:root {
  color-scheme: light;
  --page-bg: #ffffff;
  --surface: #f7f8fb;
  --surface-blue: #eef4ff;
  --text: #0f172a;
  --text-soft: #526072;
  --text-muted: #6b7280;
  --border: #dbe3ef;
  --primary: #202124;
  --primary-hover: #0f172a;
  --accent: #2563eb;
  --accent-soft: #dbeafe;
  --success: #0f766e;
  --warning-bg: #fff8e7;
  --warning-border: #e8c979;
  --max-width: 1120px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    sans-serif;
  background: var(--page-bg);
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  padding: 10px 14px;
  color: #ffffff;
  background: var(--primary);
  border-radius: 6px;
  transform: translateY(-160%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid rgba(219, 227, 239, 0.8);
  backdrop-filter: blur(14px);
}

.header-inner {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 28px;
  width: min(var(--max-width), calc(100% - 48px));
  min-height: 72px;
  margin: 0 auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 22px;
  font-weight: 800;
  text-decoration: none;
}

.brand img {
  width: 34px;
  height: 34px;
  object-fit: contain;
}

.site-nav {
  display: flex;
  justify-content: center;
  gap: 24px;
}

.site-nav a,
.footer-links a,
.breadcrumb a,
.related-links a {
  color: var(--text-soft);
  font-weight: 600;
  text-decoration: none;
}

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

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 999px;
  transition:
    background-color 180ms ease,
    border-color 180ms ease,
    color 180ms ease;
}

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

.button-primary:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
}

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

.button-secondary:hover {
  color: var(--accent);
  border-color: #a8bce2;
}

a:focus-visible,
summary:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.36);
  outline-offset: 3px;
}

.hero {
  padding: 30px 24px 88px;
  background:
    radial-gradient(circle at 70% 0%, rgba(99, 102, 241, 0.22), transparent 34%),
    radial-gradient(circle at 28% 30%, rgba(207, 242, 245, 0.86), transparent 36%),
    linear-gradient(180deg, #eff6ff 0%, #ffffff 100%);
}

.hero-inner {
  width: min(var(--max-width), 100%);
  margin: 0 auto;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 54px;
  color: var(--text-muted);
  font-size: 14px;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(420px, 1.08fr);
  align-items: center;
  gap: 56px;
}

.eyebrow {
  display: inline-flex;
  margin: 0 0 18px;
  padding: 7px 12px;
  color: #1d4ed8;
  font-size: 13px;
  font-weight: 800;
  background: rgba(219, 234, 254, 0.86);
  border: 1px solid #bfdbfe;
  border-radius: 999px;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: clamp(38px, 5.2vw, 62px);
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.hero-summary {
  max-width: 680px;
  margin: 24px 0 0;
  color: var(--text-soft);
  font-size: 18px;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.hero-proof {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  margin: 28px 0 0;
  padding: 0;
  color: var(--text-soft);
  font-size: 14px;
  list-style: none;
}

.hero-proof li::before {
  margin-right: 7px;
  color: var(--success);
  content: "✓";
}

.product-shot {
  overflow: hidden;
  margin: 0;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 28px 80px rgba(30, 64, 175, 0.16);
}

.product-shot img {
  display: block;
  width: 100%;
  height: auto;
}

.product-shot figcaption {
  padding: 12px 16px;
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.6;
  border-top: 1px solid var(--border);
}

.definition-card {
  padding: 34px;
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 28px 80px rgba(30, 64, 175, 0.14);
}

.definition-card h2 {
  margin: 0;
  font-size: 24px;
  line-height: 1.4;
}

.definition-card p {
  margin: 16px 0 0;
  color: var(--text-soft);
  line-height: 1.8;
}

.definition-list,
.source-list {
  display: grid;
  gap: 12px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.definition-list li,
.source-list li {
  padding: 14px 16px;
  color: var(--text-soft);
  line-height: 1.7;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.source-list a {
  color: var(--accent);
  font-weight: 700;
}

.provenance {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  width: min(var(--max-width), calc(100% - 48px));
  margin: 28px auto 0;
  padding: 16px 20px;
  color: var(--text-soft);
  font-size: 13px;
  line-height: 1.7;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 10px;
}

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

.section {
  padding: 88px 24px;
}

.section-alt {
  background: var(--surface);
}

.section-inner {
  width: min(var(--max-width), 100%);
  margin: 0 auto;
}

.section-head {
  max-width: 760px;
  margin-bottom: 38px;
}

.section-head h2,
.boundary h2,
.final-cta h2 {
  margin: 0;
  font-size: clamp(28px, 3.5vw, 40px);
  line-height: 1.28;
}

