/* ============================
   低空经济大模型平台 - 主样式 v2
   纯黑白灰主题 + 企业级视频背景
   ============================ */

:root {
  --bg-primary: #000000;
  --bg-secondary: #0a0a0a;
  --bg-card: #111111;
  --bg-card-hover: #1a1a1a;
  --text-primary: #ffffff;
  --text-secondary: #e8e8e8;
  --text-muted: #aaaaaa;
  --text-dim: #777777;
  --accent: #ffffff;
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(255, 255, 255, 0.25);
  --glow: rgba(255, 255, 255, 0.1);
  --shadow-card: 0 4px 30px rgba(0, 0, 0, 0.5);
  --font-cn: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-en: 'Inter', 'Montserrat', sans-serif;
  --section-padding: 120px 0;
  --container-width: 1200px;
  --nav-height: 72px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-cn);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  position: relative;
}

/* 全局背景线条图 - 底层固定 */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('../images/bg-lines.png') no-repeat center center;
  background-size: cover;
  filter: brightness(0.35) blur(1px);
  z-index: -1;
}

/* 所有区块背景透明 */
section,
.features-section,
.stats,
.data-section,
.architecture,
.partners {
  background: transparent !important;
}

/* Hero和沙盘保持深色背景遮罩 */
.hero-overlay {
  background: rgba(0,0,0,0.4);
}

.sandbox-map {
  background: rgba(6,6,8,0.85);
}

/* 半透明卡片 */
.cap-card,
.chart-card,
.arch-node {
  background: rgba(17, 17, 17, 0.75);
  backdrop-filter: blur(10px);
}

/* Footer半透明 */
.footer {
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(10px);
}

/* 导航栏半透明 */
.navbar.scrolled {
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(20px);
}

a { color: inherit; text-decoration: none; transition: color var(--transition-fast); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

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

/* --- SVG图标通用样式 --- */
.icon {
  width: 24px;
  height: 24px;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  fill: none;
  flex-shrink: 0;
}

.icon-sm { width: 18px; height: 18px; }
.icon-lg { width: 32px; height: 32px; }
.icon-xl { width: 40px; height: 40px; }

/* --- Section标题 --- */
.section-header { text-align: center; margin-bottom: 72px; }

.section-label {
  display: inline-block;
  font-family: var(--font-en);
  font-size: 11px;
  letter-spacing: 5px;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 20px;
}

.section-title {
  font-size: 44px;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: 2px;
}

.section-subtitle {
  font-size: 16px;
  color: var(--text-muted);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.8;
}

/* ============================
   1. 导航栏
   ============================ */
.navbar {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 48px;
  z-index: 1000;
  transition: background var(--transition-normal), backdrop-filter var(--transition-normal);
}

.navbar.scrolled {
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-bottom: 1px solid var(--border-subtle);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 1px;
}

.nav-logo .icon { width: 28px; height: 28px; color: #fff; }

.nav-menu {
  display: flex;
  align-items: center;
  gap: 36px;
}

.nav-menu a {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
  position: relative;
  padding: 4px 0;
  letter-spacing: 0.5px;
  transition: color var(--transition-fast);
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 0;
  width: 0; height: 1px;
  background: #fff;
  transition: width var(--transition-normal);
}

.nav-menu a:hover { color: #fff; }
.nav-menu a:hover::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 16px; }

.btn-outline {
  padding: 9px 22px;
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 6px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  background: transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.btn-outline:hover { border-color: #fff; color: #fff; }

.btn-primary {
  padding: 9px 22px;
  border: none;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 600;
  color: #000;
  background: #fff;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.btn-primary:hover { background: #e0e0e0; box-shadow: 0 0 20px rgba(255,255,255,0.15); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: #fff;
  transition: all var(--transition-normal);
}

/* ============================
   2. Hero首屏 - 视频背景
   ============================ */
.hero {
  position: relative;
  height: 100vh;
  min-height: 700px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero-video-wrap {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: 0;
}

.hero-video-wrap video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(30%) brightness(0.7) contrast(1.05);
  transition: opacity 0.1s linear;
}

