/* ===========================================================
   中数互通（北京）科技有限公司 官网样式系统
   =========================================================== */

:root {
  /* 主色：深蓝科技 */
  --navy-900: #060d1f;
  --navy-800: #0a1530;
  --navy-700: #0f1f45;
  --navy-600: #16305e;
  --navy-500: #1e4079;

  /* 品牌强调色：青蓝 */
  --brand-400: #4da3ff;
  --brand-500: #1f7ae0;
  --brand-600: #1560b8;
  --brand-glow: rgba(77, 163, 255, 0.35);

  /* 辅助色：青绿 */
  --teal-400: #2ed3b7;
  --teal-500: #14a88f;

  /* 中性 */
  --ink-900: #0d1117;
  --ink-700: #2c3444;
  --ink-500: #5a6478;
  --ink-400: #808a9e;
  --line: #e4e8ef;
  --bg-soft: #f6f8fb;
  --bg-white: #ffffff;

  --radius-sm: 6px;
  --radius: 12px;
  --radius-lg: 18px;

  --shadow-sm: 0 1px 3px rgba(13, 17, 23, 0.06);
  --shadow: 0 6px 24px rgba(13, 17, 23, 0.08);
  --shadow-lg: 0 16px 48px rgba(13, 17, 23, 0.12);

  --wrap: 1180px;
  --font: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Helvetica Neue", Arial, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--ink-700);
  background: var(--bg-white);
  line-height: 1.75;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

.wrap { width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }

/* ---------- 顶部导航 ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(6, 13, 31, 0.92);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.logo { display: flex; align-items: center; gap: 10px; color: #fff; }
.logo-img {
  height: 40px; width: auto; display: block;
}
.logo-mark {
  width: 34px; height: 34px; border-radius: 9px; flex: none;
  background: linear-gradient(135deg, var(--brand-400), var(--teal-400));
  display: grid; place-items: center;
  font-weight: 700; font-size: 15px; color: var(--navy-900);
  letter-spacing: -0.5px;
}
.logo-text { font-size: 16px; font-weight: 600; letter-spacing: 0.5px; }
.logo-sub { font-size: 10px; color: rgba(255,255,255,0.45); letter-spacing: 2px; margin-top: -4px; }

.nav-menu { display: flex; align-items: center; gap: 4px; }
.nav-menu a {
  color: rgba(255, 255, 255, 0.72);
  font-size: 14px; padding: 8px 14px; border-radius: var(--radius-sm);
  transition: all 0.2s; white-space: nowrap;
}
.nav-menu a:hover { color: #fff; background: rgba(255, 255, 255, 0.08); }
.nav-menu a.active { color: #fff; background: rgba(77, 163, 255, 0.18); }

.nav-cta {
  background: var(--brand-500) !important; color: #fff !important;
  font-weight: 500; padding: 8px 18px !important;
}
.nav-cta:hover { background: var(--brand-400) !important; }
.nav-cta.on {
  background: var(--brand-400) !important;
  box-shadow: 0 0 0 2px rgba(77, 163, 255, 0.28);
}

.nav-toggle {
  display: none; background: none; border: 0; cursor: pointer;
  width: 40px; height: 40px; padding: 8px;
}
.nav-toggle span {
  display: block; height: 2px; background: #fff; margin: 5px 0;
  border-radius: 2px; transition: 0.3s;
}

/* ---------- 通用区块 ---------- */
.sec { padding: 84px 0; }
.sec-soft { background: var(--bg-soft); }
.sec-dark { background: var(--navy-900); color: rgba(255,255,255,0.75); }

.sec-head { margin-bottom: 48px; }
.sec-tag {
  display: inline-block; font-size: 12px; font-weight: 600;
  letter-spacing: 1.6px; text-transform: uppercase;
  color: var(--brand-500); margin-bottom: 12px;
}
.sec-dark .sec-tag { color: var(--brand-400); }
.sec-title {
  font-size: 30px; font-weight: 600; color: var(--ink-900);
  line-height: 1.4; letter-spacing: -0.3px;
}
.sec-dark .sec-title { color: #fff; }
.sec-desc {
  font-size: 15px; color: var(--ink-500); max-width: 720px; margin-top: 14px;
}
.sec-dark .sec-desc { color: rgba(255,255,255,0.6); }
.sec-head.center { text-align: center; }
.sec-head.center .sec-desc { margin-left: auto; margin-right: auto; }

