/* ===== Reset & Variables ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #3B82F6;
  --primary-dark: #2563EB;
  --primary-light: #60A5FA;
  --primary-bg: #EFF6FF;
  --primary-gradient: linear-gradient(135deg, #3B82F6, #1D4ED8);
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --bg-dark: #1e1b4b;
  --text: #1e293b;
  --text-body: #475569;
  --text-muted: #94a3b8;
  --border: #e2e8f0;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow: 0 4px 24px rgba(0,0,0,0.07);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.1);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-xs: 6px;
}

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Animations ===== */
.feature-card,
.scenario-card,
.step-card,
.stat-item,
.download-card {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.feature-card.visible,
.scenario-card.visible,
.step-card.visible,
.stat-item.visible,
.download-card.visible {
  opacity: 1;
  transform: translateY(0);
}

/* stagger */
.feature-card:nth-child(2), .stat-item:nth-child(3) { transition-delay: 0.08s; }
.feature-card:nth-child(3), .stat-item:nth-child(5) { transition-delay: 0.16s; }
.feature-card:nth-child(4), .stat-item:nth-child(7) { transition-delay: 0.24s; }
.feature-card:nth-child(5) { transition-delay: 0.32s; }
.feature-card:nth-child(6) { transition-delay: 0.4s; }
.download-card:nth-child(2) { transition-delay: 0.1s; }

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.logo-mark {
  flex-shrink: 0;
}

.logo-text {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-body);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover { color: var(--primary); }

.btn-nav {
  display: inline-flex;
  align-items: center;
  padding: 8px 20px;
  border-radius: var(--radius-xs);
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  background: var(--primary);
  color: #fff !important;
  transition: background 0.2s, transform 0.15s;
}

.btn-nav:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  cursor: pointer;
  padding: 4px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
  border: 2px solid transparent;
  text-align: center;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
  background: var(--primary-dark);
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.4);
  transform: translateY(-2px);
}

.btn-outline-dark {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.btn-outline-dark:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-bg);
}

.btn-white {
  background: #fff;
  color: var(--primary);
}

.btn-white:hover {
  background: #f1f5f9;
  transform: translateY(-2px);
}

.btn-outline-white {
  background: transparent;
  border-color: rgba(255,255,255,0.4);
  color: #fff;
}

.btn-outline-white:hover {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.7);
}

.btn-lg { padding: 14px 36px; font-size: 1rem; }

/* ===== Hero ===== */
.hero {
  padding: 140px 0 80px;
  background: linear-gradient(180deg, var(--primary-bg) 0%, var(--bg) 100%);
  overflow: hidden;
}

.hero-inner {
  display: flex;
  align-items: center;
  gap: 60px;
}

.hero-text {
  flex: 1;
  min-width: 0;
}

.hero h1 {
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 32px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.hero-trust {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-body);
  font-weight: 500;
}

/* Hero Visual */
.hero-visual {
  flex: 0 0 380px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-globe {
  position: relative;
  width: 320px;
  height: 320px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.globe-ring {
  position: absolute;
  border-radius: 50%;
  border: 1.5px solid rgba(59, 130, 246, 0.15);
}

.ring-1 {
  width: 200px;
  height: 200px;
  animation: pulse-ring 4s ease-in-out infinite;
}

.ring-2 {
  width: 260px;
  height: 260px;
  border-color: rgba(59, 130, 246, 0.1);
  animation: pulse-ring 4s ease-in-out infinite 0.8s;
}

.ring-3 {
  width: 320px;
  height: 320px;
  border-color: rgba(59, 130, 246, 0.06);
  animation: pulse-ring 4s ease-in-out infinite 1.6s;
}

@keyframes pulse-ring {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.04); opacity: 0.7; }
}

.globe-shield {
  position: relative;
  z-index: 2;
  filter: drop-shadow(0 8px 32px rgba(59, 130, 246, 0.3));
}

.globe-dot {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--primary);
  opacity: 0.5;
  animation: float-dot 3s ease-in-out infinite;
}