.hero-overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background:
    radial-gradient(ellipse at 50% 50%, transparent 0%, rgba(0,0,0,0.35) 70%),
    linear-gradient(180deg, rgba(0,0,0,0.1) 0%, transparent 20%, transparent 70%, rgba(0,0,0,0.5) 100%);
  z-index: 1;
  transition: opacity 0.1s linear;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 0 24px;
  transition: opacity 0.1s linear;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 20px;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 100px;
  font-size: 12px;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 36px;
  background: rgba(255,255,255,0.04);
  backdrop-filter: blur(12px);
  letter-spacing: 1px;
}

.hero-badge-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: #fff;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.3; transform: scale(0.8); }
}

.hero-title {
  font-size: 68px;
  font-weight: 900;
  line-height: 1.1;
  margin-bottom: 28px;
  letter-spacing: 6px;
}

.hero-subtitle {
  font-size: 18px;
  color: var(--text-muted);
  margin-bottom: 52px;
  letter-spacing: 10px;
  font-weight: 300;
}

.hero-tags {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 0;
}

.hero-tag {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 8px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  background: rgba(255,255,255,0.03);
  backdrop-filter: blur(8px);
  transition: all var(--transition-normal);
}

.hero-tag:hover {
  border-color: rgba(255,255,255,0.4);
  background: rgba(255,255,255,0.08);
  transform: translateY(-2px);
}

.hero-tag .icon { width: 16px; height: 16px; opacity: 0.7; }

.hero-scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-dim);
  font-family: var(--font-en);
  font-size: 10px;
  letter-spacing: 3px;
  animation: scrollBounce 2.5s infinite;
}

.hero-scroll-line {
  width: 1px; height: 40px;
  background: linear-gradient(to bottom, rgba(255,255,255,0.5), transparent);
}

@keyframes scrollBounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(10px); }
}

/* 功能卡片 */
.cap-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  padding-bottom: var(--section-padding);
}

.cap-card {
  position: relative;
  display: block;
  padding: 44px 36px;
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  background: var(--bg-card);
  transition: all var(--transition-normal);
  overflow: hidden;
  text-decoration: none;
  color: inherit;
}

.cap-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.cap-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-6px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.4);
  background: var(--bg-card-hover);
}

.cap-card:hover::before { opacity: 1; }

.cap-icon {
  width: 52px; height: 52px;
  border-radius: 12px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 28px;
  transition: all var(--transition-normal);
}

.cap-icon .icon { width: 24px; height: 24px; color: var(--text-secondary); }

.cap-card:hover .cap-icon {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.2);
}

.cap-number {
  font-family: var(--font-en);
  font-size: 11px;
  color: var(--text-dim);
  letter-spacing: 3px;
  margin-bottom: 14px;
}

.cap-title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.cap-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.8;
}

.cap-arrow {
  position: absolute;
  bottom: 36px; right: 36px;
  width: 32px; height: 32px;
  border: 1px solid var(--border-subtle);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-dim);
  transition: all var(--transition-normal);
}

.cap-arrow .icon { width: 14px; height: 14px; }

.cap-card:hover .cap-arrow {
  border-color: rgba(255,255,255,0.4);
  color: #fff;
  transform: translateX(4px);
}

/* ============================
   3.5 平台功能区（沙盘+卡片）
   ============================ */
.features-section {
  padding: var(--section-padding) 0;
  padding-bottom: 0;
  background: var(--bg-primary);
}

.sandbox-map {
  position: relative;
  width: 100%;
  height: 520px;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  background: #060608;
  overflow: hidden;
  margin-bottom: 72px;
}

/* 预览图层 */
.sandbox-preview {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  filter: grayscale(80%) brightness(0.4) blur(1px);
  opacity: 0;
  transition: opacity 0.5s ease;
  z-index: 1;
  pointer-events: none;
}

.sandbox-preview.active { opacity: 1; }
.sandbox-preview.fade-out { opacity: 0; }

/* 网格 */
.sandbox-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.025) 1px, transparent 1px);
  background-size: 48px 48px;
  z-index: 2;
}

/* 航线SVG */
.sandbox-routes {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 3;
}

.route-line {
  stroke-dashoffset: 0;
}
.route-1 { animation: routeFlow 25s linear infinite; }
.route-2 { animation: routeFlow 30s linear infinite reverse; }
.route-3 { animation: routeFlow 22s linear infinite; }
.route-4 { animation: routeFlow 35s linear infinite reverse; }

