/* ============================================================
   北京雪界科技有限公司 官网样式
   配色：藏青(Navy) + 琥珀(Amber)
   ============================================================ */

:root {
  --navy-900: #0b1f33;
  --navy-800: #0f2a43;
  --navy-700: #163a5a;
  --navy-600: #1f4a6e;
  --navy-100: #e6edf3;
  --ink: #16222e;
  --muted: #5b6b7a;
  --amber-500: #e0a23b;
  --amber-400: #f0b64c;
  --amber-300: #f7cd7a;
  --bg: #ffffff;
  --bg-alt: #f4f7fa;
  --line: #e2e8ef;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 18px 40px -18px rgba(15, 42, 67, 0.35);
  --shadow-soft: 0 10px 30px -16px rgba(15, 42, 67, 0.28);
  --maxw: 1180px;
  --nav-h: 68px;
  --font: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: var(--nav-h); }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { margin: 0; line-height: 1.25; font-weight: 700; letter-spacing: .5px; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 22px; border-radius: 999px; font-weight: 600; font-size: 15px;
  border: 1px solid transparent; cursor: pointer; transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-lg { padding: 14px 30px; font-size: 16px; }
.btn-block { width: 100%; }
.btn-amber { background: linear-gradient(135deg, var(--amber-400), var(--amber-500)); color: #2a1c05; box-shadow: 0 10px 24px -10px rgba(224,162,59,.7); }
.btn-amber:hover { box-shadow: 0 14px 30px -8px rgba(224,162,59,.85); transform: translateY(-2px); }
.btn-ghost { background: rgba(255,255,255,.08); color: #fff; border-color: rgba(255,255,255,.35); }
.btn-ghost:hover { background: rgba(255,255,255,.16); transform: translateY(-2px); }

/* ---------- 导航 ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; height: var(--nav-h); z-index: 100;
  background: rgba(11, 31, 51, .0); transition: background .3s ease, box-shadow .3s ease;
}
.nav.scrolled { background: rgba(11,31,51,.92); backdrop-filter: blur(10px); box-shadow: 0 6px 24px -12px rgba(0,0,0,.5); }
.nav-inner { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: #fff; font-weight: 700; }
.brand-mark {
  width: 34px; height: 34px; border-radius: 9px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--amber-400), var(--amber-500)); color: #2a1c05; font-weight: 800; font-size: 18px;
}
.brand-text { font-size: 19px; letter-spacing: 1px; }
.brand-accent { color: var(--amber-400); }
.nav-links { display: flex; gap: 26px; margin-left: auto; }
.nav-links a { color: rgba(255,255,255,.86); font-size: 15px; font-weight: 500; position: relative; padding: 6px 0; }
.nav-links a::after { content: ""; position: absolute; left: 0; bottom: 0; height: 2px; width: 0; background: var(--amber-400); transition: width .25s ease; }
.nav-links a:hover { color: #fff; }
.nav-links a:hover::after { width: 100%; }
.nav-cta { margin-left: 8px; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 24px; height: 2px; background: #fff; border-radius: 2px; transition: .25s; }

/* ---------- Hero ---------- */
.hero { position: relative; min-height: 100vh; display: flex; align-items: center; overflow: hidden;
  background: radial-gradient(120% 120% at 80% 0%, #163a5a 0%, #0f2a43 45%, #0b1f33 100%); }
.hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; }
.hero-overlay { position: absolute; inset: 0; z-index: 1;
  background: linear-gradient(180deg, rgba(11,31,51,.2) 0%, rgba(11,31,51,.55) 100%); }
.hero-content { position: relative; z-index: 2; color: #fff; padding-top: var(--nav-h); }
.hero-eyebrow { color: var(--amber-300); font-size: 14px; letter-spacing: 2px; margin: 0 0 18px; font-weight: 600; }
.hero-title { font-size: clamp(34px, 6vw, 62px); font-weight: 800; letter-spacing: 1px; margin: 0 0 20px; }
.hero-title .hl { color: var(--amber-400); }
.hero-sub { font-size: clamp(16px, 2.2vw, 20px); color: rgba(255,255,255,.82); margin: 0 0 34px; max-width: 620px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 54px; }
.hero-stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; max-width: 820px; }
.stat { border-left: 2px solid rgba(240,182,76,.55); padding-left: 16px; }
.stat-num { font-size: clamp(26px, 4vw, 40px); font-weight: 800; color: #fff; line-height: 1.1; }
.stat-label { font-size: 14px; color: rgba(255,255,255,.7); margin-top: 4px; }
.scroll-hint { position: absolute; left: 50%; bottom: 22px; transform: translateX(-50%); z-index: 3;
  color: rgba(255,255,255,.7); font-size: 28px; animation: bob 1.8s ease-in-out infinite; }
@keyframes bob { 0%,100%{ transform: translate(-50%,0);} 50%{ transform: translate(-50%,8px);} }

