:root {
  --bg: #08101f;
  --bg-soft: #0d1730;
  --card: rgba(17, 28, 56, 0.72);
  --card-strong: #111c38;
  --text: #eaf2ff;
  --muted: #9eb2d1;
  --line: rgba(255, 255, 255, 0.08);
  --primary: #47cfff;
  --primary-strong: #1ca8ff;
  --accent: #7c5cff;
  --success: #54e0a6;
  --shadow: 0 18px 48px rgba(0, 0, 0, 0.28);
  --radius: 22px;
  --container: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(71, 207, 255, 0.18), transparent 28%),
    radial-gradient(circle at 85% 10%, rgba(124, 92, 255, 0.15), transparent 24%),
    linear-gradient(180deg, #07101d 0%, #0a1324 32%, #0a1322 100%);
  line-height: 1.6;
}

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

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

button {
  font: inherit;
}

.container {
  width: min(var(--container), calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(7, 16, 29, 0.72);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.site-header.is-scrolled {
  background: rgba(7, 16, 29, 0.92);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 76px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand span {
  white-space: nowrap;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

.site-nav a,
.footer-links a {
  color: var(--muted);
  transition: color 0.2s ease;
}

.site-nav a:hover,
.footer-links a:hover {
  color: var(--text);
}

.menu-toggle {
  display: none;
  padding: 10px 14px;
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.03);
}

.hero {
  padding: 72px 0 42px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 40px;
  align-items: center;
}

.eyebrow,
.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 16px;
  padding: 8px 14px;
  color: #c8ebff;
  background: rgba(71, 207, 255, 0.09);
  border: 1px solid rgba(71, 207, 255, 0.16);
  border-radius: 999px;
  font-size: 14px;
}

.hero h1,
.section h2,
.section-alt h2 {
  margin: 0;
  line-height: 1.15;
}

.hero h1 {
  font-size: clamp(30px, 4.2vw, 48px);
  max-width: 12ch;
}

.lead {
  margin: 22px 0 0;
  font-size: 18px;
  color: var(--muted);
  max-width: 62ch;
}

.hero-actions,
.cta-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  padding: 0 22px;
  border-radius: 16px;
  font-weight: 700;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  color: #041220;
  background: linear-gradient(135deg, var(--primary), #8be9ff);
  box-shadow: 0 16px 32px rgba(71, 207, 255, 0.26);
}

.btn-secondary {
  color: var(--text);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--line);
}

.hero-note {
  margin: 18px 0 0;
  color: #b4c5df;
  font-size: 15px;
}

.hero-media {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-media::before {
  content: "";
  position: absolute;
  inset: -4% -3% auto auto;
  width: 160px;
  height: 160px;
  background: radial-gradient(circle, rgba(71, 207, 255, 0.28), transparent 68%);
  filter: blur(16px);
  pointer-events: none;
}

.hero-media img {
  width: auto;
  max-width: 100%;
  height: auto;
  border-radius: 28px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: var(--shadow);
  object-fit: contain;
}

.section,
.section-alt {
  padding: 44px 0;
}

.section-alt {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.02), rgba(255, 255, 255, 0.03));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.section-head {
  max-width: 760px;
  margin-bottom: 28px;
}

.section-head h2,
.metrics-copy h2 {
  font-size: clamp(28px, 4vw, 42px);
}

.section-head p,
.metrics-copy p,
.guide-grid p,
.timeline li,
.download-card p,
.faq-item p,
.site-footer p {
  color: var(--muted);
}

.feature-grid,
.download-grid {
  display: grid;
  gap: 18px;
}

.feature-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.card,
.download-card,
.stat,
.faq-item,
.code-line {
  border: 1px solid var(--line);
  background: var(--card);
  box-shadow: var(--shadow);
}

.card {
  padding: 24px;
  border-radius: var(--radius);
}

.icon,
.platform-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  margin-bottom: 16px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.05);
  font-size: 24px;
}

.card h3,
.download-card h3,
.steps h3 {
  margin: 0 0 10px;
  font-size: 20px;
}

.card p,
.download-card p,
.faq-item p,
.steps p {
  margin: 0;
}

.metrics-grid,
.timeline-grid,
.guide-grid,
.footer-grid {
  display: grid;
  gap: 28px;
}

.metrics-grid,
.timeline-grid {
  grid-template-columns: 1fr 1fr;
  align-items: center;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.stat {
  padding: 24px;
  border-radius: 20px;
}

.stat strong {
  display: block;
  margin-bottom: 8px;
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1;
}

.tip {
  margin-top: 18px;
  padding-left: 16px;
  border-left: 3px solid rgba(71, 207, 255, 0.45);
}

.download-grid {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.download-card {
  padding: 22px;
  border-radius: 20px;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.download-card:hover {
  transform: translateY(-2px);
  border-color: rgba(71, 207, 255, 0.32);
}

.more-link {
  margin: 18px 0 0;
}

.more-link a {
  color: #7edfff;
}

.timeline {
  margin: 0;
  padding-left: 18px;
}

.timeline li + li {
  margin-top: 16px;
}

.guide-grid {
  grid-template-columns: 1fr 1fr;
}

.code-line {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 0 16px;
  border-radius: 14px;
}

.steps {
  margin: 0;
  padding-left: 22px;
}

.steps li + li {
  margin-top: 18px;
}

.cta-strip {
  margin-top: 24px;
}

.faq-list {
  display: grid;
  gap: 16px;
}

.faq-item {
  padding: 0;
  border-radius: 20px;
  overflow: hidden;
}

.faq-item summary {
  position: relative;
  padding: 20px 56px 20px 22px;
  cursor: pointer;
  list-style: none;
  font-weight: 600;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  position: absolute;
  top: 50%;
  right: 20px;
  transform: translateY(-50%);
  color: var(--primary);
  font-size: 24px;
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item p {
  margin: 0;
  padding: 0 22px 22px;
}

.site-footer {
  padding: 34px 0 18px;
}

.footer-grid {
  grid-template-columns: 1.4fr 0.6fr;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
}

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

.footer-links {
  display: grid;
  gap: 12px;
  justify-items: start;
  align-content: start;
}

.footer-bottom {
  padding-top: 18px;
}

.footer-bottom p {
  margin: 0;
  font-size: 14px;
}

@media (max-width: 1100px) {
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .download-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 860px) {
  .menu-toggle {
    display: inline-flex;
  }

  .site-nav {
    position: absolute;
    top: calc(100% + 10px);
    right: 16px;
    left: 16px;
    display: none;
    flex-direction: column;
    align-items: flex-start;
    padding: 16px;
    background: rgba(11, 18, 33, 0.96);
    border: 1px solid var(--line);
    border-radius: 18px;
    box-shadow: var(--shadow);
  }

  .site-nav.is-open {
    display: flex;
  }

  .hero-grid,
  .metrics-grid,
  .timeline-grid,
  .guide-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 48px;
  }

  .hero h1 {
    max-width: none;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(var(--container), calc(100% - 24px));
  }

  .section,
  .section-alt {
    padding: 34px 0;
  }

  .feature-grid,
  .download-grid,
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .header-inner {
    min-height: 68px;
  }

  .hero-actions,
  .cta-strip {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}