:root {
  --ink: #142234;
  --muted: #647084;
  --line: #dce4ee;
  --paper: #f6f8fb;
  --brand: #c5251f;
  --brand-dark: #891b18;
  --blue: #195bb5;
  --blue-dark: #123e7d;
  --green: #23715f;
  --shadow: 0 24px 70px rgba(24, 40, 62, .12);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: #fff;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #fff;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 0 56px;
  background: rgba(255, 255, 255, .92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.site-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.site-brand span {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  color: #fff;
  background: linear-gradient(145deg, var(--brand), var(--brand-dark));
  font-size: 22px;
  font-weight: 900;
}

.site-brand strong {
  font-size: 20px;
  letter-spacing: 0;
  white-space: nowrap;
}

.site-header nav {
  display: flex;
  align-items: center;
  gap: 24px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.site-header nav a:last-child {
  padding: 10px 14px;
  border: 1px solid #b8c9dd;
  border-radius: 8px;
  color: var(--blue-dark);
}

.hero {
  min-height: calc(100vh - 118px);
  display: grid;
  grid-template-columns: minmax(0, .95fr) minmax(520px, 1.05fr);
  gap: 42px;
  align-items: center;
  padding: 56px 56px 42px;
  overflow: hidden;
  background:
    linear-gradient(180deg, #ffffff 0, #f7faff 100%);
}

.hero-copy {
  max-width: 620px;
}

.hero h1 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(52px, 6vw, 92px);
  line-height: .96;
  letter-spacing: 0;
}

.hero h1::first-letter {
  color: var(--brand);
}

.hero-copy p {
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 22px;
  line-height: 1.65;
}

.hero-actions,
.download-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 30px;
}

.primary,
.secondary {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  padding: 0 22px;
  font-weight: 800;
  line-height: 1.2;
}

.primary {
  color: #fff;
  background: var(--brand);
  box-shadow: 0 12px 24px rgba(197, 37, 31, .18);
}

.secondary {
  color: var(--blue-dark);
  background: #fff;
  border: 1px solid #a9bfda;
}

.hero-proof {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
  color: var(--blue-dark);
}

.hero-proof span {
  padding: 8px 10px;
  border-radius: 8px;
  background: #eef5ff;
  border: 1px solid #d3e3f8;
  font-size: 13px;
  font-weight: 800;
}

.hero-visual {
  position: relative;
  min-height: 540px;
}

.book-stack {
  position: relative;
  height: 360px;
}

.book-stack img {
  position: absolute;
  width: 230px;
  max-width: 34%;
  filter: drop-shadow(0 24px 28px rgba(20, 34, 52, .18));
}

.book-stack img:nth-child(1) {
  left: 0;
  top: 64px;
  z-index: 3;
}

.book-stack img:nth-child(2) {
  left: 29%;
  top: 18px;
  z-index: 2;
}

.book-stack img:nth-child(3) {
  right: 0;
  top: 86px;
  z-index: 1;
}

.dashboard-preview {
  position: absolute;
  left: 6%;
  right: 0;
  bottom: 0;
  min-height: 236px;
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 18px;
  padding: 18px;
  border: 1px solid #d7e1ee;
  border-radius: 8px;
  background: rgba(255, 255, 255, .94);
  box-shadow: var(--shadow);
}

.preview-sidebar {
  display: grid;
  gap: 12px;
  padding: 14px 10px;
  border-radius: 8px;
  background: var(--blue-dark);
}

.preview-sidebar span,
.preview-row,
.preview-metrics span,
.preview-grid span {
  display: block;
  border-radius: 6px;
  background: #e9f1fb;
}

.preview-sidebar span {
  height: 18px;
  background: rgba(255, 255, 255, .82);
}

.preview-main {
  display: grid;
  gap: 14px;
}

.preview-row.strong {
  height: 32px;
  width: 42%;
  background: #dce8f8;
}

.preview-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.preview-metrics span {
  height: 60px;
  background: #f7f9fc;
  border: 1px solid var(--line);
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.preview-grid span {
  height: 46px;
  border: 1px solid var(--line);
  background: #fff;
}

.book-section,
.workflow-section,
.download-section {
  padding: 66px 56px;
}

.section-head {
  max-width: 760px;
  margin: 0 auto 30px;
  text-align: center;
}

.section-head h2,
.download-section h2 {
  margin: 0;
  font-size: 34px;
  line-height: 1.25;
  letter-spacing: 0;
}

.section-head p,
.download-section p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.75;
}

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

.book-cards article {
  min-height: 256px;
  display: grid;
  grid-template-columns: 116px minmax(0, 1fr);
  gap: 18px;
  align-items: center;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 14px 36px rgba(24, 40, 62, .06);
}