/* ---------- 通用 section ---------- */
.section { padding: 96px 0; }
.section-alt { background: var(--bg-alt); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 56px; }
.kicker { display: inline-block; font-size: 13px; letter-spacing: 3px; color: var(--amber-500); font-weight: 700; margin-bottom: 12px; }
.section-title { font-size: clamp(26px, 4vw, 40px); color: var(--navy-800); }
.section-desc { color: var(--muted); margin-top: 14px; font-size: 16px; }

/* ---------- 核心业务卡片 ---------- */
.cards-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 22px; }
.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 30px 24px;
  box-shadow: var(--shadow-soft); transition: transform .22s ease, box-shadow .22s ease, border-color .22s ease;
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow); border-color: rgba(224,162,59,.5); }
.card-icon {
  width: 56px; height: 56px; border-radius: 14px; display: grid; place-items: center; font-size: 28px;
  background: linear-gradient(135deg, #eaf1f7, #dbe7f1); margin-bottom: 18px;
}
.card h3 { font-size: 20px; color: var(--navy-800); margin-bottom: 10px; }
.card p { color: var(--muted); font-size: 14.5px; margin: 0 0 16px; }
.card-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.card-list li { font-size: 13.5px; color: var(--navy-700); padding-left: 20px; position: relative; }
.card-list li::before { content: "✓"; position: absolute; left: 0; color: var(--amber-500); font-weight: 700; }

/* ---------- 覆盖区域 ---------- */
.coverage-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.area {
  position: relative; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 22px;
  overflow: hidden; transition: transform .22s ease, box-shadow .22s ease;
}
.area::before { content: ""; position: absolute; left: 0; top: 0; height: 4px; width: 100%; background: linear-gradient(90deg, var(--navy-600), var(--amber-500)); transform: scaleX(0); transform-origin: left; transition: transform .3s ease; }
.area:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.area:hover::before { transform: scaleX(1); }
.area-tag { display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: 1px; color: var(--amber-600, #b9802a);
  background: #fdf3e0; padding: 4px 12px; border-radius: 999px; margin-bottom: 14px; }
.area h3 { font-size: 21px; color: var(--navy-800); margin-bottom: 8px; }
.area p { color: var(--muted); font-size: 14px; margin: 0 0 16px; }
.area-meta { display: flex; gap: 10px; flex-wrap: wrap; }
.area-meta span { font-size: 12.5px; color: var(--navy-700); background: var(--bg-alt); border-radius: 8px; padding: 4px 10px; }
.coverage-note { text-align: center; color: var(--muted); font-size: 13px; margin-top: 28px; }

/* ---------- 优势 ---------- */
.adv-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.adv { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; transition: transform .22s ease, box-shadow .22s ease; }
.adv:hover { transform: translateY(-5px); box-shadow: var(--shadow-soft); }
.adv-ic { width: 50px; height: 50px; border-radius: 12px; display: grid; place-items: center; font-size: 24px;
  background: linear-gradient(135deg, var(--navy-700), var(--navy-600)); margin-bottom: 16px; }
.adv h3 { font-size: 18px; color: var(--navy-800); margin-bottom: 8px; }
.adv p { color: var(--muted); font-size: 14.5px; margin: 0; }

/* ---------- 合作伙伴 ---------- */
.partners-grid { display: grid; grid-template-columns: repeat(6, 1fr); gap: 16px; }
.partner {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-sm); height: 92px;
  display: grid; place-items: center; color: var(--navy-700); font-weight: 700; font-size: 15px; letter-spacing: .5px;
  transition: transform .2s ease, border-color .2s ease; text-align: center; padding: 8px;
}
.partner:hover { transform: translateY(-4px); border-color: rgba(224,162,59,.6); color: var(--navy-800); }

/* ---------- 联系 ---------- */
.contact { background: radial-gradient(120% 120% at 15% 0%, #163a5a 0%, #0f2a43 55%, #0b1f33 100%); color: #fff; }
.contact .kicker { color: var(--amber-400); }
.contact .section-title { color: #fff; }
.contact .section-desc { color: rgba(255,255,255,.78); }
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: start; }
.contact-list { list-style: none; padding: 0; margin: 28px 0 0; display: grid; gap: 20px; }
.contact-list li { display: flex; gap: 14px; align-items: flex-start; }
.ci { font-size: 22px; line-height: 1.4; }
.contact-list strong { display: block; font-size: 15px; margin-bottom: 2px; }
.contact-list div { color: rgba(255,255,255,.8); font-size: 14px; }

