{font-size:22px}

/* 其他城市互链 */
.city-chips{display:flex;flex-wrap:wrap;gap:12px;justify-content:center}
.chip{display:inline-block;padding:10px 18px;border-radius:999px;background:#fff;border:1px solid #e5e7eb;color:#374151;transition:.2s}
.chip:hover{background:var(--primary);color:#fff;border-color:var(--primary);transform:translateY(-2px)}

/* 页脚 */
.site-footer{background:#0f172a;color:#cbd5e1;padding:48px 0 0}
.footer-inner{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap;padding-bottom:28px}
.footer-brand strong{color:#fff;font-size:18px}
.footer-nav{display:flex;gap:18px;flex-wrap:wrap}
.footer-nav a:hover{color:#fff}
.copyright{border-top:1px solid rgba(255,255,255,.08);padding:16px 0;font-size:13px;text-align:center}
.copyright a{color:#9ca3af}

/* 返回顶部 */
.back-top{position:fixed;right:24px;bottom:24px;width:44px;height:44px;border-radius:50%;border:0;background:var(--primary);color:#fff;font-size:22px;cursor:pointer;box-shadow:0 6px 18px rgba(0,0,0,.25);opacity:0;visibility:hidden;transition:.3s;z-index:90}
.back-top.show{opacity:1;visibility:visible}

/* Landing / 404 */
body.landing{display:flex;align-items:center;justify-content:center;min-height:100vh;background:#f8fafc}
.landing-inner{text-align:center}
.landing-inner code{background:#eef2ff;padding:2px 8px;border-radius:4px;color:var(--primary)}

/* ============ 响应式 ============ */
@media (max-width:980px){
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .hero h1{font-size:30px}
  .hero-sub{font-size:16px}
}
@media (max-width:768px){
  .header-inner{height:auto;flex-wrap:wrap;padding:10px 0}
  .brand{order:1}
  .nav-toggle{display:flex;order:3}
  .cta-phone{order:2;margin-left:auto;font-size:14px}
  .main-nav{order:4;width:100%;flex-direction:column;display:none;gap:0}
  .main-nav.open{display:flex}
  .main-nav a{padding:12px 0;border-bottom:1px solid #f1f5f9}
  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr}
  .section{padding:44px 0}
  .section-head h2{font-size:24px}
  .hero{padding:48px 0}
}