/* ---------- Hero ---------- */
.hero {
  background: var(--navy-900);
  color: #fff; padding: 96px 0 88px;
  position: relative; overflow: hidden;
}
.hero::before {
  content: ""; position: absolute; top: -180px; right: -120px;
  width: 620px; height: 620px; border-radius: 50%;
  background: radial-gradient(circle, rgba(31,122,224,0.28), transparent 68%);
}
.hero::after {
  content: ""; position: absolute; bottom: -240px; left: -100px;
  width: 520px; height: 520px; border-radius: 50%;
  background: radial-gradient(circle, rgba(46,211,183,0.16), transparent 70%);
}
.hero .wrap { position: relative; z-index: 2; }
.hero-eyebrow {
  display: inline-block; font-size: 12px; letter-spacing: 1.8px;
  color: var(--brand-400); border: 1px solid rgba(77,163,255,0.35);
  padding: 5px 14px; border-radius: 100px; margin-bottom: 24px;
}
.hero h1 {
  font-size: 40px; font-weight: 600; line-height: 1.35;
  letter-spacing: -0.5px; max-width: 860px;
}
.hero h1 em {
  font-style: normal;
  background: linear-gradient(100deg, var(--brand-400), var(--teal-400));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p {
  font-size: 16px; color: rgba(255,255,255,0.62);
  max-width: 680px; margin-top: 22px; line-height: 1.85;
}
.hero-btns { display: flex; gap: 14px; margin-top: 38px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 28px; border-radius: var(--radius-sm);
  font-size: 15px; font-weight: 500; cursor: pointer;
  border: 1px solid transparent; transition: all 0.22s;
}
.btn-primary { background: var(--brand-500); color: #fff; }
.btn-primary:hover { background: var(--brand-400); transform: translateY(-1px); }
.btn-ghost {
  border-color: rgba(255,255,255,0.25); color: #fff; background: transparent;
}
.btn-ghost:hover { border-color: rgba(255,255,255,0.55); background: rgba(255,255,255,0.06); }
.btn-outline { border-color: var(--line); color: var(--ink-700); background: #fff; }
.btn-outline:hover { border-color: var(--brand-500); color: var(--brand-500); }

.hero-stats {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px;
  margin-top: 64px; background: rgba(255,255,255,0.1);
  border-radius: var(--radius); overflow: hidden;
}
.hero-stat { background: rgba(255,255,255,0.03); padding: 24px 20px; }
.hero-stat b {
  display: block; font-size: 24px; font-weight: 600; color: #fff;
  letter-spacing: -0.3px;
}
.hero-stat span { font-size: 13px; color: rgba(255,255,255,0.5); }

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 22px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 32px 28px;
  transition: all 0.25s; position: relative; overflow: hidden;
}
.card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--brand-500), var(--teal-400));
  transform: scaleX(0); transform-origin: left; transition: transform 0.3s;
}
.card:hover { box-shadow: var(--shadow); border-color: transparent; transform: translateY(-3px); }
.card:hover::before { transform: scaleX(1); }
.card-num {
  font-size: 12px; font-weight: 600; letter-spacing: 1.4px;
  color: var(--brand-500); margin-bottom: 14px;
}
.card h3 {
  font-size: 19px; font-weight: 600; color: var(--ink-900);
  margin-bottom: 12px; line-height: 1.5;
}
.card p { font-size: 14px; color: var(--ink-500); line-height: 1.8; }
.card-link {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 14px; font-weight: 500; color: var(--brand-500);
  margin-top: 20px;
}
.card-link:hover { gap: 10px; }

