/* ===== 基础变量（拓竹风格升级：层次灰 + 深色锚点 + 绿） ===== */
:root {
  --bg: #f3f5f8;           /* 主背景：柔和冷灰，替代刺眼纯白 */
  --bg-soft: #e8ecf1;      /* 次级灰：更深一档，拉开层次 */
  --bg-card: #ffffff;       /* 卡片白：在灰底上浮起 */
  --bg-dark: #0d1410;       /* 深色锚点：深绿黑 */
  --bg-dark-soft: #131c16;  /* 深色二级 */
  --ink: #1a1e25;           /* 主文字 */
  --ink-soft: #5a6270;      /* 次文字 */
  --ink-mute: #99a1ab;      /* 弱文字 */
  --ink-dark: #e8ede8;      /* 深色背景上的主文字 */
  --ink-dark-soft: rgba(255,255,255,0.68); /* 深色背景上的次文字 */
  --ink-dark-mute: rgba(255,255,255,0.42); /* 深色背景上的弱文字 */
  --line: #dde2e8;          /* 浅色分割线 */
  --line-dark: rgba(255,255,255,0.10); /* 深色分割线 */
  --primary: #00b14f;        /* 拓竹绿 */
  --primary-d: #008c3e;      /* 深绿 hover */
  --primary-2: #2dd06b;      /* 亮绿 */
  --primary-soft: #e8f7ee;   /* 极浅绿底 */
  --radius: 18px;
  --radius-sm: 12px;
  --shadow: 0 20px 56px -24px rgba(15, 23, 32, 0.18);
  --shadow-sm: 0 8px 24px -16px rgba(15, 23, 32, 0.20);
  --shadow-card: 0 2px 8px -2px rgba(15, 23, 32, 0.06), 0 8px 24px -12px rgba(15, 23, 32, 0.08);
  --container: 1160px;
  --maxw: 1160px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

a { color: inherit; text-decoration: none; }

h1, h2, h3 { line-height: 1.2; font-weight: 800; letter-spacing: -0.02em; }

.eyebrow {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--primary-d);
  margin-bottom: 16px;
  padding: 5px 14px;
  background: var(--primary-soft);
  border-radius: 999px;
}

.accent { color: var(--primary); }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 28px;
  border-radius: 12px;
  font-weight: 700;
  font-size: 15px;
  cursor: pointer;
  border: 1.5px solid transparent;
  transition: transform .15s ease, box-shadow .2s ease, background .2s ease, border-color .2s ease;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-d) 100%);
  color: #fff;
  box-shadow: 0 14px 30px -14px rgba(0,177,79,.55);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 18px 36px -14px rgba(0,177,79,.65); }
.btn-ghost { border-color: var(--line); color: var(--ink); background: var(--bg-card); }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary-d); background: var(--primary-soft); }

/* ===== 导航 ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(243,245,248,.82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s, box-shadow .25s, background .25s;
}
.nav.scrolled { border-color: var(--line); box-shadow: 0 8px 28px -22px rgba(0,0,0,.12); background: rgba(243,245,248,.94); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 70px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); }
.brand-mark { color: var(--primary); }
.brand-text {
  font-family: "Inter", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: 0.02em;
  white-space: nowrap;
}
.brand-text strong { color: var(--primary); font-weight: 800; }
.nav-links { display: flex; gap: 30px; }
.nav-links a { font-size: 15px; font-weight: 600; color: var(--ink-soft); transition: color .2s; }
.nav-links a:hover { color: var(--primary-d); }
.nav-cta { padding: 9px 20px; font-size: 14px; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 6px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--ink); border-radius: 2px; transition: .25s; }

