:root {
  color-scheme: light;
  --bg: #ffffff;
  --text: #111827;
  --muted: #5f6b7a;
  --line: #e6e9ee;
  --soft: #f6f8fb;
  --accent: #1769ff;
  --accent-dark: #0d4fcc;
  --card: #ffffff;
  --shadow: 0 24px 80px rgba(15, 23, 42, 0.08);
}

* {
  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", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.7;
}

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

a:hover {
  color: var(--accent);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px min(6vw, 72px);
  background: rgba(255, 255, 255, 0.86);
  border-bottom: 1px solid rgba(230, 233, 238, 0.9);
  backdrop-filter: saturate(180%) blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: 180px;
}

.brand-logo {
  width: 36px;
  height: 36px;
  display: block;
  object-fit: contain;
  flex: 0 0 auto;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 17px;
  line-height: 1.1;
}

.brand small {
  color: var(--muted);
  font-size: 12px;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
}

.hero {
  max-width: 1120px;
  margin: 0 auto;
  padding: 104px min(6vw, 32px) 88px;
  text-align: center;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

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

h1 {
  margin-bottom: 16px;
  font-size: clamp(48px, 8vw, 92px);
  line-height: 1.02;
  letter-spacing: 0;
}

.hero-subtitle {
  margin-bottom: 20px;
  font-size: clamp(24px, 4vw, 42px);
  line-height: 1.2;
  font-weight: 700;
}

.hero-copy {
  max-width: 720px;
  margin: 0 auto 34px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 22px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-weight: 700;
}

.button-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
}

.button-primary:hover {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
  color: #ffffff;
}

.button-secondary {
  background: #ffffff;
  color: var(--text);
}

.section {
  max-width: 1180px;
  margin: 0 auto;
  padding: 76px min(6vw, 32px);
  border-top: 1px solid var(--line);
}

.section-heading {
  max-width: 680px;
  margin-bottom: 30px;
}

.section h2,
.legal h1 {
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.12;
  letter-spacing: 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.feature-card,
.panel,
.support-box,
.faq details {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
}

.feature-card {
  min-height: 210px;
  padding: 26px;
}

.feature-icon {
  display: inline-flex;
  margin-bottom: 22px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 800;
}

.feature-card h3 {
  margin-bottom: 10px;
  font-size: 21px;
}

.feature-card p,
.panel p,
.legal p,
.support-box p,
.faq p {
  color: var(--muted);
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 26px;
  align-items: start;
}

.panel {
  padding: 28px;
}

.legal {
  width: min(860px, calc(100% - 40px));
  margin: 0 auto;
  padding: 76px 0;
}

.legal h1 {
  margin-bottom: 10px;
}

.legal h2 {
  margin: 44px 0 12px;
  font-size: 25px;
  line-height: 1.3;
}

.updated {
  margin-bottom: 34px;
}

.support-box {
  margin: 20px 0;
  padding: 24px;
}

.support-box h2 {
  margin-top: 0;
}

.faq {
  margin-top: 38px;
}

.faq details {
  margin: 14px 0;
  padding: 18px 20px;
}

.faq summary {
  cursor: pointer;
  font-weight: 700;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 34px min(6vw, 72px);
  border-top: 1px solid var(--line);
  background: var(--soft);
  color: var(--muted);
  font-size: 14px;
}

.site-footer strong {
  color: var(--text);
}

.site-footer p {
  margin: 6px 0 0;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 14px;
}

@media (max-width: 860px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding: 16px 20px;
  }

  .nav {
    justify-content: flex-start;
  }

  .hero {
    padding-top: 72px;
  }

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

  .site-footer {
    flex-direction: column;
  }

  .footer-links {
    justify-content: flex-start;
  }
}

@media (max-width: 520px) {
  body {
    font-size: 15px;
  }

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

  .feature-card {
    min-height: 0;
  }
}