.wecom-box { margin-top: 26px; display: flex; gap: 16px; align-items: center; flex-wrap: wrap; }
.wecom-qr {
  width: 118px; height: 118px; border-radius: 12px; background: #fff; color: var(--navy-700);
  display: grid; place-items: center; text-align: center; font-size: 12.5px; line-height: 1.5; font-weight: 600;
  border: 2px dashed rgba(224,162,59,.75); padding: 10px; flex: 0 0 auto;
}
.wecom-qr img { width: 100%; height: 100%; object-fit: contain; border-radius: 8px; }
.wecom-tip { flex: 1; min-width: 190px; font-size: 12.5px; color: rgba(255,255,255,.6); margin: 0; line-height: 1.6; }

.contact-form { background: #fff; border-radius: var(--radius); padding: 30px; color: var(--ink); box-shadow: var(--shadow); }
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 13.5px; font-weight: 600; color: var(--navy-800); margin-bottom: 6px; }
.field input, .field select, .field textarea {
  width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: var(--radius-sm);
  font-size: 15px; font-family: inherit; color: var(--ink); background: #fff; transition: border-color .18s, box-shadow .18s;
}
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none; border-color: var(--amber-500); box-shadow: 0 0 0 3px rgba(224,162,59,.18);
}
.field textarea { resize: vertical; }
.field .err { display: block; color: #c0392b; font-size: 12.5px; min-height: 14px; margin-top: 4px; }
.field.invalid input, .field.invalid select { border-color: #c0392b; }
.form-note { margin: 14px 0 0; padding: 12px 14px; border-radius: var(--radius-sm); font-size: 14px; font-weight: 600; }
.form-note.ok { background: #eaf7ee; color: #1d7a43; }
.form-note.bad { background: #fdecea; color: #c0392b; }

/* ---------- 页脚 ---------- */
.footer { background: var(--navy-900); color: rgba(255,255,255,.78); padding-top: 56px; }
.footer-inner { display: grid; grid-template-columns: 1.4fr 2fr; gap: 40px; padding-bottom: 40px; }
.footer .brand { color: #fff; margin-bottom: 14px; }
.footer-desc { font-size: 14px; max-width: 360px; color: rgba(255,255,255,.66); }
.footer-cols { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.footer-cols h4 { color: #fff; font-size: 15px; margin-bottom: 14px; }
.footer-cols a { display: block; font-size: 14px; color: rgba(255,255,255,.7); padding: 5px 0; transition: color .18s; }
.footer-cols a:hover { color: var(--amber-400); }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.1); padding: 18px 0; font-size: 13px; color: rgba(255,255,255,.6); }
.footer-bottom .container { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.footer-bottom .icp { color: rgba(255,255,255,.5); }

/* ---------- 滚动揭示动画 ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- 响应式 ---------- */
@media (max-width: 980px) {
  .cards-grid { grid-template-columns: repeat(3, 1fr); }
  .coverage-grid { grid-template-columns: repeat(2, 1fr); }
  .adv-grid { grid-template-columns: repeat(2, 1fr); }
  .partners-grid { grid-template-columns: repeat(3, 1fr); }
  .contact-grid { grid-template-columns: 1fr; gap: 32px; }
  .footer-inner { grid-template-columns: 1fr; gap: 28px; }
}
@media (max-width: 720px) {
  .nav-links { position: fixed; inset: var(--nav-h) 0 auto 0; flex-direction: column; gap: 0;
    background: rgba(11,31,51,.97); padding: 10px 22px 18px; transform: translateY(-130%); transition: transform .3s ease; }
  .nav-links.open { transform: translateY(0); }
  .nav-links a { padding: 14px 0; border-bottom: 1px solid rgba(255,255,255,.08); }
  .nav-cta { display: none; }
  .nav-toggle { display: flex; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); gap: 20px 14px; }
  .br-mobile { display: none; }
  .section { padding: 64px 0; }
  .cards-grid, .coverage-grid, .adv-grid, .partners-grid { grid-template-columns: 1fr; }
  .footer-cols { grid-template-columns: 1fr 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}

