/* ===== 全局重置与变量 ===== */
:root {
  --primary: #0a3d7a;
  --primary-light: #1565c0;
  --primary-dark: #06234a;
  --accent: #e65100;
  --accent-light: #ff6d00;
  --text-main: #1a1a2e;
  --text-gray: #555e6e;
  --text-light: #8a92a0;
  --bg-white: #ffffff;
  --bg-light: #f5f7fa;
  --bg-dark: #0a1628;
  --border: #e0e6ef;
  --shadow-sm: 0 2px 8px rgba(10,61,122,0.08);
  --shadow-md: 0 4px 20px rgba(10,61,122,0.12);
  --shadow-lg: 0 8px 40px rgba(10,61,122,0.18);
  --radius: 8px;
  --radius-lg: 16px;
  --transition: 0.3s ease;
  --nav-height: 70px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text-main);
  background: var(--bg-white);
  line-height: 1.7;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ===== 排版 ===== */
.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary-dark);
  text-align: center;
  margin-bottom: 0.5rem;
}
.section-sub {
  font-size: 1rem;
  color: var(--text-gray);
  text-align: center;
  margin-bottom: 3rem;
}
.section-title::after {
  content: '';
  display: block;
  width: 50px;
  height: 3px;
  background: var(--accent);
  margin: 0.6rem auto 0;
  border-radius: 2px;
}

/* ===== 布局容器 ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
section { padding: 80px 0; }
section.bg-light { background: var(--bg-light); }
section.bg-dark { background: var(--bg-dark); color: #fff; }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 4px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: all var(--transition);
  letter-spacing: 0.02em;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-light); transform: translateY(-2px); box-shadow: var(--shadow-md); }
.btn-outline {
  border: 2px solid #fff;
  color: #fff;
}
.btn-outline:hover { background: rgba(255,255,255,0.15); transform: translateY(-2px); }
.btn-blue {
  background: var(--primary);
  color: #fff;
}
.btn-blue:hover { background: var(--primary-light); transform: translateY(-2px); box-shadow: var(--shadow-md); }

/* ===== 顶部导航 ===== */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  z-index: 1000;
  transition: all var(--transition);
  background: transparent;
}
#navbar.scrolled {
  background: var(--bg-white);
  box-shadow: var(--shadow-sm);
}
#navbar.scrolled .nav-logo-text { color: var(--primary-dark); }
#navbar.scrolled .nav-menu a { color: var(--text-main); }
#navbar.scrolled .nav-menu a:hover { color: var(--primary); }
#navbar.scrolled .lang-btn { color: var(--text-gray); border-color: var(--border); }
#navbar.scrolled .lang-btn.active { color: var(--primary); border-color: var(--primary); background: rgba(10,61,122,0.06); }

.nav-inner {
  display: flex;
  align-items: center;
  height: var(--nav-height);
  gap: 2rem;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}
.nav-logo img {
  height: 42px;
  width: auto;
}
.nav-logo-text {
  display: flex;
  flex-direction: column;
  color: #fff;
}
.nav-logo-text span:first-child {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.2;
}
.nav-logo-text span:last-child {
  font-size: 0.7rem;
  opacity: 0.85;
  letter-spacing: 0.05em;
}
.nav-menu {
  display: flex;
  align-items: center;
  gap: 0;
  margin-left: auto;
}
.nav-menu a {
  display: block;
  padding: 0 18px;
  font-size: 0.92rem;
  font-weight: 500;
  color: rgba(255,255,255,0.92);
  line-height: var(--nav-height);
  position: relative;
  transition: color var(--transition);
}
.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 12px;
  left: 18px; right: 18px;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transition: transform var(--transition);
}
.nav-menu a:hover::after, .nav-menu a.active::after { transform: scaleX(1); }
.nav-menu a:hover { color: #fff; }
.nav-menu a.active { color: #fff; font-weight: 600; }

/* 语言切换 */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-shrink: 0;
}
.lang-btn {
  padding: 4px 10px;
  font-size: 0.78rem;
  font-weight: 600;
  border-radius: 3px;
  border: 1px solid rgba(255,255,255,0.4);
  color: rgba(255,255,255,0.85);
  transition: all var(--transition);
  letter-spacing: 0.02em;
}
.lang-btn:hover { border-color: #fff; color: #fff; }
.lang-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* 汉堡菜单 */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  margin-left: auto;
}
.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: #fff;
  transition: all var(--transition);
  border-radius: 2px;
}
#navbar.scrolled .nav-toggle span { background: var(--text-main); }