/* 业务大卡片 */
.biz-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg);
  padding: 36px 32px; display: flex; flex-direction: column;
  transition: all 0.28s;
}
.biz-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-4px); border-color: transparent; }
.biz-icon {
  width: 52px; height: 52px; border-radius: 14px; margin-bottom: 22px;
  display: grid; place-items: center; font-size: 22px; font-weight: 700;
}
.biz-icon.b1 { background: rgba(31,122,224,0.1); color: var(--brand-600); }
.biz-icon.b2 { background: rgba(46,211,183,0.12); color: var(--teal-500); }
.biz-icon.b3 { background: rgba(186,117,23,0.1); color: #a06811; }
.biz-card h3 { font-size: 21px; font-weight: 600; color: var(--ink-900); margin-bottom: 8px; }
.biz-sub { font-size: 13px; color: var(--brand-500); font-weight: 500; margin-bottom: 16px; }
.biz-card p { font-size: 14px; color: var(--ink-500); line-height: 1.85; flex: 1; }
.biz-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 22px; }
.tag {
  font-size: 12px; padding: 4px 11px; border-radius: 100px;
  background: var(--bg-soft); color: var(--ink-500);
  border: 1px solid var(--line);
}
.biz-card .card-link { margin-top: 22px; }

/* ---------- 标签式要点 ---------- */
.feat-list { display: grid; gap: 18px; }
.feat-item {
  display: flex; gap: 16px; align-items: flex-start;
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 24px;
  transition: all 0.22s;
}
.feat-item:hover { border-color: var(--brand-400); box-shadow: var(--shadow-sm); }
.feat-idx {
  flex: none; width: 30px; height: 30px; border-radius: 8px;
  background: rgba(31,122,224,0.09); color: var(--brand-600);
  display: grid; place-items: center; font-size: 13px; font-weight: 600;
}
.feat-item h4 { font-size: 16px; font-weight: 600; color: var(--ink-900); margin-bottom: 6px; }
.feat-item p { font-size: 14px; color: var(--ink-500); line-height: 1.8; }

/* ---------- 表格 ---------- */
.tbl-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); }
table { width: 100%; border-collapse: collapse; font-size: 14px; background: #fff; }
th {
  background: var(--bg-soft); text-align: left; padding: 14px 18px;
  font-weight: 600; color: var(--ink-900); font-size: 13px;
  border-bottom: 1px solid var(--line); white-space: nowrap;
}
td { padding: 14px 18px; border-bottom: 1px solid var(--line); color: var(--ink-500); line-height: 1.7; }
tr:last-child td { border-bottom: 0; }
tbody tr:hover td { background: #fafbfd; }

/* ---------- 步骤流程 ---------- */
.steps { display: grid; gap: 0; }
.step {
  display: grid; grid-template-columns: 60px 1fr; gap: 20px;
  padding-bottom: 28px; position: relative;
}
.step:not(:last-child)::before {
  content: ""; position: absolute; left: 22px; top: 46px; bottom: 0;
  width: 1px; background: var(--line);
}
.step-n {
  width: 46px; height: 46px; border-radius: 50%;
  background: #fff; border: 1.5px solid var(--brand-400);
  color: var(--brand-600); display: grid; place-items: center;
  font-size: 15px; font-weight: 600; z-index: 2;
}
.step h4 { font-size: 16px; font-weight: 600; color: var(--ink-900); margin-bottom: 6px; padding-top: 8px; }
.step p { font-size: 14px; color: var(--ink-500); line-height: 1.8; }

/* ---------- 课程列表 ---------- */
.course {
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; padding: 18px 22px; background: #fff;
  border: 1px solid var(--line); border-radius: var(--radius);
  transition: all 0.2s;
}
.course:hover { border-color: var(--brand-400); box-shadow: var(--shadow-sm); }
.course-l { display: flex; align-items: center; gap: 16px; }
.course-ico {
  width: 36px; height: 36px; border-radius: 9px; flex: none;
  background: rgba(31,122,224,0.09); display: grid; place-items: center;
}
.course-ico svg { width: 17px; height: 17px; }
.course h4 { font-size: 15px; font-weight: 500; color: var(--ink-900); }
.course-dur {
  font-size: 13px; color: var(--ink-400); flex: none;
  font-variant-numeric: tabular-nums;
}
.course-meta {
  font-size: 12px; color: var(--ink-400); margin-top: 3px;
}