/* ===== Hero ===== */
.hero { position: relative; overflow: hidden; padding: 96px 0 104px; background: linear-gradient(180deg, #f7f9fb 0%, #eef1f5 100%); color: var(--ink); }
.hero-bg { position: absolute; inset: 0; z-index: 0; }
.grid-overlay {
  position: absolute; inset: 0;
  background-image: linear-gradient(rgba(20,24,29,.045) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(20,24,29,.045) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(ellipse 82% 72% at 60% 35%, #000 35%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 82% 72% at 60% 35%, #000 35%, transparent 100%);
}
.glow { position: absolute; border-radius: 50%; filter: blur(100px); }
.glow-1 { width: 460px; height: 460px; background: rgba(0,177,79,.16); top: -140px; right: -60px; }
.glow-2 { width: 380px; height: 380px; background: rgba(0,177,79,.12); bottom: -150px; left: -100px; }

/* 首屏书法 Logo 水印（浅底上用淡灰，若隐若现） */
.hero-logo-watermark {
  position: absolute;
  left: -1%;
  top: -6%;
  height: 56vh;
  max-height: 460px;
  width: auto;
  object-fit: contain;
  opacity: .10;
  pointer-events: none;
  z-index: 0;
  filter: grayscale(100%);
}

.hero-inner { position: relative; z-index: 1; display: flex; justify-content: center; text-align: center; }
.hero-copy { max-width: 780px; margin: 0 auto; }
.hero-actions, .hero-stats { justify-content: center; }
.hero .eyebrow { color: var(--primary-d); }
.hero h1 { font-size: clamp(36px, 5.2vw, 60px); margin-bottom: 24px; letter-spacing: -0.03em; line-height: 1.15; }
.hero .lead { color: var(--ink-soft); font-size: 18px; max-width: 560px; margin: 0 auto 36px; line-height: 1.8; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.hero .btn-ghost { border-color: var(--line); color: var(--ink); }
.hero .btn-ghost:hover { border-color: var(--primary); color: var(--primary-d); }
.hero-stats { list-style: none; display: flex; gap: 16px; margin-top: 52px; flex-wrap: wrap; justify-content: center; }
.hero-stats li { display: flex; flex-direction: column; align-items: center; }
.hero-stats strong {
  font-size: 14px; font-weight: 700; color: var(--primary-d);
  padding: 8px 18px; border-radius: 999px;
  background: var(--primary-soft); border: 1px solid rgba(0,177,79,.18);
  letter-spacing: 0.01em;
}
.hero-stats span { font-size: 13px; color: var(--ink-mute); }

/* 首屏为纯文字页，双螺杆动画已移除 */
.pellet.p4 { animation-delay: 2.2s; }
@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

/* ===== 通用 Section ===== */
.section { padding: 96px 0; background: var(--bg); }
.section-alt { background: var(--bg-soft); }
.section-dark {
  background: var(--bg-dark);
  color: var(--ink-dark);
}
.section-dark .section-head h2 { color: var(--ink-dark); }
.section-dark .section-head p { color: var(--ink-dark-soft); }
.section-dark .eyebrow {
  color: var(--primary-2);
  background: rgba(0,177,79,.12);
}
.section-head { max-width: 740px; margin: 0 auto 56px; text-align: center; }
.section-head h2 { font-size: clamp(28px, 4vw, 42px); margin-bottom: 18px; letter-spacing: -0.025em; }
.section-head p { color: var(--ink-soft); font-size: 17px; line-height: 1.75; max-width: 640px; margin: 0 auto; }

/* ===== 关于卡片 ===== */
.about-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 34px 30px;
  box-shadow: var(--shadow-card);
  transition: transform .2s, box-shadow .2s, border-color .2s;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  opacity: 0; transition: opacity .2s;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: rgba(0,177,79,.3); }
.card:hover::before { opacity: 1; }
.card-icon { font-size: 32px; margin-bottom: 18px; }
.card h3 { font-size: 20px; margin-bottom: 12px; }
.card p { color: var(--ink-soft); font-size: 15px; line-height: 1.7; }

