/* ==========================================================================
   leadingtopunion.cn — 本土化中文站（P1 骨架版）
   品牌视觉复用 .com：主色 #0044d7 / navy #0a2540 / Poppins-Inter 体系
   2026-10-30 首版
   ========================================================================== */

:root {
  --ltu-blue: #0044d7;
  --ltu-blue-hover: #003bbc;
  --ltu-navy: #0a2540;
  --ltu-navy-dark: #061626;
  --ltu-gray: #3e3e3e;
  --ltu-light-bg: #f8fafc;
  --ltu-border: rgba(148, 163, 184, 0.16);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: #ffffff;
  color: var(--ltu-gray);
  overflow-x: hidden;
  max-width: 100vw;
  line-height: 1.7;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Poppins', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  color: #111111;
  line-height: 1.25;
}

::selection { background: var(--ltu-blue); color: #fff; }
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: #f1f1f1; }
::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--ltu-blue); }

a { color: var(--ltu-blue); text-decoration: none; transition: color .2s ease; }
a:hover { color: var(--ltu-blue-hover); }

img, video { max-width: 100%; height: auto; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ---------- 导航 ---------- */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: #fff;
  border-bottom: 1px solid var(--ltu-border);
}
.navbar-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 72px;
}
.brand-name {
  font-family: 'Poppins', sans-serif;
  font-size: 19px; font-weight: 700; color: var(--ltu-navy);
  letter-spacing: -.02em;
}
.brand-name em { font-style: normal; color: var(--ltu-blue); }
.nav-links { display: flex; gap: 22px; align-items: center; }
.nav-links a {
  color: #333; font-size: 14.5px; font-weight: 500; white-space: nowrap;
  padding: 6px 0; border-bottom: 2px solid transparent;
}
.nav-links a:hover, .nav-links a.active { color: var(--ltu-blue); border-bottom-color: var(--ltu-blue); }
.nav-cta {
  background: var(--ltu-blue); color: #fff !important;
  padding: 9px 18px; border-radius: 8px; font-weight: 600; font-size: 13.5px;
}
.nav-cta:hover { background: var(--ltu-blue-hover); }
.nav-toggle {
  display: none; background: none; border: none; font-size: 26px;
  cursor: pointer; color: var(--ltu-navy);
}
@media (max-width: 1260px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute; top: 72px; left: 0; right: 0;
    flex-direction: column; background: #fff; padding: 16px 24px 24px;
    gap: 14px; border-bottom: 1px solid var(--ltu-border); box-shadow: 0 12px 28px rgba(15,23,42,.08);
  }
  .nav-links.open { display: flex; }
  .nav-cta { width: fit-content; }
}

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, var(--ltu-navy-dark) 0%, var(--ltu-navy) 60%, #123a6b 100%);
  color: #fff; padding: 110px 0 90px;
}
.hero h1 {
  color: #fff; font-size: clamp(34px, 5vw, 56px);
  letter-spacing: -.03em; margin-bottom: 22px; font-weight: 700;
}
.hero p { font-size: 18px; line-height: 1.75; color: rgba(255,255,255,.9); max-width: 720px; margin-bottom: 34px; }
.hero-badges { display: flex; flex-wrap: wrap; gap: 10px 26px; margin-bottom: 40px; color: rgba(255,255,255,.85); font-size: 14.5px; }
.hero-badges span::before { content: '✓ '; color: #4ade80; font-weight: 700; }
.hero-cta-row { display: flex; flex-wrap: wrap; gap: 16px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 30px; border-radius: 10px; font-weight: 700; font-size: 15.5px;
  transition: all .2s ease; border: 2px solid transparent;
}
.btn-primary { background: var(--ltu-blue); color: #fff; }
.btn-primary:hover { background: var(--ltu-blue-hover); color: #fff; transform: translateY(-2px); box-shadow: 0 14px 30px rgba(0,68,215,.35); }
.btn-outline { border-color: rgba(255,255,255,.55); color: #fff; }
.btn-outline:hover { background: rgba(255,255,255,.12); color: #fff; }
.btn-outline-blue { border-color: var(--ltu-blue); color: var(--ltu-blue); }
.btn-outline-blue:hover { background: var(--ltu-blue); color: #fff; }

/* ---------- 区块通用 ---------- */
.section { padding: 84px 0; }
.section-alt { background: var(--ltu-light-bg); }
.section-label {
  display: inline-block; color: var(--ltu-blue); font-weight: 700;
  font-size: 13.5px; letter-spacing: .14em; text-transform: uppercase; margin-bottom: 12px;
}
.section-title { font-size: clamp(26px, 3.4vw, 38px); margin-bottom: 14px; font-weight: 700; }
.section-sub { font-size: 16.5px; color: #5a6572; max-width: 780px; margin-bottom: 40px; }
.center { text-align: center; }
.center .section-sub { margin-left: auto; margin-right: auto; }
.title-underline::after {
  content: ''; display: block; width: 60px; height: 3px;
  background: var(--ltu-blue); margin: 16px auto 0;
}

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 28px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 1024px) { .grid-4 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 820px) { .grid-2, .grid-3 { grid-template-columns: 1fr; } }

.card {
  background: #fff; border: 1px solid var(--ltu-border); border-radius: 14px;
  padding: 30px 26px; transition: all .25s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 18px 40px rgba(15,23,42,.08); border-color: rgba(0,68,215,.28); }
.card-icon { width: 54px; height: 54px; border-radius: 12px; background: rgba(0,68,215,.08); display: flex; align-items: center; justify-content: center; margin-bottom: 18px; }
.card-icon svg { width: 26px; height: 26px; fill: var(--ltu-blue); }
.card h3 { font-size: 19px; margin-bottom: 10px; }
.card p { font-size: 14.5px; color: #5a6572; }
.card-link { margin-top: 16px; font-weight: 600; font-size: 14px; }

