:root {
  --brand: #409eff;
  --brand-2: #6366f1;
  --brand-3: #22d3ee;
  --bg: #ffffff;
  --bg-soft: #f6f8fc;
  --text: #1f2937;
  --text-soft: #4b5563;
  --text-mute: #6b7280;
  --border: #e5e7eb;
  --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 24px 60px rgba(15, 23, 42, 0.12);
  --radius: 14px;
  --radius-sm: 10px;
  --grad: linear-gradient(120deg, #4f8cff 0%, #6366f1 50%, #22d3ee 100%);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  color: var(--text);
  background: var(--bg);
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, "Segoe UI", sans-serif;
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

a { color: inherit; text-decoration: none; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img { max-width: 100%; display: block; }

.container {
  width: min(1180px, 92%);
  margin: 0 auto;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease, color .2s ease;
}
.btn-lg { padding: 14px 30px; font-size: 15.5px; }
.btn-primary {
  background: var(--grad);
  color: #fff;
  box-shadow: 0 6px 18px rgba(79, 140, 255, 0.35);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 10px 26px rgba(79, 140, 255, 0.45); }
.btn-outline {
  border-color: var(--border);
  background: #fff;
  color: var(--text);
}
.btn-outline:hover { border-color: var(--brand); color: var(--brand); }
.btn-ghost { color: var(--text-soft); }
.btn-ghost:hover { color: var(--brand); }

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.78);
  backdrop-filter: saturate(150%) blur(12px);
  -webkit-backdrop-filter: saturate(150%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s ease, box-shadow .25s ease;
}
.nav.scrolled {
  border-bottom-color: var(--border);
  box-shadow: var(--shadow-sm);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}
.brand-logo {
  width: 30px; height: 30px;
  object-fit: contain;
}
.brand-name {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.5px;
}
.brand-accent {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.brand-tag {
  font-size: 14px;
  line-height: 1.4;
  color: var(--text-mute);
  padding: 3px 9px;
  border-radius: 6px;
  background: var(--bg-soft);
}
.nav-links {
  display: flex;
  gap: 28px;
}
.nav-links a {
  font-size: 14px;
  color: var(--text-soft);
  position: relative;
  padding: 6px 0;
}
.nav-links a:hover { color: var(--brand); }
.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: 80px 0 96px;
  background:
    linear-gradient(135deg, rgba(64, 158, 255, 0.12) 0%, rgba(99, 102, 241, 0.08) 36%, rgba(255, 255, 255, 0.96) 78%),
    linear-gradient(180deg, #f7faff 0%, #ffffff 72%);
  border-bottom: 1px solid rgba(229, 231, 235, 0.9);
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    linear-gradient(110deg, transparent 0%, rgba(64, 158, 255, 0.08) 34%, transparent 58%),
    linear-gradient(rgba(64, 158, 255, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(64, 158, 255, 0.055) 1px, transparent 1px);
  background-size: auto, 44px 44px, 44px 44px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.72), transparent 82%);
}
.hero-bg {
  position: absolute;
  inset: -200px 0 auto 0;
  height: 700px;
  background:
    radial-gradient(600px 320px at 15% 30%, rgba(79, 140, 255, 0.22), transparent 60%),
    radial-gradient(540px 320px at 85% 20%, rgba(99, 102, 241, 0.20), transparent 60%),
    radial-gradient(420px 260px at 60% 75%, rgba(34, 211, 238, 0.18), transparent 60%);
  z-index: 0;
  filter: blur(0.5px);
  pointer-events: none;
}
.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 48px;
  align-items: center;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 9px 20px;
  border-radius: 999px;
  background: linear-gradient(120deg, rgba(79, 140, 255, 0.16), rgba(99, 102, 241, 0.16) 55%, rgba(34, 211, 238, 0.16));
  color: #4338ca;
  font-size: 14.5px;
  font-weight: 600;
  letter-spacing: 0.4px;
  margin-bottom: 22px;
  border: 1px solid rgba(99, 102, 241, 0.32);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.18);
}
.hero-badge .dot {
  width: 8px; height: 8px;
  background: #6366f1;
  border-radius: 50%;
  box-shadow: 0 0 0 5px rgba(99, 102, 241, 0.18);
  animation: badge-blink 1.6s ease-in-out infinite;
}
@keyframes badge-blink {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.55; transform: scale(0.85); }
}
.hero-title {
  font-size: 46px;
  line-height: 1.22;
  margin: 0 0 18px;
  letter-spacing: -0.5px;
  font-weight: 600;
  word-break: keep-all;
}
.grad {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  white-space: nowrap;
}
.hero-sub {
  font-size: 17px;
  color: var(--text-soft);
  margin: 0 0 28px;
  max-width: 560px;
}
.hero-actions {
  display: flex;
  gap: 14px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}
.hero-meta {
  display: flex;
  gap: 36px;
  padding-top: 22px;
  border-top: 1px dashed var(--border);
}
.hero-meta li {
  display: flex;
  flex-direction: column;
}
.hero-meta strong {
  font-size: 24px;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-meta span {
  font-size: 13px;
  color: var(--text-mute);
  margin-top: 2px;
}

