:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --surface-2: #eef5ff;
  --text: #111827;
  --muted: #4b5563;
  --line: #d8e2ef;
  --primary: #116dff;
  --primary-strong: #0754d6;
  --primary-soft: #e7f0ff;
  --accent: #12b886;
  --warning: #9a5b00;
  --shadow: 0 18px 48px rgba(21, 37, 66, 0.12);
  --radius: 8px;
  --shell: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.65;
  letter-spacing: 0;
}

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

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 3px solid rgba(17, 109, 255, 0.45);
  outline-offset: 3px;
}

svg {
  display: block;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.8;
}

.shell {
  width: min(100% - 32px, var(--shell));
  margin-inline: auto;
}

.narrow {
  max-width: 820px;
}

.skip-link {
  position: fixed;
  left: 16px;
  top: 16px;
  z-index: 1000;
  transform: translateY(-160%);
  border-radius: 6px;
  background: var(--text);
  color: white;
  padding: 10px 14px;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(246, 248, 251, 0.92);
  border-bottom: 1px solid rgba(216, 226, 239, 0.8);
  backdrop-filter: blur(12px);
}

.nav {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  font-weight: 800;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--primary), #30a2ff);
  color: #fff;
  font-weight: 900;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  border-radius: 8px;
  color: var(--muted);
  font-weight: 650;
  padding: 0 14px;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  background: var(--primary-soft);
  color: var(--primary-strong);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
}

.nav-toggle svg {
  width: 22px;
  margin: auto;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

.hero {
  min-height: calc(100dvh - 72px);
  display: grid;
  align-items: center;
  padding: 64px 0 40px;
  background:
    radial-gradient(circle at 88% 20%, rgba(18, 184, 134, 0.16), transparent 34%),
    linear-gradient(180deg, #ffffff 0%, var(--bg) 100%);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(340px, 0.98fr);
  gap: 48px;
  align-items: center;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--primary-strong);
  font-size: 14px;
  font-weight: 800;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 780px;
  margin-bottom: 20px;
  font-size: clamp(36px, 7vw, 66px);
  line-height: 1.08;
}

h2 {
  margin-bottom: 12px;
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.18;
}

h3 {
  margin-bottom: 10px;
  font-size: 20px;
  line-height: 1.35;
}

.hero-text {
  max-width: 660px;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 18px;
}

.button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  font-weight: 800;
  padding: 12px 20px;
  transition: transform 180ms ease, background 180ms ease, border-color 180ms ease;
}

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

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

.primary:hover {
  background: var(--primary-strong);
}

.secondary {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text);
}

.notice {
  color: var(--warning);
  font-size: 14px;
  font-weight: 700;
}

.product-visual {
  overflow: hidden;
  border: 1px solid rgba(17, 109, 255, 0.2);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.visual-topbar {
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--line);
  padding: 14px 16px;
}

.visual-topbar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #9fb4d0;
}

.visual-body {
  display: grid;
  grid-template-columns: 86px 1fr;
  min-height: 420px;
}

.visual-sidebar {
  display: grid;
  align-content: start;
  gap: 14px;
  background: #102a5c;
  padding: 22px;
}

.visual-sidebar b {
  width: 42px;
  height: 42px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.18);
}

.visual-panel {
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: 22px;
  padding: 28px;
}

.visual-stat {
  display: flex;
  align-items: end;
  justify-content: space-between;
  border-radius: 8px;
  background: var(--primary-soft);
  padding: 22px;
}

.visual-stat strong {
  color: var(--primary-strong);
  font-size: 48px;
  line-height: 1;
}

.visual-stat span {
  color: var(--muted);
  font-weight: 700;
}

.visual-chart {
  min-height: 160px;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  align-items: end;
  gap: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 18px;
}

.visual-chart span {
  border-radius: 6px 6px 0 0;
  background: linear-gradient(180deg, #39c5bb, var(--primary));
}

.visual-list {
  display: grid;
  gap: 10px;
}

.visual-list i {
  display: block;
  height: 16px;
  border-radius: 999px;
  background: #dbe7f7;
}

.visual-list i:nth-child(2) {
  width: 78%;
}

.visual-list i:nth-child(3) {
  width: 54%;
}

.section {
  padding: 82px 0;
}

.section-head {
  max-width: 760px;
  margin-bottom: 34px;
}

.section-head p:not(.eyebrow),
.two-column p,
.feature-card p,
.scene-list p,
.download-panel p,
.checklist,
.version-grid p,
.faq-list p,
.site-footer p {
  color: var(--muted);
}

.feature-grid,
.version-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.feature-card,
.version-grid article,
.scene-list article,
.download-panel,
.checklist {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  padding: 24px;
}

.feature-card svg {
  width: 34px;
  height: 34px;
  margin-bottom: 18px;
  color: var(--primary);
}

.band {
  background: var(--surface-2);
}

.two-column {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 42px;
}

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

.faq-list {
  display: grid;
  gap: 12px;
}

details {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  padding: 18px 20px;
}

summary {
  cursor: pointer;
  font-weight: 800;
}

summary::marker {
  color: var(--primary);
}

details p {
  margin: 12px 0 0;
}

.subhero {
  padding: 92px 0 54px;
  background: linear-gradient(180deg, #ffffff 0%, var(--surface-2) 100%);
}

.subhero h1 {
  font-size: clamp(34px, 6vw, 58px);
}

.subhero p:not(.eyebrow) {
  color: var(--muted);
  font-size: 18px;
}

.download-layout {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 22px;
  align-items: start;
}

.safe-box {
  display: grid;
  gap: 6px;
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  background: #effcf6;
  padding: 16px 18px;
}

.safe-box strong {
  color: #087f5b;
}

.checklist ul {
  margin: 0;
  padding-left: 20px;
}

.checklist li + li {
  margin-top: 10px;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #081a3a;
  color: #fff;
  padding: 40px 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 28px;
  align-items: start;
}

.footer-brand {
  margin-bottom: 12px;
}

.site-footer p {
  max-width: 560px;
  margin-bottom: 0;
  color: #c8d5e8;
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: end;
}

.site-footer nav a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  border-radius: 8px;
  color: #dce7f7;
  padding: 0 10px;
}

.site-footer nav a:hover {
  background: rgba(255, 255, 255, 0.12);
}

@media (max-width: 900px) {
  .nav-toggle {
    display: inline-grid;
    place-items: center;
  }

  .nav-links {
    position: absolute;
    left: 16px;
    right: 16px;
    top: 72px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--surface);
    box-shadow: var(--shadow);
    padding: 10px;
  }

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

  .hero-grid,
  .two-column,
  .download-layout,
  .footer-grid {
    grid-template-columns: 1fr;
  }

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

  .site-footer nav {
    justify-content: start;
  }
}

@media (max-width: 620px) {
  .shell {
    width: min(100% - 24px, var(--shell));
  }

  .hero {
    padding-top: 42px;
  }

  .hero-actions,
  .button {
    width: 100%;
  }

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

  .visual-body {
    grid-template-columns: 1fr;
  }

  .visual-sidebar {
    display: none;
  }

  .visual-panel {
    padding: 18px;
  }

  .section {
    padding: 60px 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}