/* ============================================================
   VNEX.cn — 主样式表
   Clean Tech 基底 + Cyberpunk 霓虹点缀
   全屏滚动 · 玻璃态卡片 · 渐变光晕
   ============================================================ */

/* ---- 1. CSS 自定义属性 ---- */
:root {
  /* 背景体系 — 夜空蓝渐变 */
  --bg-deep: #0d1128;
  --bg: rgba(17, 23, 56, 0.93);
  --bg-alt: rgba(22, 29, 70, 0.93);
  --bg-card: rgba(22, 30, 65, 0.65);
  --bg-card-solid: rgba(26, 34, 82, 0.95);
  --bg-glass: rgba(17, 23, 56, 0.55);

  /* 主色 — 紫霓虹 */
  --primary: #7c6ff0;
  --primary-dark: #5a4dd6;
  --primary-light: #a99efc;
  --primary-glow: rgba(124, 111, 240, 0.35);
  --primary-glow-weak: rgba(124, 111, 240, 0.15);

  /* 强调色 — 青霓虹 */
  --accent: #00ddd4;
  --accent-glow: rgba(0, 221, 212, 0.3);
  --accent-glow-weak: rgba(0, 221, 212, 0.12);

  /* 文字层级 */
  --text: #d8dae5;
  --text-secondary: #a0a3b8;
  --text-muted: #636780;
  --text-dim: #4a4d63;

  /* 边框 */
  --border: rgba(255, 255, 255, 0.08);
  --border-light: rgba(255, 255, 255, 0.12);
  --border-glow: rgba(124, 111, 240, 0.25);

  /* 玻璃态 */
  --glass-bg: rgba(22, 30, 65, 0.55);
  --glass-border: rgba(255, 255, 255, 0.09);
  --glass-blur: 18px;

  /* 圆角 */
  --radius: 16px;
  --radius-sm: 10px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-full: 999px;

  /* 间距 */
  --gap-xs: 8px;
  --gap-sm: 16px;
  --gap-md: 24px;
  --gap-lg: 40px;
  --gap-xl: 64px;

  /* 过渡 */
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

  /* 字体 */
  --font-heading: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --font-body: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;

  /* 容器宽度 */
  --max-width: 1200px;
}

/* ---- 2. 基础与排版 ---- */
html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: var(--bg-deep);
}

body {
  font-family: var(--font-body);
  line-height: 1.7;
  color: var(--text);
  background: transparent;
  overflow-x: hidden;
}

/* 网格纹理 — 覆盖在所有内容之上 */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 9998;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(124, 111, 240, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(124, 111, 240, 0.06) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: linear-gradient(180deg,
    transparent 0%,
    rgba(0,0,0,0.4) 20%,
    rgba(0,0,0,0.8) 50%,
    rgba(0,0,0,1) 100%);
  -webkit-mask-image: linear-gradient(180deg,
    transparent 0%,
    rgba(0,0,0,0.4) 20%,
    rgba(0,0,0,0.8) 50%,
    rgba(0,0,0,1) 100%);
}


h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.3;
  color: #e4e4f0;
}

a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition);
}

img { max-width: 100%; display: block; }

/* ---- 3. 滚动条 ---- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb {
  background: rgba(124, 111, 240, 0.3);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover { background: rgba(124, 111, 240, 0.5); }

/* ---- 4. 导航栏 — 玻璃态 + 霓虹底边 ---- */
#site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  transition: all var(--transition);
}

#site-nav::after {
  content: '';
  position: absolute;
  bottom: 0; left: 24px; right: 24px;
  height: 1px;
  background: linear-gradient(90deg,
    transparent 0%,
    rgba(124, 111, 240, 0.3) 20%,
    rgba(0, 221, 212, 0.3) 80%,
    transparent 100%);
  opacity: 0;
  transition: opacity var(--transition);
}

#site-nav.scrolled { background: var(--glass-bg); backdrop-filter: blur(var(--glass-blur)); }
#site-nav.scrolled::after { opacity: 1; }

.nav-inner {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.15rem;
  font-weight: 700;
  color: #e4e4f0;
  letter-spacing: 0.5px;
}

.logo-dot {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  font-size: 0.65rem;
  font-weight: 800;
  color: #e4e4f0;
  letter-spacing: 0;
  box-shadow: 0 0 16px var(--primary-glow);
}

/* 导航链接 */
.nav-links {
  display: flex;
  list-style: none;
  gap: 4px;
  margin: 0; padding: 0;
}

.nav-links a {
  display: block;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  color: var(--text-secondary);
  font-weight: 500;
  position: relative;
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: #e4e4f0;
  background: rgba(124, 111, 240, 0.1);
}