/* ---------- Hero Visual (mock window) ---------- */
.hero-visual {
  position: relative;
}
.window {
  background: #fff;
  border-radius: 18px;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  transform: perspective(1200px) rotateY(-3deg) rotateX(2deg);
}
.window-bar {
  height: 38px;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 14px;
  background: #f8fafc;
  border-bottom: 1px solid var(--border);
  position: relative;
}
.window-bar span {
  width: 11px; height: 11px;
  border-radius: 50%;
  background: #f87171;
}
.window-bar span:nth-child(2) { background: #fbbf24; }
.window-bar span:nth-child(3) { background: #34d399; }
.window-bar em {
  position: absolute;
  left: 50%; transform: translateX(-50%);
  font-style: normal;
  font-size: 12px;
  color: var(--text-mute);
}
.window-body {
  display: grid;
  grid-template-columns: 168px 1fr;
  height: 380px;
}
.mock-sidebar {
  background: #f9fafb;
  border-right: 1px solid var(--border);
  padding: 14px 10px;
  font-size: 12.5px;
  color: var(--text-soft);
  overflow: hidden;
}
.mock-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
}
.mock-logo i {
  display: inline-block;
  width: 18px; height: 18px;
  border-radius: 6px;
  background: var(--grad);
}
.mock-item {
  padding: 7px 10px;
  border-radius: 8px;
  margin-bottom: 3px;
  cursor: default;
}
.mock-item.active {
  background: rgba(64, 158, 255, 0.12);
  color: var(--brand);
  font-weight: 500;
}
.mock-section {
  font-size: 11.5px;
  color: var(--text-mute);
  margin: 12px 6px 6px;
}
.mock-history {
  padding: 6px 10px;
  border-radius: 6px;
  color: var(--text-mute);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.mock-chat {
  padding: 20px 22px;
  background: #fff;
  display: flex;
  flex-direction: column;
  gap: 12px;
  overflow: hidden;
}
.bubble {
  max-width: 78%;
  padding: 10px 14px;
  border-radius: 14px;
  font-size: 13.5px;
  line-height: 1.5;
}
.bubble.bot {
  background: #f3f4f6;
  color: var(--text);
  border-top-left-radius: 4px;
  align-self: flex-start;
}
.bubble.user {
  background: var(--grad);
  color: #fff;
  border-top-right-radius: 4px;
  align-self: flex-end;
}
.bubble.typing {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.dots {
  display: inline-flex;
  gap: 3px;
  margin-left: 4px;
}
.dots i {
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--brand);
  display: inline-block;
  animation: blink 1.4s infinite both;
}
.dots i:nth-child(2) { animation-delay: 0.2s; }
.dots i:nth-child(3) { animation-delay: 0.4s; }
@keyframes blink {
  0%, 80%, 100% { opacity: .25; transform: translateY(0); }
  40% { opacity: 1; transform: translateY(-2px); }
}