/* ---------- 常见问题 FAQ ---------- */
.faq-list { max-width: 860px; margin: 0 auto; }
.faq-item { border: 1px solid var(--line); border-radius: var(--radius-sm); margin-bottom: 14px; overflow: hidden; background: var(--bg); transition: box-shadow .2s ease, border-color .2s ease; }
.faq-item.open { border-color: var(--amber-500); box-shadow: var(--shadow-soft); }
.faq-q { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 18px 22px; background: transparent; border: 0; cursor: pointer; font-size: 17px; font-weight: 600; color: var(--ink); text-align: left; font-family: inherit; }
.faq-q:hover { color: var(--navy-700); }
.faq-ic { flex: 0 0 auto; width: 26px; height: 26px; border-radius: 50%; background: var(--bg-alt); color: var(--amber-500); display: grid; place-items: center; font-size: 20px; line-height: 1; transition: transform .25s ease, background .2s ease; }
.faq-item.open .faq-ic { transform: rotate(45deg); background: var(--amber-500); color: #2a1c05; }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .3s ease; }
.faq-a p { margin: 0; padding: 0 22px 20px; color: var(--muted); font-size: 15px; }

/* ---------- 软件工具下载 ---------- */
.dl-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.dl-card { background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 22px; display: flex; flex-direction: column; text-align: center; transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease; }
.dl-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--amber-300); }
.dl-ic { width: 58px; height: 58px; margin: 0 auto 14px; border-radius: 14px; background: linear-gradient(135deg, var(--navy-700), var(--navy-800)); color: var(--amber-400); display: grid; place-items: center; font-size: 28px; }
.dl-card h3 { font-size: 18px; margin-bottom: 8px; }
.dl-card p { color: var(--muted); font-size: 14px; margin: 0 0 16px; flex: 1; }
.dl-meta { display: flex; justify-content: center; gap: 8px; flex-wrap: wrap; margin-bottom: 18px; }
.dl-meta span { font-size: 12px; color: var(--muted); background: var(--bg-alt); border: 1px solid var(--line); border-radius: 999px; padding: 4px 10px; }
.dl-meta .dl-os { color: #2a1c05; background: linear-gradient(135deg, var(--amber-300), var(--amber-500)); border-color: transparent; font-weight: 600; }
.dl-note { text-align: center; color: var(--muted); font-size: 13px; margin-top: 24px; }

/* ---------- 积联码 · 产品主品牌 ---------- */
.brand-en { font-size: .55em; color: var(--amber-500); font-weight: 700; letter-spacing: 1px; vertical-align: middle; margin-left: 8px; }
.jl-panel {
  background: radial-gradient(120% 140% at 85% 0%, #163a5a 0%, #0f2a43 55%, #0b1f33 100%);
  border-radius: var(--radius); padding: 48px; color: #fff; box-shadow: var(--shadow);
  display: grid; grid-template-columns: 1.05fr 1fr; gap: 44px; align-items: center;
}
.jl-slogan { display: flex; align-items: center; gap: 12px; font-size: clamp(22px, 3vw, 30px); font-weight: 800; color: #fff; margin: 0 0 18px; letter-spacing: 1px; }
.jl-slogan i { color: var(--amber-400); font-style: normal; }
.jl-intro { color: rgba(255,255,255,.82); font-size: 16px; margin: 0 0 28px; }
.jl-cta { display: flex; gap: 14px; flex-wrap: wrap; }
.jl-features { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.jl-feat { background: rgba(255,255,255,.06); border: 1px solid rgba(255,255,255,.1); border-radius: var(--radius-sm); padding: 20px; transition: transform .2s ease, border-color .2s ease, background .2s ease; }
.jl-feat:hover { transform: translateY(-4px); border-color: rgba(224,162,59,.6); background: rgba(255,255,255,.09); }
.jl-ic { width: 46px; height: 46px; border-radius: 12px; display: grid; place-items: center; font-size: 22px; background: linear-gradient(135deg, var(--amber-400), var(--amber-500)); margin-bottom: 12px; }
.jl-feat h4 { font-size: 16px; color: #fff; margin-bottom: 6px; }
.jl-feat p { font-size: 13.5px; color: rgba(255,255,255,.72); margin: 0; }
.jl-flow { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 14px; margin-top: 36px; }
.flow-node { background: #fff; border: 1px solid var(--line); border-radius: 999px; padding: 12px 22px; font-weight: 700; color: var(--navy-800); font-size: 15px; box-shadow: var(--shadow-soft); }
.flow-arrow { color: var(--amber-500); font-size: 22px; font-weight: 800; }

/* ---------- 响应式补充 ---------- */
@media (max-width: 980px) {
  .dl-grid { grid-template-columns: repeat(2, 1fr); }
  .jl-panel { grid-template-columns: 1fr; padding: 36px 28px; gap: 30px; }
}
@media (max-width: 560px) {
  .dl-grid { grid-template-columns: 1fr; }
  .faq-q { font-size: 15px; padding: 16px 16px; }
  .jl-features { grid-template-columns: 1fr; }
  .jl-flow { gap: 10px; }
  .flow-node { font-size: 13.5px; padding: 10px 16px; }
  .flow-arrow { font-size: 18px; }
}