.nav-links a.active {
  box-shadow: 0 0 12px var(--primary-glow-weak);
}

/* 汉堡菜单 */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all var(--transition);
}

.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---- 5. 全屏滚动吸附（仅首页） ---- */
.home {
  scroll-snap-type: y proximity;
  scroll-behavior: smooth;
}

.home > section {
  scroll-snap-align: start;
}

/* ---- 6. Hero Banner — 全屏第一屏 ---- */
#banner {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: linear-gradient(170deg, rgba(13,17,40,0.95) 0%, rgba(17,23,56,0.93) 40%, rgba(26,34,80,0.93) 100%);
}

#banner .bg {
  position: absolute;
  inset: 0;
  background: url('/bannermax.jpg') center/cover no-repeat;
  opacity: 0.08;
}

#banner .overlay {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 50% 40%, rgba(13,17,40,0.45) 0%, rgba(13,17,40,0.65) 60%, var(--bg-deep) 100%);
}

#banner #particles-canvas {
  position: absolute;
  inset: 0;
  z-index: 1;
}

#banner .content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 800px;
  padding: 0 24px;
}

#banner .pre-title {
  display: inline-block;
  padding: 6px 18px;
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  color: #e4e4f0;
  letter-spacing: 2px;
  margin-bottom: 28px;
  background: rgba(124, 111, 240, 0.12);
}

#banner h1 {
  font-size: 3rem;
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 16px;
  color: #e4e4f0;
}

#banner .sub-title {
  font-size: 1.15rem;
  color: var(--text);
  margin-bottom: 12px;
  letter-spacing: 6px;
  font-weight: 300;
}

#banner .tagline {
  font-size: 0.9rem;
  color: var(--text-secondary);
  letter-spacing: 3px;
  margin-bottom: 40px;
}

#banner .typing-text {
  color: var(--accent);
  animation: blink 1.2s infinite;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.2; }
}

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

/* 滚动提示 */
#banner .scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  color: var(--text-dim);
  letter-spacing: 2px;
  z-index: 2;
  animation: float 2s ease-in-out infinite;
}

#banner .scroll-hint span {
  width: 1px; height: 20px;
  background: linear-gradient(180deg, transparent, var(--primary));
  border-radius: 1px;
}

@keyframes float {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ---- 7. 数据亮点 — 全屏第二屏 ---- */
#stats {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(180deg, rgba(22,29,70,0.93) 0%, var(--bg) 100%);
  position: relative;
}

#stats::before {
  content: '';
  position: absolute;
  top: 0; left: 50%;
  transform: translateX(-50%);
  width: 1px; height: 60px;
  background: linear-gradient(180deg, var(--primary-glow) 0%, transparent 100%);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  max-width: 900px;
  width: 100%;
  padding: 0 24px;
}

.stat-item {
  text-align: center;
  padding: 48px 24px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.stat-item::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, var(--primary-glow-weak) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition);
}

.stat-item:hover {
  border-color: var(--border-glow);
  transform: translateY(-4px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4), 0 0 20px var(--primary-glow-weak);
}

.stat-item:hover::before { opacity: 1; }

.stat-number {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1;
  margin-bottom: 8px;
  color: var(--primary-light);
}

.stat-label {
  font-size: 0.9rem;
  color: var(--text-muted);
  letter-spacing: 1px;
}

/* ---- 8. 通用区块组件 ---- */
.section {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 80px 24px;
}

.section:nth-child(odd) { background: var(--bg); }
.section:nth-child(even) { background: var(--bg-alt); }

.section-inner {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-label {
  display: inline-block;
  font-size: 0.75rem;
  letter-spacing: 3px;
  color: var(--primary-light);
  text-transform: uppercase;
  margin-bottom: 12px;
  position: relative;
  padding-left: 28px;
}

.section-label::before {
  content: '';
  position: absolute;
  left: 0; top: 50%;
  transform: translateY(-50%);
  width: 18px; height: 1px;
  background: var(--primary-glow);
}

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: #e4e4f0;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 48px;
}

/* ---- 9. 业务范围卡片 ---- */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.service-card {
  display: block;
  padding: 36px 28px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.service-card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius);
  border: 1px solid transparent;
  transition: all var(--transition);
}

.service-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-glow);
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.5), 0 0 24px var(--primary-glow-weak);
  background: var(--bg-card-solid);
}

.service-card:hover::after {
  border-color: var(--primary);
  mask: linear-gradient(135deg, transparent 20%, rgba(124,111,240,0.5) 50%, transparent 80%);
  -webkit-mask: linear-gradient(135deg, transparent 20%, rgba(124,111,240,0.5) 50%, transparent 80%);
}