/* ===== 页面 Hero 标题区（非首页） ===== */
.page-hero {
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%);
  padding: calc(var(--nav-height) + 50px) 0 60px;
  text-align: center;
  color: #fff;
  position: relative;
  overflow: hidden;
}
.page-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}
.page-hero h1 {
  font-size: 2.4rem;
  font-weight: 700;
  position: relative;
}
.page-hero .breadcrumb {
  margin-top: 12px;
  font-size: 0.88rem;
  opacity: 0.75;
  position: relative;
}
.page-hero .breadcrumb a { color: inherit; }
.page-hero .breadcrumb a:hover { opacity: 1; text-decoration: underline; }

/* ===== 首页 Banner ===== */
#banner {
  position: relative;
  height: 100vh;
  min-height: 600px;
  max-height: 850px;
  overflow: hidden;
  background: var(--bg-dark);
}
.banner-slides { position: relative; height: 100%; }
.banner-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 0.8s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}
.banner-slide.active { opacity: 1; }
.banner-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  filter: brightness(0.45);
  transition: transform 8s ease;
}
.banner-slide.active .banner-bg { transform: scale(1.05); }
.banner-content {
  position: relative;
  text-align: center;
  color: #fff;
  padding: 0 20px;
  max-width: 800px;
}
.banner-content h2 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1.2rem;
  text-shadow: 0 2px 20px rgba(0,0,0,0.4);
  animation: fadeUp 0.8s ease 0.3s both;
}
.banner-content p {
  font-size: clamp(1rem, 2vw, 1.25rem);
  opacity: 0.9;
  margin-bottom: 2.5rem;
  animation: fadeUp 0.8s ease 0.5s both;
}
.banner-btns {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeUp 0.8s ease 0.7s both;
}
.banner-dots {
  position: absolute;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 10;
}
.banner-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,0.4);
  cursor: pointer;
  transition: all var(--transition);
}
.banner-dot.active { background: var(--accent); width: 28px; border-radius: 5px; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== 核心业务 ===== */
#core-business { padding: 80px 0; }
.core-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  margin-top: 3rem;
}
.core-card {
  text-align: center;
  padding: 40px 30px;
  border-radius: var(--radius-lg);
  background: var(--bg-white);
  border: 1px solid var(--border);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.core-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--primary);
  transform: scaleX(0);
  transition: transform var(--transition);
}
.core-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}
.core-card:hover::before { transform: scaleX(1); }
.core-icon {
  width: 72px; height: 72px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 24px;
  font-size: 1.8rem;
  color: #fff;
  transition: transform var(--transition);
}
.core-card:hover .core-icon { transform: rotate(10deg) scale(1.1); }
.core-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 12px;
}
.core-card p { color: var(--text-gray); font-size: 0.93rem; line-height: 1.8; }

/* ===== 产品展示 ===== */
#home-products { background: var(--bg-light); }
.products-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 40px;
}
.product-card {
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: all var(--transition);
  cursor: pointer;
}
.product-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-light);
}
.product-card-img {
  width: 100%;
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, #e8f0fe 0%, #c5d8f7 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  overflow: hidden;
  position: relative;
}
.product-card-img img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform var(--transition);
}
.product-card:hover .product-card-img img { transform: scale(1.08); }
.product-card-body { padding: 18px; }
.product-card-body h4 {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--primary-dark);
  margin-bottom: 6px;
}
.product-card-body p {
  font-size: 0.83rem;
  color: var(--text-light);
  line-height: 1.6;
}
.product-tag {
  display: inline-block;
  padding: 2px 10px;
  background: rgba(10,61,122,0.08);
  color: var(--primary);
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-top: 8px;
}
.products-more { text-align: center; }

/* ===== 行业应用 ===== */
.industry-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 20px;
}
.industry-item {
  text-align: center;
  padding: 28px 16px;
  border-radius: var(--radius);
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  transition: all var(--transition);
  cursor: default;
}
.industry-item:hover {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.25);
  transform: translateY(-4px);
}
.industry-icon {
  font-size: 2.2rem;
  margin-bottom: 12px;
}
.industry-item p { font-size: 0.85rem; color: rgba(255,255,255,0.85); font-weight: 500; }

/* ===== 关于我们页面 ===== */
.about-intro {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: start;
  margin-bottom: 80px;
}
.about-intro-text h2 {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 1.5rem;
}
.about-intro-text p {
  color: var(--text-gray);
  margin-bottom: 1rem;
  line-height: 1.9;
}
.about-intro-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, var(--primary-dark), var(--primary));
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.5);
  font-size: 0.9rem;
}
.about-intro-img img { width: 100%; height: 100%; object-fit: cover; }

.scope-cards {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 1.5rem;
}
.scope-tag {
  padding: 8px 20px;
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: 30px;
  font-size: 0.88rem;
  color: var(--primary);
  font-weight: 600;
  transition: all var(--transition);
}
.scope-tag:hover { background: var(--primary); color: #fff; border-color: var(--primary); }