/* ===== 流程 ===== */
.flow { list-style: none; display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; counter-reset: step; }
.flow li {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 40px 28px;
  position: relative;
  box-shadow: var(--shadow-card);
  transition: transform .2s, box-shadow .2s, border-color .2s;
}
.flow li:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: rgba(0,177,79,.3); }
.flow-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 52px; height: 52px; border-radius: 14px;
  background: var(--primary-soft); color: var(--primary-d);
  font-weight: 800; margin-bottom: 20px; font-size: 20px;
}
.section-dark .flow-num {
  background: rgba(0,177,79,.15); color: var(--primary-2);
}
.section-dark .flow h3 { color: var(--ink); }
.section-dark .flow p { color: var(--ink-soft); }
.flow h3 { font-size: 22px; margin-bottom: 12px; }
.flow p { color: var(--ink-soft); font-size: 16px; line-height: 1.75; }

/* ===== 设备 ===== */
.product {
  display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center;
  background: var(--bg-card); border: 1px solid var(--line);
  border-radius: 24px; padding: 44px;
  box-shadow: var(--shadow);
}
.product-visual {
  position: relative; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, #f0f4f8 0%, #e8ecf1 100%); border-radius: 16px; padding: 0; border: 1px solid var(--line);
  overflow: hidden; min-height: 420px; height: 420px;
}
.product-visual svg { width: 100%; max-width: 300px; }
.product-3d-iframe {
  position: absolute; inset: 0;
  display: block; width: 100%; height: 100%;
  border: none; border-radius: 16px; background: transparent;
}
.iframe-fallback {
  position: absolute; left: 50%; bottom: 18px; transform: translateX(-50%);
  font-size: 12px; color: var(--ink-soft); background: rgba(255,255,255,.9);
  padding: 6px 14px; border-radius: 999px; border: 1px solid var(--line);
  backdrop-filter: blur(4px); z-index: 5; opacity: 1; pointer-events: auto;
  transition: opacity .3s; box-shadow: 0 2px 8px rgba(0,0,0,.05);
}
.product-visual:hover .iframe-fallback { opacity: 1; }
.spec-badge {
  position: absolute; top: 16px; left: 16px;
  background: linear-gradient(135deg, var(--primary), var(--primary-d)); color: #fff; font-weight: 800;
  padding: 6px 14px; border-radius: 999px; font-size: 14px;
  box-shadow: 0 4px 14px -4px rgba(0,177,79,.5);
}
.product-info { display: flex; flex-direction: column; justify-content: space-between; gap: 28px; }
.spec-list { list-style: none; }
.spec-list li {
  display: flex; justify-content: space-between; gap: 16px;
  padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 15px;
}
.spec-list li:last-child { border-bottom: 0; padding-bottom: 0; }
.spec-list li:first-child { padding-top: 0; }
.spec-list span { color: var(--ink-soft); }
.spec-list strong { text-align: right; }
.btn-buy {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  width: 100%; padding: 16px 28px; border-radius: 14px;
  background: linear-gradient(135deg, #ff6a00 0%, #e85a00 100%); color: #fff;
  font-size: 16px; font-weight: 700; text-decoration: none;
  box-shadow: 0 14px 32px -12px rgba(255,106,0,.45);
  transition: transform .15s ease, box-shadow .2s ease, background .2s ease;
}
.btn-buy:hover { transform: translateY(-2px); box-shadow: 0 18px 36px -12px rgba(255,106,0,.55); filter: brightness(1.05); }
.btn-buy:active { transform: translateY(0); }
.btn-buy svg { width: 20px; height: 20px; flex: none; }

/* ===== 优势 ===== */
.adv-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.adv {
  background: var(--bg-card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 30px 28px;
  box-shadow: var(--shadow-card);
  transition: transform .2s, border-color .2s, box-shadow .2s;
  position: relative;
  overflow: hidden;
}
.adv::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  opacity: 0; transition: opacity .2s;
}
.adv:hover { transform: translateY(-4px); border-color: rgba(0,177,79,.3); box-shadow: var(--shadow); }
.adv:hover::before { opacity: 1; }
.adv h3 { font-size: 19px; margin-bottom: 10px; color: var(--ink); }
.adv p { color: var(--ink-soft); font-size: 15px; line-height: 1.7; }
/* 深色背景上的优势卡片 */
.section-dark .adv {
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--line-dark);
  backdrop-filter: blur(4px);
}
.section-dark .adv:hover { background: rgba(255,255,255,0.08); border-color: rgba(0,177,79,.4); }
.section-dark .adv h3 { color: var(--ink-dark); }
.section-dark .adv p { color: var(--ink-dark-soft); }