.service-icon {
  font-size: 2.5rem;
  margin-bottom: 20px;
  line-height: 1;
}

.service-card h3 {
  font-size: 1.2rem;
  margin-bottom: 10px;
  color: #e4e4f0;
}

.service-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ---- 10. 运营网站卡片（浏览器视窗） ---- */
.websites-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 28px;
}

.browser-card {
  display: block;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}

.browser-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-glow);
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.5), 0 0 24px var(--accent-glow-weak);
}

.browser-bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 14px 18px;
  background: rgba(0, 0, 0, 0.25);
  border-bottom: 1px solid var(--border);
}

.browser-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  animation: dot-breathe 1.8s ease-in-out infinite;
}

.browser-dot.red    { background: #ff5f57; }
.browser-dot.yellow { background: #febc2e; }
.browser-dot.green  { background: #28c840; }

@keyframes dot-breathe {
  0%, 100% { opacity: 0.7; transform: scale(0.96); }
  50%      { opacity: 1;   transform: scale(1.03); }
}

.browser-card:hover .browser-dot {
  animation-duration: 0.9s;
}

.browser-url {
  margin-left: 12px;
  padding: 4px 12px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 4px;
  font-size: 0.72rem;
  color: var(--text-muted);
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.browser-body {
  padding: 32px 24px;
  text-align: center;
}

.web-icon {
  width: 56px; height: 56px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  font-weight: 700;
  color: #e4e4f0;
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
}

.browser-body h3 {
  font-size: 1.1rem;
  margin-bottom: 6px;
  color: #e4e4f0;
}

.browser-body .url-text {
  font-size: 0.78rem;
  color: var(--accent);
  margin-bottom: 12px;
  display: block;
}

.browser-body p {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

/* ---- 11. 物流代理卡片 ---- */
.logistics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.logistics-card {
  display: block;
  padding: 40px 28px;
  text-align: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.logistics-card:hover {
  transform: translateY(-6px);
  border-color: var(--accent-glow);
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.5), 0 0 24px var(--accent-glow-weak);
  background: var(--bg-card-solid);
}

.logistics-icon {
  width: 64px; height: 64px;
  margin: 0 auto 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  color: #e4e4f0;
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
}

.logistics-card h3 {
  font-size: 1.15rem;
  margin-bottom: 10px;
  color: #e4e4f0;
}

.logistics-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

/* ---- 12. CTA 行动号召 — 全屏 ---- */
#cta {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0 24px;
  background: linear-gradient(180deg,
    var(--bg-alt) 0%,
    rgba(30,40,84,0.93) 40%,
    var(--bg) 100%);
  position: relative;
  overflow: hidden;
}

#cta::before {
  content: '';
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 600px; height: 600px;
  background: radial-gradient(circle, var(--primary-glow-weak) 0%, transparent 70%);
  pointer-events: none;
}

.cta-title {
  position: relative;
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: #e4e4f0;
}

.cta-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 480px;
  line-height: 1.7;
}

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

/* ---- 13. 按钮组件 ---- */
.btn-primary,
.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
}

.btn-primary {
  position: relative;
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-light);
}

.btn-primary::after {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(124, 111, 240, 0.35);
  animation: pulse-ring 2.5s ease-out infinite;
  pointer-events: none;
}

@keyframes pulse-ring {
  0%   { transform: scale(0.95); opacity: 0.6; }
  100% { transform: scale(1.18); opacity: 0; }
}

.btn-primary:hover {
  border-color: var(--primary);
  color: #fff;
  background: rgba(124, 111, 240, 0.08);
  transform: translateY(-2px);
  box-shadow: 0 0 16px var(--primary-glow-weak);
}

.btn-primary:hover::after {
  animation: none;
  opacity: 0;
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-light);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: #fff;
  background: rgba(124, 111, 240, 0.08);
  transform: translateY(-2px);
  box-shadow: 0 0 16px var(--primary-glow-weak);
}

/* ---- 14. 页脚 ---- */
#footer {
  background: linear-gradient(180deg, var(--bg) 0%, rgba(13,17,40,0.96) 100%);
  padding: 80px 24px 0;
  position: relative;
}

#footer::before {
  content: '';
  position: absolute;
  top: 0; left: 24px; right: 24px;
  height: 1px;
  background: linear-gradient(90deg,
    transparent 0%,
    rgba(124, 111, 240, 0.2) 30%,
    rgba(0, 221, 212, 0.2) 70%,
    transparent 100%);
}

.footer-upper {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-inner { padding: 0; }

.footer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 0.85fr;
  gap: 48px;
  margin-bottom: 36px;
}