/* ---------- 师资 ---------- */
.teacher {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 24px; text-align: center;
  transition: all 0.22s;
}
.teacher:hover { border-color: var(--brand-400); box-shadow: var(--shadow-sm); }
.teacher-av {
  width: 58px; height: 58px; border-radius: 50%; margin: 0 auto 14px;
  display: grid; place-items: center; font-size: 20px; font-weight: 600;
  background: linear-gradient(135deg, var(--navy-700), var(--brand-500));
  color: #fff;
}
.teacher h4 { font-size: 16px; font-weight: 600; color: var(--ink-900); margin-bottom: 6px; }
.teacher p { font-size: 13px; color: var(--ink-500); line-height: 1.65; }

/* ---------- 价格卡 ---------- */
.price-box {
  background: linear-gradient(135deg, var(--navy-800), var(--navy-600));
  border-radius: var(--radius-lg); padding: 40px 36px; color: #fff;
}
.price-val { font-size: 40px; font-weight: 600; letter-spacing: -1px; }
.price-val small { font-size: 16px; font-weight: 400; opacity: 0.7; margin-left: 6px; }
.price-list { margin-top: 26px; display: grid; gap: 12px; }
.price-list li {
  display: flex; gap: 10px; font-size: 14px;
  color: rgba(255,255,255,0.75); align-items: flex-start;
}
.price-list li::before {
  content: ""; flex: none; width: 6px; height: 6px; border-radius: 50%;
  background: var(--teal-400); margin-top: 9px;
}

/* ---------- 提示条 ---------- */
.note {
  background: var(--bg-soft); border-left: 3px solid var(--brand-500);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 18px 22px; font-size: 13.5px; color: var(--ink-500); line-height: 1.85;
}
.note strong { color: var(--ink-900); font-weight: 600; }

/* ---------- CTA ---------- */
.cta {
  background: linear-gradient(135deg, var(--navy-900) 0%, var(--navy-700) 100%);
  color: #fff; border-radius: var(--radius-lg);
  padding: 56px 48px; text-align: center;
  position: relative; overflow: hidden;
}
.cta::before {
  content: ""; position: absolute; top: -120px; right: -80px;
  width: 380px; height: 380px; border-radius: 50%;
  background: radial-gradient(circle, rgba(31,122,224,0.3), transparent 70%);
}
.cta > * { position: relative; z-index: 2; }
.cta h2 { font-size: 26px; font-weight: 600; margin-bottom: 12px; }
.cta p { font-size: 15px; color: rgba(255,255,255,0.6); margin-bottom: 30px; }
.cta .btn-primary { padding: 14px 32px; }

/* ---------- 页脚 ---------- */
.footer {
  background: var(--navy-900); color: rgba(255,255,255,0.55);
  padding: 56px 0 28px; font-size: 13.5px;
}
.footer-top {
  display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.4fr;
  gap: 40px; padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.footer h4 {
  font-size: 14px; font-weight: 600; color: #fff; margin-bottom: 18px;
}
.footer li { margin-bottom: 10px; }
.footer a { color: rgba(255,255,255,0.55); transition: color 0.2s; }
.footer a:hover { color: var(--brand-400); }
.footer-brand-desc { margin-top: 16px; line-height: 1.85; max-width: 300px; }
.footer-contact li { display: flex; gap: 10px; line-height: 1.7; }
.footer-contact b { color: rgba(255,255,255,0.8); font-weight: 500; flex: none; }
.footer-bottom {
  padding-top: 24px; display: flex; justify-content: space-between;
  gap: 16px; flex-wrap: wrap; font-size: 12.5px; color: rgba(255,255,255,0.35);
}

/* ---------- 页面头部（子页） ---------- */
.page-head {
  background: var(--navy-900); color: #fff;
  padding: 68px 0 62px; position: relative; overflow: hidden;
}
.page-head::before {
  content: ""; position: absolute; top: -160px; right: -100px;
  width: 480px; height: 480px; border-radius: 50%;
  background: radial-gradient(circle, rgba(31,122,224,0.25), transparent 70%);
}
.page-head .wrap { position: relative; z-index: 2; }
.crumb { font-size: 13px; color: rgba(255,255,255,0.42); margin-bottom: 16px; }
.crumb a:hover { color: var(--brand-400); }
.page-head h1 { font-size: 34px; font-weight: 600; letter-spacing: -0.4px; }
.page-head p {
  font-size: 15px; color: rgba(255,255,255,0.6);
  max-width: 700px; margin-top: 16px; line-height: 1.85;
}
.page-head .biz-tags { margin-top: 26px; }
.page-head .tag {
  background: rgba(255,255,255,0.08); border-color: rgba(255,255,255,0.14);
  color: rgba(255,255,255,0.72);
}