/* ===== 应用 ===== */
.app-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.app {
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px 26px; background: var(--bg-card); transition: transform .2s, box-shadow .2s, border-color .2s;
}
.app:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: rgba(0,177,79,.4); }
.app-tag {
  display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: .08em;
  color: var(--primary-d); background: var(--primary-soft);
  padding: 5px 12px; border-radius: 999px; margin-bottom: 14px;
}
.app h3 { font-size: 19px; margin-bottom: 8px; }
.app p { color: var(--ink-soft); font-size: 15px; }

/* ===== 材料 ===== */
.mat-row { display: flex; flex-wrap: wrap; gap: 14px; justify-content: center; max-width: 820px; margin: 0 auto; }
.chip {
  border: 1px solid var(--line); color: var(--ink-soft); background: var(--bg-card);
  padding: 11px 22px; border-radius: 999px; font-size: 15px; font-weight: 600;
  box-shadow: 0 2px 6px -2px rgba(15,23,32,.06);
  transition: background .2s, color .2s, border-color .2s, transform .15s, box-shadow .2s;
}
.chip:hover { background: linear-gradient(135deg, var(--primary), var(--primary-d)); color: #fff; border-color: var(--primary); transform: translateY(-2px); box-shadow: 0 8px 20px -6px rgba(0,177,79,.4); }

/* ===== 联系 ===== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: start; }
.contact-copy h2 { font-size: clamp(28px, 4vw, 40px); margin-bottom: 16px; }
.contact-copy p { color: var(--ink-soft); margin-bottom: 28px; line-height: 1.75; }
.contact-list { list-style: none; }
.contact-list li { display: flex; gap: 14px; padding: 14px 0; border-bottom: 1px solid var(--line); align-items: center; }
.contact-list li:last-child { border-bottom: 0; }
.contact-list span { width: 64px; color: var(--ink-soft); font-size: 14px; flex-shrink: 0; }
.contact-list strong { font-size: 15px; }
.contact-form {
  background: var(--bg-card); border: 1px solid var(--line);
  border-radius: 22px; padding: 30px;
  box-shadow: var(--shadow-card);
}
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 7px; }
.field input, .field textarea {
  width: 100%; padding: 12px 14px; border: 1.5px solid var(--line);
  border-radius: 12px; font: inherit; background: var(--bg); resize: vertical;
  transition: border-color .2s, background .2s;
}
.field input:focus, .field textarea:focus { outline: none; border-color: var(--primary); background: var(--bg-card); }
.contact-form .btn { width: 100%; }
.form-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.form-actions .btn { width: auto; flex: 1 1 160px; }
.form-note { margin-top: 14px; color: var(--primary-d); font-weight: 600; font-size: 14px; }
.survey-thumb { position: relative; display: block; background: var(--bg-card); border: 1px solid var(--line); border-radius: 18px; overflow: hidden; cursor: pointer; transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease; text-decoration: none; box-shadow: var(--shadow-card); }
.survey-thumb:hover { transform: translateY(-3px); box-shadow: 0 16px 36px rgba(20,24,29,.14); border-color: rgba(0,177,79,.5); }
.survey-thumb-svg { display: block; width: 100%; height: auto; }
.survey-thumb-overlay { position: absolute; inset: 0; display: flex; align-items: flex-end; justify-content: center; padding-bottom: 20px; background: linear-gradient(to bottom, rgba(20,24,29,0) 55%, rgba(20,24,29,.45) 100%); opacity: 0; transition: opacity .25s ease; }
.survey-thumb:hover .survey-thumb-overlay { opacity: 1; }
.survey-thumb-cta { background: var(--primary); color: #fff; font-weight: 700; font-size: 15px; padding: 9px 20px; border-radius: 999px; box-shadow: 0 8px 20px rgba(0,177,79,.35); }