.footer-brand .brand-logo {
  margin-bottom: 16px;
}

.footer-brand .brand-logo .logo-text {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px; height: 44px;
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  font-size: 0.7rem;
  font-weight: 800;
  color: #e4e4f0;
}

.footer-brand h4 {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.footer-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  max-width: 280px;
  line-height: 1.7;
}

.footer-heading {
  font-size: 0.82rem;
  letter-spacing: 2px;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
  display: inline-block;
}

.footer-qr-list {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.qr-item {
  text-align: center;
}

.qr-img {
  width: 100px; height: 100px;
  border-radius: var(--radius-sm);
  background: #fff;
  padding: 6px;
  margin-bottom: 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}

.qr-label {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.footer-contact .contact-item {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.footer-contact .contact-item a {
  color: var(--text-secondary);
  transition: color var(--transition);
}

.footer-contact .contact-item a:hover { color: var(--primary-light); }

.contact-icon {
  width: 18px; height: 18px;
  display: inline-block;
  opacity: 1;
  filter: brightness(1.3);
}

.tel-icon::before   { content: '📞'; font-size: 16px; }
.email-icon::before { content: '✉️'; font-size: 16px; }
.addr-icon::before  { content: '📍'; font-size: 16px; }

.footer-icon-list {
  display: flex;
  gap: 12px;
  margin-top: 16px;
}

.footer-icon-link img {
  width: 24px; height: 24px;
  opacity: 0.85;
  filter: brightness(0) invert(1);
  transition: opacity var(--transition), transform var(--transition), filter var(--transition);
}

.footer-icon-link:hover img {
  opacity: 1;
  filter: brightness(0) invert(1) drop-shadow(0 0 6px rgba(124,111,240,0.4));
  transform: scale(1.15);
}

.footer-bottom {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 24px;
  padding: 20px 24px;
  border-top: 1px solid var(--border);
  font-size: 0.78rem;
  color: var(--text-dim);
}

/* ---- 15. 悬浮操作 ---- */
.floating-actions {
  position: fixed;
  bottom: 32px;
  right: 32px;
  z-index: 900;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.floating-actions .back-to-top {
  width: 44px; height: 44px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition);
  font-size: 1.1rem;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
}

.floating-actions .back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.floating-actions .back-to-top:hover {
  border-color: var(--primary);
  color: #fff;
  box-shadow: 0 0 16px var(--primary-glow-weak);
}

/* ---- 16. 动画工具类 ---- */
.fade-in-section {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-in-section.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---- 17. 桌面大屏 (≥1400px) ---- */
@media (min-width: 1400px) {
  #banner h1 { font-size: 3.5rem; }
}

/* ---- 18. 平板 (≤1024px) ---- */
@media (max-width: 1024px) {
  .home { scroll-snap-type: none; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 20px; }
  .stat-item { padding: 36px 20px; }
  .stat-number { font-size: 2.4rem; }

  .section { min-height: auto; padding: 80px 24px; }
  #stats { min-height: auto; padding: 80px 24px; }
  #banner { min-height: auto; padding: 120px 24px 80px; }

  .section-title { font-size: 2rem; }
  #banner h1 { font-size: 2.2rem; }
  .cta-title { font-size: 2rem; }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 36px;
  }
}

/* ---- 19. 手机 (≤640px) ---- */
@media (max-width: 640px) {
  #site-nav { padding: 0 16px; height: 56px; }

  .nav-links {
    position: fixed;
    top: 56px; left: 0; right: 0;
    flex-direction: column;
    background: rgba(17, 23, 56, 0.95);
    backdrop-filter: blur(20px);
    padding: 12px;
    border-bottom: 1px solid var(--border);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-links a { padding: 12px 16px; border-radius: var(--radius-sm); }

  .nav-toggle { display: flex; }

  .stats-grid { grid-template-columns: 1fr 1fr; gap: 12px; }
  .stat-item { padding: 28px 12px; }
  .stat-number { font-size: 2rem; }

  .services-grid,
  .websites-grid,
  .logistics-grid { grid-template-columns: 1fr; }

  #banner h1 { font-size: 1.8rem; }
  .section-title { font-size: 1.7rem; }
  .cta-title { font-size: 1.7rem; }

  .banner-btns { flex-direction: column; align-items: center; }
  .cta-btns { flex-direction: column; align-items: center; }

  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-brand .footer-desc { max-width: 100%; }

  .floating-actions { bottom: 20px; right: 20px; }

  .section { padding: 60px 20px; }
  #banner { padding: 100px 20px 60px; }
  #stats { padding: 60px 20px; }
  #cta { padding: 60px 20px; }
}