.dot-1 { top: 40px; left: 60px; animation-delay: 0s; }
.dot-2 { top: 80px; right: 30px; animation-delay: 0.5s; width: 8px; height: 8px; }
.dot-3 { bottom: 60px; left: 40px; animation-delay: 1s; width: 6px; height: 6px; }
.dot-4 { bottom: 90px; right: 50px; animation-delay: 1.5s; }
.dot-5 { top: 140px; left: 20px; animation-delay: 2s; width: 7px; height: 7px; }

@keyframes float-dot {
  0%, 100% { transform: translateY(0); opacity: 0.5; }
  50% { transform: translateY(-8px); opacity: 0.9; }
}

/* ===== Stats ===== */
.stats {
  padding: 48px 0;
  background: var(--bg);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.stats-grid {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
}

.stat-item {
  flex: 1;
  text-align: center;
  padding: 8px 0;
}

.stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-top: 4px;
}

.stat-divider {
  width: 1px;
  height: 40px;
  background: var(--border);
  flex-shrink: 0;
}

/* ===== Section Header ===== */
.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background: var(--primary-bg);
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text);
  margin-bottom: 12px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 540px;
  margin: 0 auto;
}

/* ===== Features ===== */
.features {
  padding: 100px 0;
  background: var(--bg-alt);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 28px;
  transition: box-shadow 0.3s, transform 0.3s, opacity 0.6s, border-color 0.3s;
}

.feature-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-4px);
  border-color: rgba(59, 130, 246, 0.2);
}

.feature-icon {
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text);
}

.feature-card p {
  font-size: 0.925rem;
  color: var(--text-body);
  line-height: 1.7;
}

/* ===== Scenarios ===== */
.scenarios {
  padding: 100px 0;
  background: var(--bg);
}

.scenarios-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.scenario-card {
  text-align: center;
  padding: 40px 20px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  transition: box-shadow 0.3s, transform 0.3s, opacity 0.6s;
  background: var(--bg);
}

.scenario-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}

.scenario-icon {
  margin-bottom: 20px;
}

.scenario-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text);
}

.scenario-card p {
  font-size: 0.875rem;
  color: var(--text-body);
  line-height: 1.7;
}

.scenario-highlight {
  position: relative;
  border-color: var(--primary);
  background: var(--primary-bg);
}

.scenario-highlight:hover {
  border-color: var(--primary-dark);
}

.scenario-badge {
  position: absolute;
  top: 12px;
  right: 12px;
  font-size: 0.7rem;
  font-weight: 700;
  color: #fff;
  background: var(--primary);
  padding: 2px 10px;
  border-radius: 12px;
  letter-spacing: 0.04em;
}

/* ===== Steps ===== */
.steps {
  padding: 100px 0;
  background: var(--bg-alt);
}

.steps-grid {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
}

.step-card {
  flex: 0 0 240px;
  text-align: center;
  padding: 32px 20px;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary-gradient);
  color: #fff;
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 20px;
}

.step-icon {
  margin-bottom: 16px;
}

.step-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}

.step-card p {
  font-size: 0.875rem;
  color: var(--text-body);
}

.step-connector {
  display: flex;
  align-items: center;
  padding-top: 80px;
}

/* ===== Download ===== */
.download {
  padding: 100px 0;
  background: var(--bg);
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  max-width: 900px;
  margin: 0 auto;
}

.download-card {
  background: var(--bg);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 44px 32px;
  text-align: center;
  transition: box-shadow 0.3s, transform 0.3s, border-color 0.3s, opacity 0.6s;
}

.download-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-6px);
  border-color: var(--primary-light);
}

.platform-icon {
  margin-bottom: 20px;
}

.download-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}

.download-card p {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.download-card .btn { width: 100%; }

.download-more {
  text-align: center;
  margin-top: 28px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ===== FAQ ===== */
.faq {
  padding: 100px 0;
  background: var(--bg-alt);
}