/* ===== Logo ===== */
.contact-alt { margin-top: 18px; font-size: 14px; color: var(--ink-soft); }
.contact-alt a { color: var(--primary-d); font-weight: 600; }

/* ===== 视频展示：拓竹风科技 Hero ===== */
.video-hero {
  position: relative;
  display: flex; align-items: center; justify-content: center;
  min-height: 92vh;
  padding: 120px 24px 100px;
  text-align: center;
  color: #fff;
  overflow: hidden;
  background: #07080a;
}
/* 海报图背景层（手机兜底：视频未加载时也能看到画面） */
.video-hero-poster {
  position: absolute; inset: 0; z-index: 0;
  pointer-events: none;
  background: url('../video/poster.jpg') center/cover no-repeat #07080a;
  filter: brightness(0.55) contrast(1.1) saturate(0.8);
  transition: opacity .8s ease;
}
/* 视频播放失败兜底：海报层更亮 */
.video-hero-bg-video.fallback ~ .video-hero-poster,
.video-hero-poster.fallback {
  filter: brightness(0.65) contrast(1.05) saturate(0.85);
}
/* 静音自动播放的背景视频（原生 video，全浏览器兼容） */
.video-hero-bg-video {
  position: absolute; inset: 0; z-index: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  opacity: 0;
  filter: brightness(0.78) contrast(1.05) saturate(0.9);
  pointer-events: none;
  transition: opacity .8s ease;
}
.video-hero-bg-video.playing { opacity: .55; }
/* 视频播放失败兜底：隐藏视频层 */
.video-hero-bg-video.fallback { opacity: 0; }

.video-hero-bg {
  position: absolute; inset: 0; z-index: 1;
  pointer-events: none;
  background:
    radial-gradient(circle at 50% 0%, rgba(0,177,79,.10), transparent 55%),
    radial-gradient(circle at 80% 80%, rgba(0,140,62,.08), transparent 45%),
    linear-gradient(180deg, rgba(7,8,10,.65) 0%, rgba(7,8,10,.75) 50%, rgba(7,8,10,.82) 100%);
}
.video-hero-grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
  background-size: 70px 70px;
  transform: perspective(600px) rotateX(60deg) translateY(-60px) scale(2.2);
  transform-origin: top center;
  opacity: .35;
  animation: gridMove 24s linear infinite;
  mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 0%, rgba(0,0,0,0) 85%);
  -webkit-mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 0%, rgba(0,0,0,0) 85%);
}
@keyframes gridMove {
  0% { transform: perspective(600px) rotateX(60deg) translateY(0) scale(2.2); }
  100% { transform: perspective(600px) rotateX(60deg) translateY(70px) scale(2.2); }
}
.video-hero-glow {
  position: absolute; border-radius: 50%; filter: blur(110px); pointer-events: none;
}
.video-hero-glow-1 { width: 520px; height: 520px; background: rgba(0,177,79,.18); top: -160px; left: 10%; animation: glowPulse 8s ease-in-out infinite; }
.video-hero-glow-2 { width: 380px; height: 380px; background: rgba(0,140,62,.14); bottom: -80px; right: 12%; animation: glowPulse 10s ease-in-out infinite 1.5s; }
.video-hero-glow-3 { width: 260px; height: 260px; background: rgba(45,208,107,.12); top: 40%; right: 25%; animation: glowPulse 7s ease-in-out infinite 2.5s; }
@keyframes glowPulse {
  0%, 100% { opacity: .55; transform: scale(1); }
  50% { opacity: .85; transform: scale(1.12); }
}
.video-hero-noise {
  position: absolute; inset: 0; opacity: .04; pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
.video-hero-inner {
  position: relative; z-index: 2;
  max-width: 860px; margin: 0 auto;
}
.video-hero-eyebrow {
  display: inline-block;
  font-size: 13px; font-weight: 700; letter-spacing: 0.18em; text-transform: uppercase;
  color: rgba(45,208,107,.85);
  margin-bottom: 22px;
  background: rgba(0,177,79,.12);
  padding: 7px 16px; border-radius: 999px;
  border: 1px solid rgba(0,177,79,.25);
  backdrop-filter: blur(4px);
}
.video-hero-title {
  font-size: clamp(34px, 5.5vw, 64px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 26px;
  text-shadow: 0 4px 30px rgba(0,0,0,.35);
}
.video-hero-lead {
  font-size: clamp(16px, 2vw, 20px);
  color: rgba(255,255,255,.72);
  max-width: 680px;
  margin: 0 auto 42px;
  line-height: 1.75;
}
.video-hero-actions {
  display: inline-flex; align-items: center; justify-content: center; gap: 18px;
  flex-wrap: wrap;
}
.video-hero-btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 15px 30px; border-radius: 12px; font-size: 16px; font-weight: 700;
  cursor: pointer; transition: transform .15s ease, box-shadow .2s ease, background .2s ease;
  border: 1.5px solid transparent;
  text-decoration: none;
}
.video-hero-btn-primary {
  background: #fff; color: #07080a;
  box-shadow: 0 14px 34px -12px rgba(255,255,255,.25);
}
.video-hero-btn-primary:hover { transform: translateY(-2px); background: #eafff2; box-shadow: 0 18px 40px -12px rgba(255,255,255,.35); }
.video-hero-btn-ghost {
  background: rgba(255,255,255,.08); color: #fff; border-color: rgba(255,255,255,.22);
  backdrop-filter: blur(6px);
}
.video-hero-btn-ghost:hover { background: rgba(255,255,255,.15); border-color: rgba(255,255,255,.35); transform: translateY(-2px); }
.video-hero-play-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 26px; height: 26px; border-radius: 50%; background: rgba(0,177,79,.15);
}
.video-hero-btn-primary .video-hero-play-icon { color: #00b14f; }
.video-hero-btn-ghost svg { stroke: currentColor; }