/* ---------- 数字人通话浮卡 ---------- */
.call-card {
  position: absolute;
  right: -24px;
  bottom: -28px;
  display: flex;
  align-items: center;
  gap: 12px;
  background: #fff;
  border-radius: 14px;
  box-shadow: var(--shadow-lg);
  padding: 10px 16px 10px 12px;
  border: 1px solid var(--border);
  z-index: 2;
  animation: call-float 5s ease-in-out infinite;
}
.call-avatar {
  width: 40px; height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, #6366f1, #22d3ee);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  position: relative;
  flex-shrink: 0;
}
.call-emoji { font-size: 18px; line-height: 1; }
.call-pulse {
  position: absolute;
  inset: -5px;
  border-radius: 50%;
  border: 2px solid rgba(99, 102, 241, 0.55);
  animation: call-pulse 1.8s ease-out infinite;
}
.call-info { display: flex; flex-direction: column; gap: 4px; }
.call-name { font-size: 13px; font-weight: 600; color: var(--text); white-space: nowrap; }
.call-meta { display: flex; align-items: center; gap: 6px; font-size: 11px; color: var(--text-mute); }
.call-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: #10b981;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.18);
}
.call-wave {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  height: 14px;
}
.call-wave i {
  display: inline-block;
  width: 2.5px;
  height: 4px;
  background: var(--brand);
  border-radius: 2px;
  animation: call-wave 1.2s ease-in-out infinite;
}
.call-wave i:nth-child(2) { animation-delay: 0.15s; }
.call-wave i:nth-child(3) { animation-delay: 0.3s; }
.call-wave i:nth-child(4) { animation-delay: 0.45s; }
.call-wave i:nth-child(5) { animation-delay: 0.6s; }
.call-time { font-variant-numeric: tabular-nums; }
@keyframes call-wave {
  0%, 100% { height: 4px; }
  50% { height: 13px; }
}
@keyframes call-pulse {
  0% { transform: scale(1); opacity: 0.75; }
  100% { transform: scale(1.55); opacity: 0; }
}
@keyframes call-float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-6px); }
}

.float-card {
  position: absolute;
  background: #fff;
  border-radius: 12px;
  box-shadow: var(--shadow-md);
  padding: 12px 14px;
  border: 1px solid var(--border);
  animation: float 5s ease-in-out infinite;
}
.float-card .fc-title { font-size: 13px; font-weight: 600; margin-bottom: 2px; }
.float-card .fc-desc { font-size: 12px; color: var(--text-mute); }
.card-1 { left: -20px; top: 22%; }
.card-2 { right: -10px; bottom: 12%; animation-delay: 1.5s; }
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

/* ---------- Sections ---------- */
.section {
  padding: 88px 0;
}
.section-alt {
  background: var(--bg-soft);
}
.section-head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px;
}
.kicker {
  display: inline-block;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--brand);
  background: rgba(64, 158, 255, 0.10);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 16px;
}
.section-head h2 {
  font-size: 34px;
  margin: 0 0 12px;
  font-weight: 700;
  letter-spacing: -0.3px;
}
.section-head p {
  color: var(--text-soft);
  font-size: 16px;
  margin: 0;
}

.grid {
  display: grid;
  gap: 22px;
}
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* Feature cards */
.feature {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 22px;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.feature:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: transparent;
}
.feature-icon {
  width: 52px; height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  margin-bottom: 16px;
}
.ic-1 { background: linear-gradient(135deg, #4f8cff, #6366f1); }
.ic-2 { background: linear-gradient(135deg, #22d3ee, #3b82f6); }
.ic-3 { background: linear-gradient(135deg, #f59e0b, #ef4444); }
.ic-4 { background: linear-gradient(135deg, #10b981, #06b6d4); }
.feature h3 {
  font-size: 18px;
  margin: 0 0 8px;
}
.feature p {
  color: var(--text-soft);
  font-size: 14px;
  margin: 0 0 14px;
}
.feature ul li {
  font-size: 13.5px;
  color: var(--text-mute);
  padding-left: 18px;
  position: relative;
  margin-bottom: 4px;
}
.feature ul li::before {
  content: "";
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--brand);
  position: absolute;
  left: 4px; top: 9px;
}