.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--border);
}

.faq-item:first-child {
  border-top: 1px solid var(--border);
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 20px 0;
  border: none;
  background: none;
  cursor: pointer;
  text-align: left;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  font-family: inherit;
  transition: color 0.2s;
}

.faq-question:hover { color: var(--primary); }

.faq-chevron {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: transform 0.3s ease;
}

.faq-item.open .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
}

.faq-item.open .faq-answer {
  max-height: 200px;
}

.faq-answer p {
  padding-bottom: 20px;
  font-size: 0.925rem;
  color: var(--text-body);
  line-height: 1.8;
}

.faq-more {
  text-align: center;
  margin-top: 40px;
}

.faq-more p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.faq-more a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
}

.faq-more a:hover { text-decoration: underline; }

/* ===== CTA ===== */
.cta {
  padding: 80px 0;
  background: var(--primary-gradient);
  text-align: center;
}

.cta h2 {
  font-size: 2rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 12px;
}

.cta p {
  font-size: 1.05rem;
  color: rgba(255,255,255,0.8);
  margin-bottom: 32px;
}

.cta-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Footer ===== */
.footer {
  background: #fafbfc;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  flex-direction: column;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 28px 0;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
}

.footer-links {
  display: flex;
  gap: 28px;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.2s;
}

.footer-links a:hover { color: var(--primary); }

.footer-bottom {
  padding: 16px 0;
  border-top: 1px solid var(--border);
}

.footer-bottom p {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

/* ===== Mobile ===== */
@media (max-width: 900px) {
  .hero-inner {
    flex-direction: column;
    text-align: center;
  }

  .hero h1 { font-size: 2.4rem; }

  .hero-actions { justify-content: center; }
  .hero-trust { justify-content: center; }

  .hero-visual { flex: none; margin-top: 20px; }
  .hero-globe { width: 260px; height: 260px; }
  .ring-1 { width: 160px; height: 160px; }
  .ring-2 { width: 210px; height: 210px; }
  .ring-3 { width: 260px; height: 260px; }

  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .scenarios-grid { grid-template-columns: repeat(2, 1fr); }

  .steps-grid { flex-wrap: wrap; gap: 0; }
  .step-connector { display: none; }
  .step-card { flex: 0 0 calc(33.33% - 16px); }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(255,255,255,0.97);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    padding: 20px 24px;
    gap: 12px;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  }

  .nav-links a { font-size: 1rem; padding: 8px 0; }
  .nav-open { display: flex; }
  .mobile-menu-btn { display: block; }

  .hero { padding: 110px 0 60px; }
  .hero h1 { font-size: 2rem; }
  .hero-subtitle { font-size: 1rem; }
  .hero-subtitle br { display: none; }

  .stats-grid { flex-wrap: wrap; gap: 0; }
  .stat-item { flex: 0 0 50%; padding: 16px 0; }
  .stat-divider { display: none; }

  .section-title { font-size: 1.75rem; }
  .section-header { margin-bottom: 40px; }

  .features { padding: 72px 0; }
  .scenarios { padding: 72px 0; }
  .steps { padding: 72px 0; }
  .download { padding: 72px 0; }
  .faq { padding: 72px 0; }

  .download-grid { grid-template-columns: 1fr; max-width: 380px; }

  .footer-top {
    flex-direction: column;
    gap: 16px;
    align-items: center;
  }

  .footer-links {
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
  }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.75rem; }
  .hero-globe { width: 220px; height: 220px; }
  .ring-1 { width: 140px; height: 140px; }
  .ring-2 { width: 180px; height: 180px; }
  .ring-3 { width: 220px; height: 220px; }
  .globe-shield svg { width: 60px; height: 72px; }

  .features-grid { grid-template-columns: 1fr; }
  .scenarios-grid { grid-template-columns: 1fr; }
  .step-card { flex: 0 0 100%; }

  .hero-trust { flex-direction: column; gap: 10px; align-items: center; }
  .stat-number { font-size: 1.6rem; }
  .cta h2 { font-size: 1.5rem; }
}