@keyframes routeFlow {
  0% { stroke-dashoffset: 0; }
  100% { stroke-dashoffset: -200; }
}

/* 飞行器动画 */
.drone-anim {
  position: absolute;
  z-index: 5;
  opacity: 0.7;
  filter: drop-shadow(0 0 6px rgba(255,255,255,0.5));
}

.drone-anim-1 {
  animation: droneFly1 18s linear infinite;
}
.drone-anim-2 {
  animation: droneFly2 22s linear infinite;
  animation-delay: -6s;
}
.drone-anim-3 {
  animation: droneFly3 20s linear infinite;
  animation-delay: -10s;
}

@keyframes droneFly1 {
  0%   { left: 6%;  top: 80%; }
  20%  { left: 22%; top: 42%; }
  40%  { left: 42%; top: 38%; }
  60%  { left: 65%; top: 25%; }
  80%  { left: 85%; top: 30%; }
  100% { left: 6%;  top: 80%; }
}

@keyframes droneFly2 {
  0%   { left: 5%;  top: 15%; }
  20%  { left: 25%; top: 50%; }
  40%  { left: 48%; top: 55%; }
  60%  { left: 70%; top: 65%; }
  80%  { left: 90%; top: 45%; }
  100% { left: 5%;  top: 15%; }
}

@keyframes droneFly3 {
  0%   { left: 8%;  top: 50%; }
  25%  { left: 30%; top: 20%; }
  50%  { left: 55%; top: 50%; }
  75%  { left: 78%; top: 55%; }
  100% { left: 8%;  top: 50%; }
}

/* ============================
   功能节点（航线站点）
   ============================ */
.sandbox-node {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: inherit;
  z-index: 10;
  cursor: pointer;
}

.sandbox-node:hover { transform: scale(1.08); }

/* 脉冲环 */
.node-ring {
  position: absolute;
  width: 56px; height: 56px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,0.15);
  top: -4px;
  animation: ringPulse 3s ease-in-out infinite;
  opacity: 0;
}

.sandbox-node:hover .node-ring {
  border-color: rgba(255,255,255,0.4);
}

@keyframes ringPulse {
  0%, 100% { transform: scale(1); opacity: 0; }
  50% { transform: scale(1.6); opacity: 0.6; }
}

/* 中心点 */
.node-dot {
  position: absolute;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: rgba(255,255,255,0.5);
  top: 22px;
  box-shadow: 0 0 8px rgba(255,255,255,0.4);
  transition: all 0.3s ease;
}

.sandbox-node:hover .node-dot {
  background: #fff;
  box-shadow: 0 0 16px rgba(255,255,255,0.8);
  transform: scale(1.5);
}

/* 图标盒 */
.node-icon-box {
  width: 48px; height: 48px;
  border-radius: 12px;
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.85);
  transition: all 0.35s ease;
  backdrop-filter: blur(8px);
  /* 淡入动画 */
  opacity: 0;
  transform: translateY(10px) scale(0.9);
  animation: nodeFadeIn 0.6s ease forwards;
}

.node-1 .node-icon-box { animation-delay: 0.1s; }
.node-2 .node-icon-box { animation-delay: 0.2s; }
.node-3 .node-icon-box { animation-delay: 0.3s; }
.node-4 .node-icon-box { animation-delay: 0.4s; }
.node-5 .node-icon-box { animation-delay: 0.5s; }
.node-6 .node-icon-box { animation-delay: 0.6s; }

@keyframes nodeFadeIn {
  to { opacity: 1; transform: translateY(0) scale(1); }
}

.sandbox-node:hover .node-icon-box {
  background: rgba(255,255,255,0.15);
  border-color: rgba(255,255,255,0.4);
  box-shadow: 0 0 24px rgba(255,255,255,0.15);
  color: #fff;
}

/* 标签 */
.node-label {
  font-size: 11px;
  font-weight: 600;
  color: rgba(255,255,255,0.45);
  white-space: nowrap;
  letter-spacing: 0.5px;
  transition: color 0.3s ease;
  opacity: 0;
  animation: nodeFadeIn 0.6s ease forwards;
  animation-delay: 0.3s;
}