.mission-vision {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
  margin-top: 60px;
}
.mv-card {
  padding: 40px;
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
}
.mv-card.mission { background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%); color: #fff; }
.mv-card.vision { background: linear-gradient(135deg, var(--accent) 0%, var(--accent-light) 100%); color: #fff; }
.mv-card h3 { font-size: 1.3rem; font-weight: 700; margin-bottom: 1rem; opacity: 0.9; }
.mv-card p { font-size: 0.98rem; line-height: 1.9; opacity: 0.9; }
.mv-icon { font-size: 3rem; opacity: 0.2; position: absolute; right: 30px; bottom: 20px; }

/* 时间线 */
.timeline { position: relative; padding-left: 30px; margin-top: 3rem; }
.timeline::before {
  content: '';
  position: absolute;
  left: 10px; top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--primary), var(--border));
}
.timeline-item {
  position: relative;
  padding: 0 0 40px 30px;
}
.timeline-item::before {
  content: '';
  position: absolute;
  left: -4px; top: 6px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--primary);
  border: 3px solid var(--bg-white);
  box-shadow: 0 0 0 2px var(--primary);
}
.timeline-year {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 4px;
  letter-spacing: 0.05em;
}
.timeline-desc { color: var(--text-gray); font-size: 0.93rem; }

/* ===== 产品中心页面 ===== */
.products-page-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
  align-items: start;
}
.products-sidebar {
  background: var(--bg-light);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  position: sticky;
  top: calc(var(--nav-height) + 20px);
}
.sidebar-title {
  padding: 18px 20px;
  background: var(--primary);
  color: #fff;
  font-weight: 700;
  font-size: 0.95rem;
}
.sidebar-menu li {
  border-bottom: 1px solid var(--border);
}
.sidebar-menu li:last-child { border-bottom: none; }
.sidebar-menu a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 13px 20px;
  font-size: 0.9rem;
  color: var(--text-gray);
  transition: all var(--transition);
}
.sidebar-menu a:hover, .sidebar-menu a.active {
  background: rgba(10,61,122,0.06);
  color: var(--primary);
  padding-left: 26px;
}
.sidebar-menu a.active { font-weight: 600; }

.products-main-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.product-page-card {
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  overflow: hidden;
  transition: all var(--transition);
}
.product-page-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
.product-page-card-img {
  aspect-ratio: 16/10;
  background: linear-gradient(135deg, #e8f0fe, #c5d8f7);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.5rem;
  overflow: hidden;
}
.product-page-card-img img { width: 100%; height: 100%; object-fit: cover; }
.product-page-card-body { padding: 20px; }
.product-page-card-body h4 { font-size: 1rem; font-weight: 700; color: var(--primary-dark); margin-bottom: 8px; }
.product-page-card-body p { font-size: 0.85rem; color: var(--text-gray); line-height: 1.7; margin-bottom: 14px; }
.product-page-card-body .btn { font-size: 0.82rem; padding: 8px 18px; }

/* ===== 服务支持页面 ===== */
.service-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 30px;
  margin-bottom: 70px;
}
.service-card {
  display: flex;
  gap: 24px;
  padding: 36px;
  background: #fff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  transition: all var(--transition);
}
.service-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: var(--primary-light); }
.service-card-icon {
  width: 60px; height: 60px;
  flex-shrink: 0;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: #fff;
}
.service-card-text h3 { font-size: 1.1rem; font-weight: 700; color: var(--primary-dark); margin-bottom: 8px; }
.service-card-text p { font-size: 0.9rem; color: var(--text-gray); line-height: 1.8; }

.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}
.faq-q {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  cursor: pointer;
  font-weight: 600;
  color: var(--primary-dark);
  background: #fff;
  transition: background var(--transition);
  user-select: none;
}
.faq-q:hover { background: var(--bg-light); }
.faq-q::after {
  content: '+';
  font-size: 1.4rem;
  color: var(--primary);
  transition: transform var(--transition);
  flex-shrink: 0;
  margin-left: 16px;
}
.faq-item.open .faq-q::after { transform: rotate(45deg); }
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  background: var(--bg-light);
}
.faq-a-inner { padding: 0 24px 20px; color: var(--text-gray); font-size: 0.93rem; line-height: 1.8; }
.faq-item.open .faq-a { max-height: 200px; }

/* ===== 联系我们页面 ===== */
.contact-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
}
.contact-info-card {
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%);
  color: #fff;
  border-radius: var(--radius-lg);
  padding: 50px 40px;
}
.contact-info-card h2 { font-size: 1.6rem; font-weight: 700; margin-bottom: 32px; }
.contact-item {
  display: flex;
  gap: 16px;
  margin-bottom: 28px;
  align-items: flex-start;
}
.contact-item-icon {
  width: 44px; height: 44px;
  flex-shrink: 0;
  background: rgba(255,255,255,0.15);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}
.contact-item-body label {
  display: block;
  font-size: 0.78rem;
  opacity: 0.7;
  margin-bottom: 4px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.contact-item-body span, .contact-item-body a {
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
}
.contact-item-body a:hover { text-decoration: underline; }