/* ===== 视频 Modal ===== */
.video-modal { position: fixed; inset: 0; z-index: 100; display: none; flex-direction: column; align-items: center; justify-content: center; padding: 24px; overflow: hidden; }
.video-modal.is-open { display: flex; }
.video-modal-backdrop { position: absolute; inset: 0; background: rgba(0,0,0,.86); backdrop-filter: blur(8px); cursor: pointer; }
.video-modal-content {
  position: relative; z-index: 1;
  width: 100%; max-width: 980px; aspect-ratio: 16 / 9;
  background: #000; border-radius: 16px; overflow: hidden;
  box-shadow: 0 40px 90px -30px rgba(0,0,0,.55);
  animation: modalIn .35s ease;
  pointer-events: auto;
}
@keyframes modalIn {
  from { opacity: 0; transform: translateY(18px) scale(.98); }
  to { opacity: 1; transform: none; }
}
.video-modal-close {
  position: absolute; top: -48px; right: 0; z-index: 10;
  width: 38px; height: 38px; border-radius: 50%;
  background: rgba(255,255,255,.12); color: #fff; border: 1px solid rgba(255,255,255,.25);
  font-size: 26px; line-height: 1; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background .2s, transform .2s;
  pointer-events: auto;
}
.video-modal-close:hover { background: rgba(255,255,255,.22); transform: rotate(90deg); }
.video-modal-frame { position: absolute; inset: 0; pointer-events: auto; }
.video-modal-frame iframe { width: 100%; height: 100%; border: 0; pointer-events: auto; }
/* iframe 加载失败时的兜底链接（视频下方，不遮挡画面） */
.video-modal-fallback {
  display: none; align-items: center; justify-content: center;
  margin-top: 16px; padding: 10px 20px; border-radius: 10px;
  background: rgba(255,255,255,.08); color: rgba(255,255,255,.7);
  font-size: 13px; font-weight: 600; text-decoration: none;
  transition: background .2s, color .2s;
  max-width: 980px; width: 100%;
}
.video-modal-fallback:hover { background: rgba(255,255,255,.15); color: #fff; }
.video-modal-fallback.is-visible { display: flex; }