.node-1 .node-label { animation-delay: 0.4s; }
.node-2 .node-label { animation-delay: 0.5s; }
.node-3 .node-label { animation-delay: 0.6s; }
.node-4 .node-label { animation-delay: 0.7s; }
.node-5 .node-label { animation-delay: 0.8s; }
.node-6 .node-label { animation-delay: 0.9s; }

.sandbox-node:hover .node-label { color: rgba(255,255,255,0.9); }

/* 节点位置（均匀分布） */
.node-1 { left: 8%;  top: 18%; }
.node-2 { left: 75%; top: 15%; }
.node-3 { left: 42%; top: 10%; }
.node-4 { left: 12%; top: 62%; }
.node-5 { left: 72%; top: 62%; }
.node-6 { left: 85%; top: 40%; }

/* 地图标注 */
.map-label {
  position: absolute;
  font-size: 10px;
  font-weight: 600;
  color: rgba(255,255,255,0.15);
  letter-spacing: 4px;
  text-transform: uppercase;
  z-index: 3;
  pointer-events: none;
}

.label-city    { left: 20%; top: 48%; }
.label-sea     { right: 10%; top: 52%; }
.label-airport { left: 22%; bottom: 12%; }

/* 响应式 */
@media (max-width: 1200px) {
  .cap-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .sandbox-map { height: 380px; }
  .node-icon-box { width: 40px; height: 40px; }
  .node-icon-box svg { width: 18px; height: 18px; }
  .node-label { font-size: 9px; }
  .cap-grid { grid-template-columns: 1fr; }
}

/* ============================
   4. 视频场景区
   ============================ */
.scenes {
  padding: var(--section-padding);
  background: var(--bg-secondary);
  position: relative;
}

.scenes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.scene-card {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
  transition: all var(--transition-normal);
  cursor: pointer;
  aspect-ratio: 16 / 9;
}

.scene-card:hover {
  border-color: var(--border-hover);
  box-shadow: 0 12px 48px rgba(0,0,0,0.6);
  transform: translateY(-4px);
}

.scene-media {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
}

.scene-media video,
.scene-media img {
  width: 100%; height: 100%;
  object-fit: cover;
  filter: grayscale(80%) brightness(0.5);
  transition: all var(--transition-slow);
}

.scene-card:hover .scene-media video,
.scene-card:hover .scene-media img {
  filter: grayscale(40%) brightness(0.6);
  transform: scale(1.05);
}

.scene-placeholder {
  width: 100%; height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.scene-placeholder-bg {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  opacity: 0.4;
}

.scene-overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: linear-gradient(180deg, transparent 30%, rgba(0,0,0,0.85) 100%);
  z-index: 1;
}

.scene-content {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  padding: 36px;
  z-index: 2;
}

.scene-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 14px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 4px;
  font-family: var(--font-en);
  font-size: 10px;
  color: var(--text-muted);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 14px;
  backdrop-filter: blur(8px);
}

.scene-title {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.scene-desc {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.7;
}

.scene-play {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  z-index: 3;
  width: 72px; height: 72px;
  border-radius: 50%;
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: all var(--transition-normal);
  backdrop-filter: blur(12px);
}

.scene-play .icon { width: 28px; height: 28px; color: #fff; margin-left: 3px; }

.scene-card:hover .scene-play {
  opacity: 1;
  background: rgba(255,255,255,0.25);
}

/* ============================
   5. 数据展示区
   ============================ */
.stats {
  padding: 100px 0;
  background: var(--bg-primary);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  position: relative;
}

.stats-video-bg {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: 0;
  overflow: hidden;
}

.stats-video-bg video {
  width: 100%; height: 100%;
  object-fit: cover;
  filter: grayscale(100%) brightness(0.15);
  opacity: 0.5;
}

.stats-overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.7);
  z-index: 1;
}

.stats .container { position: relative; z-index: 2; }

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  text-align: center;
}

.stat-item { padding: 24px; }

.stat-number {
  font-family: var(--font-en);
  font-size: 56px;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
  margin-bottom: 12px;
}

.stat-suffix {
  font-size: 24px;
  font-weight: 400;
  color: var(--text-dim);
}

.stat-label {
  font-size: 13px;
  color: var(--text-muted);
  letter-spacing: 2px;
}

/* ============================
   5. 平台数据可视化区
   ============================ */
.data-section {
  padding: var(--section-padding);
  background: var(--bg-secondary);
}

/* 大数字行 */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
  margin-bottom: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--border-subtle);
}