.section-head p,
.boundary p,
.final-cta p {
  margin: 16px 0 0;
  color: var(--text-soft);
  font-size: 16px;
  line-height: 1.8;
}

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

.card {
  min-height: 210px;
  padding: 28px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 10px;
}

.card-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  color: #1d4ed8;
  font-size: 13px;
  font-weight: 800;
  background: var(--accent-soft);
  border-radius: 50%;
}

.card h3 {
  margin: 22px 0 0;
  font-size: 20px;
  line-height: 1.4;
}

.card p {
  margin: 12px 0 0;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1.75;
}

.workflow {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: workflow;
}

.workflow li {
  position: relative;
  min-height: 180px;
  padding: 28px 24px;
  background: var(--surface-blue);
  border: 1px solid #d8e5fb;
  border-radius: 10px;
  counter-increment: workflow;
}

.workflow li::before {
  display: block;
  margin-bottom: 18px;
  color: var(--accent);
  font-size: 14px;
  font-weight: 800;
  content: "0" counter(workflow);
}

.workflow strong {
  display: block;
  font-size: 17px;
  line-height: 1.45;
}

.workflow span {
  display: block;
  margin-top: 10px;
  color: var(--text-soft);
  font-size: 14px;
  line-height: 1.7;
}

.boundary {
  width: min(var(--max-width), calc(100% - 48px));
  margin: 80px auto;
  padding: 36px 40px;
  background: var(--warning-bg);
  border: 1px solid var(--warning-border);
  border-radius: 12px;
}

.boundary h2 {
  font-size: 25px;
}

.faq-list {
  display: grid;
  gap: 14px;
}

.faq-list details {
  padding: 0 24px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 10px;
}

.faq-list summary {
  min-height: 64px;
  padding: 20px 32px 20px 0;
  font-size: 16px;
  font-weight: 800;
  line-height: 1.5;
  cursor: pointer;
}

.faq-list details p {
  margin: 0;
  padding: 0 0 22px;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1.8;
}

.related-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.related-links a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 16px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 999px;
}

.final-cta {
  padding: 88px 24px;
  text-align: center;
  background:
    radial-gradient(circle at 70% 20%, rgba(99, 102, 241, 0.2), transparent 34%),
    linear-gradient(180deg, #ffffff 0%, #eaf2ff 100%);
}

.final-cta-inner {
  max-width: 820px;
  margin: 0 auto;
}

.final-cta .button {
  margin-top: 28px;
}

.site-footer {
  padding: 36px 24px;
  color: var(--text-muted);
  background: #f7f8fb;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: end;
  gap: 24px;
  width: min(var(--max-width), 100%);
  margin: 0 auto;
}

.footer-brand {
  margin: 0;
  color: var(--text);
  font-weight: 800;
}

.footer-meta {
  margin: 10px 0 0;
  font-size: 12px;
  line-height: 1.8;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 18px;
  font-size: 13px;
}

@media (max-width: 900px) {
  .site-nav {
    display: none;
  }

  .header-inner {
    grid-template-columns: 1fr auto;
  }

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

  .product-shot {
    max-width: 760px;
  }

  .definition-card {
    max-width: 760px;
  }

  .card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .workflow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .header-inner {
    width: calc(100% - 32px);
    min-height: 64px;
  }

  .header-inner > .button {
    min-height: 42px;
    padding: 0 15px;
    font-size: 13px;
  }

  .hero {
    padding: 22px 16px 64px;
  }

  .breadcrumb {
    margin-bottom: 38px;
  }

  .hero-grid {
    gap: 38px;
  }

  h1 {
    font-size: 36px;
  }

  .hero-summary {
    font-size: 16px;
  }

  .hero-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .button {
    width: 100%;
  }

  .section {
    padding: 64px 16px;
  }

  .card-grid,
  .workflow {
    grid-template-columns: 1fr;
  }

  .card,
  .workflow li {
    min-height: auto;
  }

  .boundary {
    width: calc(100% - 32px);
    margin: 56px auto;
    padding: 28px 24px;
  }

  .provenance {
    width: calc(100% - 32px);
  }

  .final-cta {
    padding: 64px 16px;
  }

  .footer-inner {
    grid-template-columns: 1fr;
  }

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

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}