/* Scenes */
.scene {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow-sm);
  transition: transform .25s ease, box-shadow .25s ease;
}
.scene:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.scene-emoji { font-size: 30px; margin-bottom: 10px; }
.scene h3 { font-size: 17px; margin: 0 0 8px; }
.scene p { font-size: 14px; color: var(--text-soft); margin: 0; }

/* Model chips */
.models {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  max-width: 880px;
  margin: 0 auto;
}
.model-chip {
  padding: 12px 22px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-soft);
  box-shadow: var(--shadow-sm);
  transition: transform .2s ease, color .2s ease, border-color .2s ease;
}
.model-chip:hover {
  transform: translateY(-2px);
  color: var(--brand);
  border-color: var(--brand);
}

/* Steps */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
  counter-reset: step;
}
.steps li {
  background: #fff;
  border-radius: var(--radius);
  padding: 24px 20px;
  position: relative;
  box-shadow: var(--shadow-sm);
  border-top: 3px solid transparent;
  background-image: linear-gradient(#fff, #fff), var(--grad);
  background-origin: border-box;
  background-clip: padding-box, border-box;
}
.step-no {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 10px;
  letter-spacing: 1px;
}
.steps h3 { margin: 0 0 6px; font-size: 16px; }
.steps p { margin: 0; font-size: 13.5px; color: var(--text-soft); }

/* Stack cards */
.stack-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 24px;
  transition: box-shadow .25s ease, transform .25s ease;
}
.stack-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.stack-card h3 {
  font-size: 17px;
  margin: 0 0 8px;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 700;
}
.stack-card p { color: var(--text-soft); margin: 0; font-size: 14.5px; }

/* CTA */
.cta {
  position: relative;
  overflow: hidden;
  background: linear-gradient(120deg, #4f8cff 0%, #6366f1 55%, #22d3ee 100%);
  color: #fff;
  padding: 80px 0;
}
.cta::before, .cta::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  opacity: 0.35;
  filter: blur(60px);
}
.cta::before { width: 320px; height: 320px; background: #fff; top: -120px; left: -80px; }
.cta::after { width: 360px; height: 360px; background: #c7d2fe; bottom: -160px; right: -100px; }
.cta-inner {
  position: relative;
  display: grid;
  grid-template-columns: 1.1fr auto;
  gap: 56px;
  align-items: center;
}
.cta-text { color: #fff; }
.cta h2 {
  font-size: 34px;
  margin: 0 0 14px;
  font-weight: 700;
}
.cta p { font-size: 16px; opacity: .92; margin: 0 0 20px; max-width: 520px; }
.cta-points {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 14.5px;
  opacity: 0.92;
}
.cta-qr { display: flex; justify-content: flex-end; }
.qr-img {
  width: 300px;
  height: auto;
  display: block;
  border-radius: 16px;
  box-shadow: 0 22px 60px rgba(0, 0, 0, 0.28);
}

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  background: #fff;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  text-align: center;
}
.copyright-sep { margin: 0 6px; color: var(--text-mute); opacity: 0.6; }
.copyright-link { color: var(--text-mute); transition: color .2s ease; }
.copyright-link:hover { color: var(--brand); }
.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  color: var(--text-soft);
}
.footer-brand img { width: 22px; height: 22px; object-fit: contain; }
.copyright { font-size: 13px; color: var(--text-mute); margin: 0; }

/* Reveal-on-scroll */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .7s ease, transform .7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive */
@media (max-width: 1024px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-title { font-size: 42px; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .window { transform: none; }
  .call-card { right: 8px; bottom: -22px; }
  .cta-inner { grid-template-columns: 1fr; gap: 32px; text-align: center; }
  .cta-text p, .cta-points { margin-left: auto; margin-right: auto; }
  .cta-points { align-items: center; }
  .cta-qr { justify-content: center; }
}
@media (max-width: 720px) {
  .nav-links { display: none; }
  .hero { padding: 56px 0 64px; }
  .hero-title { font-size: 32px; }
  .hero-sub { font-size: 15px; }
  .hero-meta { gap: 24px; }
  .section { padding: 64px 0; }
  .section-head h2 { font-size: 26px; }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .cta h2 { font-size: 26px; }
  .brand-tag { display: none; }
  .call-card { display: none; }
}