.stat-number {
  font-family: var(--font-en);
  font-size: 52px;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
  margin-bottom: 10px;
}

.stat-suffix {
  font-size: 22px;
  font-weight: 400;
  color: var(--text-dim);
}

.stat-label {
  font-size: 13px;
  color: var(--text-muted);
  letter-spacing: 1px;
}

/* 图表行 */
.charts-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.chart-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  padding: 24px;
  transition: all var(--transition-normal);
}

.chart-card:hover {
  border-color: var(--border-hover);
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.chart-card-title {
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
  margin-bottom: 8px;
}

/* 数据摘要 */
.chart-summary {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 16px;
}

.chart-big-num {
  font-family: var(--font-en);
  font-size: 28px;
  font-weight: 800;
  color: var(--text-primary);
}

.chart-change {
  font-size: 12px;
  font-weight: 600;
  font-family: var(--font-en);
}

.chart-change.up {
  color: #4ade80;
}

.chart-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 8px;
}

.chart-labels span {
  font-size: 10px;
  color: var(--text-dim);
}

/* 柱状图 */
.bar-chart {
  display: flex;
  align-items: flex-end;
  gap: 4px;
  height: 70px;
}

.bar-col {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.bar {
  width: 100%;
  height: var(--h);
  background: rgba(255,255,255,0.12);
  border-radius: 3px 3px 0 0;
  transition: all 0.4s ease;
  position: relative;
}

.bar.active {
  background: rgba(255,255,255,0.45);
}

.bar-val {
  position: absolute;
  top: -18px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 9px;
  font-family: var(--font-en);
  color: var(--text-dim);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.bar-col:hover .bar-val {
  opacity: 1;
}

.bar-col:hover .bar {
  background: rgba(255,255,255,0.3);
}

.bar-col:hover .bar.active {
  background: rgba(255,255,255,0.6);
}

/* 折线图 */
.line-chart {
  height: 70px;
}

.line-chart svg {
  width: 100%;
  height: 100%;
}

.line-chart .line {
  stroke-dasharray: 400;
  stroke-dashoffset: 400;
  animation: drawLine 2s ease forwards;
}

@keyframes drawLine {
  to { stroke-dashoffset: 0; }
}

.chart-data-points {
  display: flex;
  justify-content: space-between;
  margin-top: 4px;
}

.chart-data-points span {
  font-size: 10px;
  font-family: var(--font-en);
  color: var(--text-dim);
}

/* 环形图 */
.ring-chart-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 90px;
}

.ring-chart {
  position: relative;
  width: 80px;
  height: 80px;
}

.ring-chart svg {
  width: 100%;
  height: 100%;
}

/* 环形图详情 */
.ring-details {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 12px;
}

.ring-detail-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--text-muted);
}

.ring-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.ring-detail-val {
  margin-left: auto;
  font-family: var(--font-en);
  font-weight: 600;
  color: var(--text-secondary);
}

/* 响应式 */
@media (max-width: 1200px) {
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .charts-row { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .stats-row { grid-template-columns: 1fr 1fr; gap: 32px; }
  .stat-number { font-size: 38px; }
}

/* ============================
   6. 技术架构区
   ============================ */
.architecture {
  padding: var(--section-padding);
  background: var(--bg-secondary);
  position: relative;
}

.arch-flow {
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 0;
}

.arch-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 36px 28px;
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  background: var(--bg-card);
  min-width: 180px;
  text-align: center;
  transition: all var(--transition-normal);
  position: relative;
}

.arch-node:hover {
  border-color: var(--border-hover);
  transform: translateY(-6px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.3);
  background: var(--bg-card-hover);
}

.arch-icon {
  width: 52px; height: 52px;
  border-radius: 50%;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-normal);
}

.arch-icon .icon { width: 24px; height: 24px; color: var(--text-secondary); }

.arch-node:hover .arch-icon {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.25);
}

.arch-label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
}

.arch-desc {
  font-size: 12px;
  color: var(--text-dim);
}

.arch-arrow {
  display: flex;
  align-items: center;
  padding: 0 8px;
  color: var(--text-dim);
}

.arch-arrow .icon { width: 20px; height: 20px; }

/* ============================
   7. 合作伙伴区
   ============================ */
.partners {
  padding: 80px 0;
  background: var(--bg-primary);
  overflow: hidden;
}