/* ---------- 数字/承诺条 ---------- */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 28px; }
@media (max-width: 820px) { .stats { grid-template-columns: repeat(2, 1fr); } }
.stat { text-align: center; padding: 34px 16px; }
.stat-num { font-family: 'Poppins', sans-serif; font-size: 40px; font-weight: 700; color: var(--ltu-blue); }
.stat-label { margin-top: 8px; font-size: 14px; color: #5a6572; }

/* ---------- 页脚 ---------- */
.footer { background: var(--ltu-navy-dark); color: rgba(255,255,255,.72); padding: 64px 0 28px; font-size: 14.5px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 44px; }
@media (max-width: 900px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .footer-grid { grid-template-columns: 1fr; } }
.footer h4 { color: #fff; font-size: 16px; margin-bottom: 16px; }
.footer a { color: rgba(255,255,255,.72); }
.footer a:hover { color: #fff; }
.footer ul { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.footer-brand .brand-name { color: #fff; margin-bottom: 12px; display: inline-block; }
.footer-icp { border-top: 1px solid rgba(255,255,255,.12); padding-top: 22px; text-align: center; font-size: 13px; color: rgba(255,255,255,.5); }
.footer-icp a { color: rgba(255,255,255,.65); }

/* ---------- 页面正文 ---------- */
.page-head {
  background: linear-gradient(120deg, var(--ltu-navy) 0%, #123a6b 100%);
  color: #fff; padding: 74px 0 56px;
}
.page-head h1 { color: #fff; font-size: clamp(30px, 4vw, 44px); margin-bottom: 12px; }
.page-head p { color: rgba(255,255,255,.85); font-size: 16.5px; max-width: 720px; }
.crumb { font-size: 13px; color: rgba(255,255,255,.6); margin-bottom: 18px; }
.crumb a { color: rgba(255,255,255,.8); }

.prose { font-size: 16px; }
.prose p { margin-bottom: 18px; }
.prose h2 { font-size: 24px; margin: 40px 0 14px; }
.prose h3 { font-size: 19px; margin: 26px 0 10px; }
.prose ul, .prose ol { margin: 0 0 18px 22px; }
.prose li { margin-bottom: 8px; }

/* 联系与表单 */
.contact-row { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
@media (max-width: 860px) { .contact-row { grid-template-columns: 1fr; } }
.contact-item { display: flex; gap: 16px; align-items: flex-start; margin-bottom: 26px; }
.contact-item .card-icon { margin-bottom: 0; flex: 0 0 auto; }
.contact-item h3 { font-size: 17px; margin-bottom: 4px; }
.contact-item p { font-size: 15px; color: #5a6572; }
.form-group { margin-bottom: 18px; }
.form-group label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; color: #333; }
.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 12px 14px; border: 1px solid var(--ltu-border);
  border-radius: 8px; font-size: 15px; font-family: inherit; color: #333; background: #fff;
}
.form-group input:focus, .form-group textarea:focus { outline: none; border-color: var(--ltu-blue); box-shadow: 0 0 0 3px rgba(0,68,215,.12); }
.form-group textarea { min-height: 140px; resize: vertical; }

/* 案例/知识卡片 */
.meta { font-size: 13px; color: #8893a0; margin-bottom: 10px; }

/* 提醒条 */
.notice {
  background: #fef9ec; border: 1px solid #f2e3b8; color: #7a5b00;
  padding: 14px 18px; border-radius: 10px; font-size: 14px; margin: 24px 0;
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; scroll-behavior: auto !important; }
}
/* 案例卡片配图 */
.case-card img {
  width: 100%; height: 200px; object-fit: cover;
  border-radius: 10px; margin-bottom: 16px; display: block;
}
.case-card h3 { margin-top: 0; }

/* 微信二维码 */
.wechat-qr {
  width: 150px; height: 150px; object-fit: contain;
  border: 1px solid var(--ltu-border); border-radius: 10px;
  margin-top: 10px; background: #fff;
}

/* ---------- 语言切换（中/EN） ---------- */
.nav-links a.lang-switch {
  font-size: 13px; font-weight: 600; color: #64748b;
  border: 1px solid var(--ltu-border); border-radius: 6px;
  padding: 4px 10px; line-height: 1.4;
}
.nav-links a.lang-switch:hover {
  color: var(--ltu-blue); border-color: var(--ltu-blue); border-bottom-color: var(--ltu-blue);
}
@media (max-width: 1260px) {
  .nav-links a.lang-switch { width: fit-content; }
}

/* ---- 产品图与结构示意图（2026-11-05） ---- */
.page-media { margin: 0 0 34px; }
.page-media img { width: 100%; height: auto; border-radius: 14px; display: block; box-shadow: 0 16px 38px rgba(15,23,42,.10); }
.page-media figcaption { margin-top: 10px; font-size: 13px; line-height: 1.7; color: #6b7683; }
.figure-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 22px; margin: 28px 0 6px; }
.figure-grid figure { margin: 0; background: #fff; border: 1px solid rgba(15,23,42,.10); border-radius: 14px; padding: 16px; }
.figure-grid img { width: 100%; height: auto; display: block; }
.figure-grid figcaption { margin-top: 10px; font-size: 13px; line-height: 1.65; color: #475569; }
.card-media { border-radius: 10px; overflow: hidden; margin: 0 0 16px; background: #f3f6fa; aspect-ratio: 4 / 3; }
.card-media img { width: 100%; height: 100%; object-fit: cover; display: block; }