/* ===== 页脚 ===== */
.footer { background: var(--bg-dark); color: var(--ink-dark); padding: 48px 0; border-top: 1px solid var(--line-dark); }
.footer-inner { display: flex; flex-direction: column; align-items: center; gap: 12px; text-align: center; }
.footer .brand { color: var(--ink-dark); }
.footer-tag { color: var(--ink-dark); font-size: 16px; font-weight: 700; }
.copyright { color: var(--ink-dark-mute); font-size: 13px; }

/* ===== 3D 模型展示（多角度静态图，100% 可靠无需 WebGL） ===== */
.model-viewer-block { margin-top: 56px; }
.model-viewer-head { text-align: center; max-width: 720px; margin: 0 auto 26px; }
.model-viewer-head h3 { font-size: clamp(22px, 3vw, 30px); margin-bottom: 8px; }
.model-viewer-head p { color: var(--ink-soft); font-size: 15px; }

.model-gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  width: 100%;
}
.model-shot{
  position: relative;
  display: block;
  background: linear-gradient(135deg, #f0f4f8, #e8ecf1);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 4 / 3;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
  box-shadow: var(--shadow-sm);
  text-decoration: none;
}
.model-shot:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 28px rgba(0, 30, 15, 0.12);
  border-color: var(--primary);
}
.model-shot img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  background: var(--bg-card);
}
.model-shot-label {
  position: absolute;
  left: 12px; bottom: 12px;
  padding: 4px 10px;
  font-size: 12px;
  font-weight: 600;
  color: #fff;
  background: rgba(0, 30, 15, 0.7);
  border-radius: 999px;
  backdrop-filter: blur(2px);
}
.model-shot::after {
  content: "点击查看大图 ↗";
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-weight: 600; color: #fff;
  background: rgba(0, 30, 15, 0.5);
  opacity: 0; transition: opacity .2s ease;
}
.model-shot:hover::after { opacity: 1; }

.model-hint {
  text-align: center; font-size: 12.5px; letter-spacing: .04em;
  color: var(--ink-soft); margin-top: 14px;
}

/* ===== 交互式 3D 模型查看器 ===== */
.model-viewer-wrap {
  max-width: 960px;
  margin: 18px auto 0;
}
.model-3d-iframe {
  display: block;
  width: 100%;
  max-width: 960px;
  height: 520px;
  margin: 0 auto;
  border: none;
  border-radius: 14px;
  box-shadow: var(--shadow-sm);
  background: linear-gradient(135deg, #f0f4f8, #e8ecf1);
}

/* ===== 模型展示视频（预留，当前未使用） ===== */
.model-video-showcase {
  text-align: center;
}
.model-video-showcase video {
  display: block;
  width: 100%;
  max-width: 720px;
  margin: 0 auto;
  border-radius: 14px;
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
}

.model-toggle-btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 14px 28px;
  font-size: 15px; font-weight: 600; color: #fff;
  background: var(--primary);
  border: none; border-radius: 999px;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(0, 177, 79, .25);
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.model-toggle-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 22px rgba(0, 177, 79, .32); background: #00a046; }
.model-toggle-btn:active { transform: translateY(0); }
.model-toggle-btn[disabled] { opacity: .6; cursor: wait; }
.model-toggle-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 50%;
  background: rgba(255, 255, 255, .25);
  font-size: 11px;
  transition: transform .25s ease;
}
.model-toggle-btn[aria-expanded="true"] .model-toggle-icon { transform: rotate(90deg); }