.partners-track {
  display: flex;
  gap: 56px;
  animation: scrollLeft 35s linear infinite;
}

.partner-logo {
  flex-shrink: 0;
  height: 36px;
  padding: 0 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0.25;
  transition: opacity var(--transition-normal);
  font-size: 15px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 3px;
  white-space: nowrap;
  text-transform: uppercase;
}

.partner-logo:hover { opacity: 0.6; }

@keyframes scrollLeft {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

/* Hero CTA按钮 */
.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-top: 48px;
}

.btn-hero-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 36px;
  background: #fff;
  color: #000;
  font-size: 15px;
  font-weight: 600;
  border-radius: 8px;
  transition: all var(--transition-normal);
}

.btn-hero-primary:hover {
  background: #e0e0e0;
  box-shadow: 0 0 30px rgba(255,255,255,0.15);
  transform: translateY(-2px);
}

.btn-hero-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 36px;
  border: 1px solid rgba(255,255,255,0.3);
  color: var(--text-secondary);
  font-size: 15px;
  font-weight: 500;
  border-radius: 8px;
  transition: all var(--transition-normal);
}

.btn-hero-outline:hover {
  border-color: #fff;
  color: #fff;
  transform: translateY(-2px);
}

/* ============================
   9. Footer
   ============================ */
.footer {
  padding: 80px 0 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 60px;
}

.footer-brand { max-width: 320px; }

.footer-brand-name {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.footer-brand-name .icon { width: 22px; height: 22px; }

.footer-brand-desc {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 28px;
}

.footer-social { display: flex; gap: 12px; }

.footer-social a {
  width: 36px; height: 36px;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-dim);
  transition: all var(--transition-fast);
}

.footer-social a .icon { width: 16px; height: 16px; }

.footer-social a:hover {
  border-color: rgba(255,255,255,0.3);
  color: #fff;
}

.footer-col-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 22px;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.footer-links { display: flex; flex-direction: column; gap: 14px; }

.footer-links a {
  font-size: 13px;
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

.footer-links a:hover { color: #fff; }

.footer-bottom {
  padding: 24px 0;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-dim);
}

.footer-bottom a { color: var(--text-dim); }
.footer-bottom a:hover { color: #fff; }

/* ============================
   滚动动画
   ============================ */
.fade-up {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.9s cubic-bezier(0.4, 0, 0.2, 1), transform 0.9s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.fade-up-delay-1 { transition-delay: 0.08s; }
.fade-up-delay-2 { transition-delay: 0.16s; }
.fade-up-delay-3 { transition-delay: 0.24s; }
.fade-up-delay-4 { transition-delay: 0.32s; }
.fade-up-delay-5 { transition-delay: 0.40s; }
.fade-up-delay-6 { transition-delay: 0.48s; }

/* ============================
   响应式
   ============================ */

/* 平板 */
@media (max-width: 1200px) {
  .cap-grid { grid-template-columns: repeat(2, 1fr); }
  .charts-row { grid-template-columns: 1fr; }
}

@media (max-width: 992px) {
  .nav-menu { display: none; }
  .nav-toggle { display: flex; }
  .hero-title { font-size: 44px; letter-spacing: 2px; }
  .hero-subtitle { font-size: 14px; letter-spacing: 4px; }
  .section-title { font-size: 32px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .arch-flow { flex-wrap: wrap; justify-content: center; gap: 16px; }
  .arch-arrow { display: none; }
  .hero-cta { flex-direction: column; gap: 12px; }
  .sandbox-map { height: 380px; }
  .stats-row { grid-template-columns: repeat(2, 1fr); gap: 24px; }
}

/* 手机 */
@media (max-width: 768px) {
  :root {
    --section-padding: 64px 0;
    --nav-height: 56px;
  }

  /* 导航 */
  .navbar { padding: 0 16px; }
  .nav-logo span { font-size: 14px; }
  .nav-actions .btn-outline { display: none; }