/* ---------- 内容排版 ---------- */
.prose h2 {
  font-size: 22px; font-weight: 600; color: var(--ink-900);
  margin: 44px 0 18px; padding-left: 14px;
  border-left: 3px solid var(--brand-500); line-height: 1.45;
}
.prose h2:first-child { margin-top: 0; }
.prose h3 {
  font-size: 17px; font-weight: 600; color: var(--ink-900);
  margin: 28px 0 12px;
}
.prose p { margin-bottom: 14px; color: var(--ink-500); line-height: 1.9; }
.prose ul { margin: 0 0 16px 0; padding-left: 0; }
.prose ul li {
  position: relative; padding-left: 18px; margin-bottom: 9px;
  color: var(--ink-500); line-height: 1.85;
}
.prose ul li::before {
  content: ""; position: absolute; left: 2px; top: 11px;
  width: 5px; height: 5px; border-radius: 50%; background: var(--brand-400);
}

/* 侧边锚点导航 */
.doc-layout { display: grid; grid-template-columns: 220px 1fr; gap: 56px; align-items: start; }
.doc-nav { position: sticky; top: 92px; }
.doc-nav h5 {
  font-size: 12px; font-weight: 600; letter-spacing: 1.2px;
  color: var(--ink-400); text-transform: uppercase; margin-bottom: 16px;
}
.doc-nav a {
  display: block; font-size: 14px; color: var(--ink-500);
  padding: 9px 14px; border-radius: var(--radius-sm);
  border-left: 2px solid transparent; transition: all 0.2s;
}
.doc-nav a:hover { color: var(--brand-600); background: var(--bg-soft); }
.doc-nav a.on {
  color: var(--brand-600); border-left-color: var(--brand-500);
  background: rgba(31,122,224,0.06); font-weight: 500;
}

/* ---------- 联系方式块 ---------- */
.contact-item {
  display: flex; gap: 16px; padding: 22px;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
}
.contact-ico {
  width: 42px; height: 42px; border-radius: 11px; flex: none;
  background: rgba(31,122,224,0.09); display: grid; place-items: center;
}
.contact-ico svg { width: 19px; height: 19px; }
.contact-item h4 { font-size: 13px; color: var(--ink-400); font-weight: 500; margin-bottom: 5px; }
.contact-item p { font-size: 15px; color: var(--ink-900); font-weight: 500; word-break: break-all; }

/* ---------- 响应式 ---------- */
@media (max-width: 980px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr 1fr; gap: 32px; }
  .doc-layout { grid-template-columns: 1fr; gap: 0; }
  .doc-nav { display: none; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .nav-menu {
    position: fixed; top: 68px; left: 0; right: 0;
    background: var(--navy-900); flex-direction: column;
    align-items: stretch; padding: 12px; gap: 2px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    display: none;
  }
  .nav-menu.open { display: flex; }
  .nav-menu a { padding: 13px 16px; }
  .nav-cta { text-align: center; margin-top: 6px; }
  .nav-toggle { display: block; }

  .sec { padding: 56px 0; }
  .hero { padding: 64px 0 56px; }
  .hero h1 { font-size: 27px; }
  .hero p { font-size: 15px; }
  .sec-title { font-size: 23px; }
  .page-head { padding: 48px 0 44px; }
  .page-head h1 { font-size: 25px; }
  .grid-2, .grid-4 { grid-template-columns: 1fr; }
  .cta { padding: 40px 24px; }
  .cta h2 { font-size: 21px; }
  .card, .biz-card { padding: 26px 22px; }
  .course { flex-direction: column; align-items: flex-start; gap: 10px; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
  .price-box { padding: 30px 24px; }
  .price-val { font-size: 32px; }
}