.model-3d-wrap {
  position: relative;
  width: 100%;
  max-width: 960px;
  height: 520px;
  margin: 18px auto 0;
  background: linear-gradient(135deg, #f0f4f8, #e8ecf1);
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
}
.model-3d-wrap[hidden] { display: none; }
.model-3d-iframe {
  display: block;
  width: 100%;
  max-width: 960px;
  height: 520px;
  margin: 0 auto;
  border: none;
  border-radius: 14px;
  box-shadow: var(--shadow-sm);
  background: linear-gradient(135deg, #f0f4f8, #e8ecf1);
}
.model-3d-bg {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  object-fit: contain; display: block;
  z-index: 1; pointer-events: none;
  background: linear-gradient(135deg, #f0f4f8, #e8ecf1);
}
.model-3d-canvas {
  position: absolute; inset: 0;
  width: 100% !important; height: 100% !important;
  display: block;
  z-index: 2;
  background: linear-gradient(135deg, #f0f4f8, #e8ecf1);
  touch-action: none;
  cursor: grab;
}
.model-3d-canvas:active { cursor: grabbing; }
.mv-overlay-icon {
  position: absolute; left: 50%; top: 50%;
  transform: translate(-50%, -50%);
  z-index: 3;
  pointer-events: none;
  opacity: 1;
  transition: opacity .6s ease;
  filter: drop-shadow(0 2px 8px rgba(0,0,0,.15));
  animation: mv-icon-bob 1.6s ease-in-out infinite;
}
@keyframes mv-icon-bob {
  0%, 100% { transform: translate(-50%, -52%) scale(1); }
  50%      { transform: translate(-50%, -48%) scale(1.05); }
}
model-viewer.model-3d-viewer {
  position: relative; display: block;
  width: 100%; height: 520px;
  z-index: 2; background: transparent;
  --poster-color: transparent;
}
model-viewer.model-3d-viewer::part(default-progress-bar) { display: none; }
.mv-loading {
  position: absolute; inset: 0; z-index: 5;
  display: flex; align-items: center; justify-content: center; gap: 12px;
  color: var(--ink-soft); font-size: 15px; font-weight: 600;
  background: rgba(243, 245, 248, 0.7);
}
.spinner {
  width: 22px; height: 22px; border-radius: 50%;
  border: 3px solid rgba(0, 177, 79, .25); border-top-color: var(--primary);
  animation: spin .8s linear infinite;
  display: inline-block;
}
@keyframes spin { to { transform: rotate(360deg); } }
.mv-error {
  position: absolute; left: 12px; right: 12px; bottom: 12px; z-index: 3;
  padding: 10px 14px; font-size: 13px; color: #b00;
  background: rgba(255, 240, 240, .92); border: 1px solid #f4c4c4; border-radius: 8px;
}
.mv-ok {
  position: absolute; left: 12px; top: 12px; z-index: 3;
  padding: 8px 14px; font-size: 13px; color: #fff;
  background: rgba(0, 177, 79, .9); border-radius: 8px;
  pointer-events: none;
}

@media (max-width: 720px) {
  .model-gallery { grid-template-columns: 1fr; }
  .model-3d-wrap, model-viewer.model-3d-viewer { height: 380px; }
  .model-3d-canvas { height: 380px !important; }
  .model-video-showcase video { max-width: 100%; }
}

/* ===== 滚动揭示动画 ===== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ===== 响应式 ===== */
@media (max-width: 920px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-visual { order: -1; }
  .about-grid, .adv-grid, .app-grid { grid-template-columns: repeat(2, 1fr); }
  .flow { grid-template-columns: repeat(2, 1fr); }
  .product, .contact-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .nav-links {
    position: fixed; top: 70px; left: 0; right: 0;
    flex-direction: column; gap: 0; background: var(--bg-card);
    border-bottom: 1px solid var(--line); padding: 8px 0;
    transform: translateY(-120%); transition: transform .3s; box-shadow: var(--shadow);
  }
  .nav-links.open { transform: translateY(0); }
  .nav-links a { padding: 14px 24px; }
  .nav-cta { display: none; }
  .nav-toggle { display: flex; }
  .about-grid, .adv-grid, .app-grid, .flow { grid-template-columns: 1fr; }
  .hero-stats { gap: 12px; }
  .section { padding: 72px 0; }
  .model-3d-iframe { height: 380px; }
  .video-hero { min-height: 88vh; padding: 100px 20px 80px; }
  .video-hero-actions { flex-direction: column; gap: 14px; width: 100%; max-width: 320px; }
  .video-hero-btn { width: 100%; justify-content: center; }
  .video-modal-content { border-radius: 12px; }
  .video-modal-close { top: -42px; width: 34px; height: 34px; }
}