.map-wrap {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  height: 100%;
  min-height: 400px;
  background: var(--bg-light);
}
.map-wrap iframe { width: 100%; height: 100%; border: none; min-height: 400px; }

/* ===== 页脚 ===== */
#footer {
  background: #0a1628;
  color: rgba(255,255,255,0.75);
  padding: 60px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 50px;
  padding-bottom: 50px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.footer-brand { }
.footer-logo-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}
.footer-logo-row img { height: 36px; }
.footer-company-name {
  font-size: 1rem;
  font-weight: 700;
  color: #fff;
  line-height: 1.3;
}
.footer-brand p { font-size: 0.85rem; line-height: 1.8; margin-bottom: 20px; }
.footer-contact-list { list-style: none; }
.footer-contact-list li {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 10px;
  font-size: 0.85rem;
}
.footer-contact-list li span:first-child { font-size: 1rem; opacity: 0.6; }

.footer-col h4 {
  color: #fff;
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 20px;
  position: relative;
  padding-bottom: 10px;
}
.footer-col h4::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0;
  width: 24px; height: 2px;
  background: var(--accent);
}
.footer-col ul li { margin-bottom: 10px; font-size: 0.85rem; }
.footer-col ul a { font-size: 0.85rem; transition: color var(--transition); }
.footer-col ul a:hover { color: #fff; }

.footer-bottom {
  padding: 20px 0;
  text-align: center;
  font-size: 0.8rem;
  opacity: 0.55;
}
.footer-bottom a { color: inherit; }
.footer-bottom a:hover { opacity: 1; }

/* ===== 统计数字区 ===== */
.stats-section {
  background: var(--primary);
  color: #fff;
  padding: 50px 0;
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  text-align: center;
}
.stat-item .stat-num {
  font-size: 2.5rem;
  font-weight: 800;
  color: #fff;
  display: block;
}
.stat-item .stat-unit { font-size: 1.2rem; font-weight: 700; }
.stat-item p { font-size: 0.88rem; opacity: 0.8; margin-top: 6px; }

/* ===== 通用工具 ===== */
.text-center { text-align: center; }
.mt-60 { margin-top: 60px; }
.hidden { display: none !important; }

/* ===== 回到顶部 ===== */
#back-top {
  position: fixed;
  right: 30px; bottom: 30px;
  width: 44px; height: 44px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-md);
  opacity: 0;
  pointer-events: none;
  transition: all var(--transition);
  z-index: 999;
  cursor: pointer;
  border: none;
}
#back-top.show { opacity: 1; pointer-events: auto; }
#back-top:hover { background: var(--accent); transform: translateY(-3px); }

/* ===== 动画 ===== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .products-grid { grid-template-columns: repeat(3, 1fr); }
  .industry-grid { grid-template-columns: repeat(3, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  :root { --nav-height: 60px; }
  .section-title { font-size: 1.6rem; }
  section { padding: 60px 0; }

  .nav-menu, .lang-switcher { display: none; }
  .nav-toggle { display: flex; }

  .nav-menu.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: var(--nav-height); left: 0; right: 0;
    background: var(--bg-white);
    box-shadow: var(--shadow-md);
    padding: 16px 0;
    gap: 0;
  }
  .nav-menu.open a {
    color: var(--text-main);
    line-height: 1;
    padding: 14px 24px;
  }
  .nav-menu.open a::after { display: none; }
  .nav-menu.open + .lang-switcher {
    display: flex;
    position: fixed;
    top: calc(var(--nav-height) + 10px);
    right: 16px;
  }

  .core-grid { grid-template-columns: 1fr; }
  .products-grid { grid-template-columns: repeat(2, 1fr); }
  .industry-grid { grid-template-columns: repeat(2, 1fr); }
  .about-intro { grid-template-columns: 1fr; }
  .mission-vision { grid-template-columns: 1fr; }
  .products-page-layout { grid-template-columns: 1fr; }
  .products-sidebar { position: static; }
  .products-main-grid { grid-template-columns: repeat(2, 1fr); }
  .service-grid { grid-template-columns: 1fr; }
  .contact-layout { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; }
  #back-top { right: 16px; bottom: 16px; }
}

@media (max-width: 480px) {
  .products-grid { grid-template-columns: 1fr; }
  .industry-grid { grid-template-columns: repeat(2, 1fr); }
  .products-main-grid { grid-template-columns: 1fr; }
  .banner-btns { flex-direction: column; align-items: center; }
}