  /* Hero */
  .hero { min-height: 100vh; min-height: 100svh; }
  .hero-video-wrap video {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }
  .hero-title { font-size: 32px; letter-spacing: 1px; }
  .hero-subtitle { font-size: 13px; letter-spacing: 2px; }
  .hero-tags { gap: 8px; }
  .hero-tag { font-size: 11px; padding: 8px 12px; gap: 6px; }
  .hero-tag .icon { width: 14px; height: 14px; }
  .hero-badge { font-size: 11px; padding: 6px 14px; }
  .hero-cta { margin-top: 32px; }
  .btn-hero-primary, .btn-hero-outline {
    width: 100%;
    justify-content: center;
    padding: 14px 24px;
    font-size: 14px;
  }

  /* 区块标题 */
  .section-header { margin-bottom: 40px; }
  .section-title { font-size: 26px; }
  .section-subtitle { font-size: 13px; }

  /* 沙盘 */
  .sandbox-map { height: 300px; margin-bottom: 48px; }
  .sandbox-node { transform: scale(0.85); }
  .node-icon-box { width: 40px; height: 40px; }
  .node-icon-box svg { width: 18px; height: 18px; }
  .node-label { font-size: 9px; }
  .map-label { font-size: 8px; letter-spacing: 2px; }

  /* 功能卡片 */
  .cap-grid { grid-template-columns: 1fr; gap: 16px; }
  .cap-card { padding: 28px 24px; }
  .cap-title { font-size: 17px; }
  .cap-desc { font-size: 13px; }
  .cap-arrow { display: none; }

  /* 大数字 */
  .stats-row {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 36px;
    padding-bottom: 36px;
  }
  .stat-number { font-size: 36px; }
  .stat-suffix { font-size: 18px; }
  .stat-label { font-size: 11px; }

  /* 图表卡片 */
  .charts-row { grid-template-columns: 1fr; gap: 16px; }
  .chart-card { padding: 20px; }
  .chart-big-num { font-size: 24px; }
  .bar-chart { height: 60px; }

  /* 技术架构 */
  .arch-flow { gap: 12px; }
  .arch-node { min-width: 140px; padding: 24px 16px; }
  .arch-label { font-size: 13px; }
  .arch-desc { font-size: 11px; }

  /* 合作伙伴 */
  .partners { padding: 48px 0; }
  .partners-track { gap: 32px; }
  .partner-logo { font-size: 13px; padding: 0 20px; }

  /* Footer */
  .footer { padding: 48px 0 0; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-brand { max-width: 100%; }
  .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
}

/* 小手机 */
@media (max-width: 480px) {
  .hero-title { font-size: 26px; }
  .hero-subtitle { font-size: 12px; letter-spacing: 1px; }
  .hero-tags { flex-direction: column; align-items: stretch; }
  .hero-tag { justify-content: center; }
  .section-title { font-size: 22px; }
  .stats-row { grid-template-columns: 1fr 1fr; gap: 16px; }
  .stat-number { font-size: 30px; }
  .sandbox-map { height: 260px; }
  .sandbox-node { transform: scale(0.75); }
}

/* 移动端背景图适配 */
@media (max-width: 768px) {
  body::before {
    background-size: cover;
    background-position: center;
  }

  /* 确保视频在移动端可显示 */
  .hero-video-wrap {
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
  }

  .hero-video-wrap video {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }

  /* 移动端视频降级为图片 */
  .hero-video-wrap::after {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: linear-gradient(135deg, #0a0a0a 0%, #1a1a2e 50%, #0a0a0a 100%);
    z-index: -1;
  }
}

/* 移动端菜单 */
.nav-menu.active {
  display: flex;
  flex-direction: column;
  position: fixed;
  top: var(--nav-height);
  left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.97);
  backdrop-filter: blur(24px);
  padding: 32px 24px;
  gap: 20px;
  z-index: 999;
  overflow-y: auto;
}

.nav-menu.active a {
  font-size: 16px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border-subtle);
}

/* 汉堡菜单动画 */
.nav-toggle span {
  transition: all 0.3s ease;
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* 视频弹窗 */
.video-modal {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.96);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
}
.video-modal.active { opacity: 1; visibility: visible; }

.video-modal-content {
  width: 80%;
  max-width: 960px;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: 12px;
  overflow: hidden;
  position: relative;
  border: 1px solid rgba(255,255,255,0.1);
}

.video-modal-close {
  position: absolute;
  top: -48px; right: 0;
  width: 36px; height: 36px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,0.2);
  background: transparent;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}
.video-modal-close:hover { border-color: #fff; }