/* ===== 基础重置 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --primary: #0b5fff;
  --primary-dark: #0946b8;
  --dark: #0d1b2e;
  --text: #333;
  --text-light: #666;
  --bg-gray: #f5f7fa;
}

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  color: var(--text);
  line-height: 1.7;
}

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

.container {
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== 顶部导航 ===== */
.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: transparent;
  transition: background .3s, box-shadow .3s;
}

.header.scrolled {
  background: #fff;
  box-shadow: 0 2px 12px rgba(0,0,0,.08);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.logo-mark {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 2px;
}

.logo-sub {
  font-size: 11px;
  color: #999;
  letter-spacing: 3px;
}

.nav { display: flex; gap: 36px; }

.nav-link {
  font-size: 15px;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: color .2s, border-color .2s;
}

.nav-link:hover,
.nav-link.active { color: var(--primary); border-color: var(--primary); }

.header.scrolled .logo-mark { color: var(--dark); }
.header:not(.scrolled) .nav-link { color: #fff; }
.header.scrolled .nav-link { color: var(--text); }
.header:not(.scrolled) .nav-link:hover,
.header:not(.scrolled) .nav-link.active { color: #fff; border-color: #fff; }

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
}

.menu-toggle span {
  width: 24px; height: 2px;
  background: #fff;
  transition: background .3s;
}

.header.scrolled .menu-toggle span { background: var(--dark); }

/* ===== 首屏 ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  background: linear-gradient(135deg, #0b2a6b 0%, #0b5fff 55%, #29a3ff 100%);
  color: #fff;
  text-align: center;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 30%, rgba(255,255,255,.12), transparent 45%),
    radial-gradient(ellipse at 80% 70%, rgba(0,0,0,.18), transparent 50%);
}

.hero-content { position: relative; z-index: 1; }

.hero-title {
  font-size: 52px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 24px;
  letter-spacing: 2px;
}

.hero-desc {
  font-size: 18px;
  opacity: .92;
  margin-bottom: 40px;
}

.hero-btns { display: flex; gap: 16px; justify-content: center; }

.btn {
  display: inline-block;
  padding: 13px 38px;
  font-size: 15px;
  border-radius: 4px;
  transition: all .25s;
}

.btn-primary {
  background: #fff;
  color: var(--primary);
  font-weight: 600;
}

.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 20px rgba(0,0,0,.2); }

.btn-outline {
  border: 1px solid rgba(255,255,255,.7);
  color: #fff;
}

.btn-outline:hover { background: rgba(255,255,255,.15); }

/* ===== 数据概览 ===== */
.stats {
  background: #fff;
  padding: 56px 0;
  box-shadow: 0 4px 16px rgba(0,0,0,.05);
  position: relative;
  z-index: 2;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  text-align: center;
}

.stat-num {
  font-size: 26px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 6px;
}

.stat-label { font-size: 14px; color: var(--text-light); }

/* ===== 通用板块 ===== */
.section { padding: 90px 0; }
.section-gray { background: var(--bg-gray); }
.section-dark {
  background: var(--dark);
  color: #fff;
}

.section-head { text-align: center; margin-bottom: 56px; }

.section-title {
  font-size: 34px;
  font-weight: 700;
  letter-spacing: 2px;
}

.section-line {
  width: 56px; height: 4px;
  background: var(--primary);
  margin: 18px auto 0;
  border-radius: 2px;
}

/* ===== 关于我们 ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 56px;
  align-items: start;
}

.about-text h3 {
  font-size: 22px;
  color: var(--dark);
  margin-bottom: 20px;
}

.about-text p { margin-bottom: 16px; color: var(--text-light); }

.about-list {
  list-style: none;
  margin-top: 24px;
}

.about-list li {
  padding-left: 26px;
  position: relative;
  margin-bottom: 12px;
  color: var(--text);
}

.about-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--primary);
  font-weight: 700;
}

.about-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.info-card {
  background: var(--bg-gray);
  border-radius: 8px;
  padding: 26px 22px;
  transition: transform .25s, box-shadow .25s;
}

.info-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 24px rgba(11,95,255,.12);
}

.info-card h4 {
  color: var(--primary);
  font-size: 16px;
  margin-bottom: 10px;
}

.info-card p { font-size: 14px; color: var(--text-light); }

/* ===== 业务领域 ===== */
.biz-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.biz-card {
  background: #fff;
  border-radius: 10px;
  padding: 40px 30px;
  transition: transform .25s, box-shadow .25s;
  border: 1px solid transparent;
}

.biz-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 14px 32px rgba(0,0,0,.1);
  border-color: rgba(11,95,255,.2);
}

.biz-icon {
  width: 58px; height: 58px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(11,95,255,.12), rgba(41,163,255,.18));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  margin-bottom: 20px;
}

.biz-card h3 {
  font-size: 18px;
  margin-bottom: 12px;
  color: var(--dark);
}

.biz-card p { font-size: 14px; color: var(--text-light); }

/* ===== 核心优势 ===== */
.adv-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.adv-item {
  padding: 32px 26px;
  border-radius: 10px;
  background: var(--bg-gray);
  position: relative;
  overflow: hidden;
  transition: transform .25s, box-shadow .25s;
}

.adv-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 28px rgba(0,0,0,.1);
}

.adv-num {
  font-size: 44px;
  font-weight: 800;
  color: rgba(11,95,255,.14);
  position: absolute;
  top: 12px; right: 18px;
}

.adv-item h3 {
  font-size: 17px;
  color: var(--dark);
  margin-bottom: 12px;
}

.adv-item p { font-size: 14px; color: var(--text-light); }

/* ===== 联系我们 ===== */
.section-dark .section-title { color: #fff; }

.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.contact-item {
  background: rgba(255,255,255,.06);
  border-radius: 10px;
  padding: 32px 26px;
  text-align: center;
  transition: background .25s;
}

.contact-item:hover { background: rgba(255,255,255,.1); }

.contact-item h4 {
  font-size: 15px;
  color: #8fb8ff;
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.contact-item p { font-size: 14px; opacity: .92; }

/* ===== 页脚 ===== */
.footer {
  background: #081222;
  color: rgba(255,255,255,.6);
  padding: 28px 0;
  font-size: 13px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

/* ===== 响应式 ===== */
@media (max-width: 960px) {
  .pc-only { display: none; }
  .hero-title { font-size: 36px; }
  .about-grid { grid-template-columns: 1fr; }
  .biz-grid { grid-template-columns: repeat(2, 1fr); }
  .adv-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 28px; }
}

@media (max-width: 600px) {
  .menu-toggle { display: flex; }

  .nav {
    position: fixed;
    top: 72px;
    left: 0; right: 0;
    background: #fff;
    flex-direction: column;
    gap: 0;
    padding: 8px 0;
    box-shadow: 0 10px 20px rgba(0,0,0,.1);
    transform: translateY(-130%);
    transition: transform .3s;
  }

  .nav.open { transform: translateY(0); }

  .nav-link {
    padding: 14px 24px;
    color: var(--text) !important;
    border-bottom: none;
  }

  .biz-grid,
  .adv-grid,
  .contact-grid { grid-template-columns: 1fr; }

  .hero-title { font-size: 30px; letter-spacing: 1px; }
  .hero-desc { font-size: 15px; }
  .section-title { font-size: 26px; }
  .section { padding: 64px 0; }
}