.book-cards img {
  width: 116px;
  height: auto;
  filter: drop-shadow(0 14px 18px rgba(20, 34, 52, .14));
}

.book-cards span,
.workflow-grid span {
  color: var(--brand);
  font-weight: 900;
  font-size: 13px;
}

.book-cards h3 {
  margin: 8px 0;
  font-size: 22px;
  letter-spacing: 0;
}

.book-cards p,
.workflow-grid p {
  margin: 0;
  color: var(--muted);
  line-height: 1.7;
}

.workflow-section {
  background: var(--paper);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.workflow-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.workflow-grid article {
  min-height: 186px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  display: grid;
  align-content: start;
  gap: 10px;
}

.workflow-grid strong {
  font-size: 20px;
}

.download-section {
  display: grid;
  grid-template-columns: minmax(0, .9fr) minmax(520px, 1.1fr);
  gap: 32px;
  align-items: center;
  background: #fff;
}

.download-section code {
  padding: 2px 5px;
  border-radius: 5px;
  color: var(--blue-dark);
  background: #eef5ff;
}

.download-copy {
  min-width: 0;
}

.domain-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 22px;
}

.domain-grid span {
  display: grid;
  gap: 3px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbff;
}

.domain-grid strong {
  font-size: 13px;
  line-height: 1.35;
  word-break: break-all;
}

.domain-grid em {
  color: var(--muted);
  font-size: 12px;
  font-style: normal;
}

.download-card {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  gap: 16px;
  padding: 16px;
  border: 1px solid #d7e1ee;
  border-radius: 8px;
  background: #fff;
  box-shadow: var(--shadow);
}

.qr-card {
  display: grid;
  align-content: start;
  gap: 10px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbff;
  text-align: center;
}

.qr-card img {
  width: 100%;
  aspect-ratio: 1;
  border-radius: 8px;
  background: #fff;
}

.qr-card span {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.release-card {
  min-width: 0;
}

.release-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: start;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.release-head span {
  display: block;
  color: var(--blue-dark);
  font-size: 12px;
  font-weight: 850;
}

.release-head strong {
  display: block;
  margin-top: 4px;
  font-size: 22px;
  line-height: 1.25;
}

.release-head em {
  flex: 0 0 auto;
  padding: 7px 9px;
  border-radius: 7px;
  color: var(--green);
  background: #eefaf5;
  font-size: 12px;
  font-style: normal;
  font-weight: 850;
}

.release-meta {
  display: grid;
  gap: 8px;
  margin: 14px 0;
}

.release-meta div {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
}

.release-meta dt {
  color: var(--muted);
  font-size: 12px;
}

.release-meta dd {
  margin: 0;
  color: var(--ink);
  font-size: 13px;
  line-height: 1.45;
  word-break: break-all;
}

.install-steps {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin-top: 12px;
}

.install-steps span {
  padding: 8px 9px;
  border: 1px solid var(--line);
  border-radius: 7px;
  color: var(--blue-dark);
  background: #f8fbff;
  font-size: 12px;
  font-weight: 800;
}

footer {
  min-height: 74px;
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 0 56px;
  color: var(--muted);
  border-top: 1px solid var(--line);
  font-size: 13px;
}

footer a {
  color: var(--blue-dark);
}

@media (max-width: 1100px) {
  .hero,
  .download-section {
    grid-template-columns: 1fr;
  }

  .hero-visual {
    min-height: 500px;
  }

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

@media (max-width: 760px) {
  .site-header {
    height: auto;
    min-height: 68px;
    align-items: flex-start;
    padding: 14px 18px;
  }

  .site-brand strong {
    font-size: 16px;
  }

  .site-header nav {
    display: none;
  }

  .hero,
  .book-section,
  .workflow-section,
  .download-section {
    padding: 34px 18px;
  }

  .hero h1 {
    font-size: 48px;
  }

  .hero-copy p {
    font-size: 18px;
  }

  .hero-visual {
    min-height: 430px;
  }

  .book-stack {
    height: 258px;
  }

  .book-stack img {
    width: 160px;
    max-width: 40%;
  }

  .dashboard-preview {
    left: 0;
    grid-template-columns: 48px minmax(0, 1fr);
  }

  .book-cards,
  .workflow-grid,
  .download-card,
  .book-cards article {
    grid-template-columns: 1fr;
  }

  .qr-card {
    max-width: 260px;
  }

  .download-actions,
  .hero-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .domain-grid,
  .install-steps {
    grid-template-columns: 1fr;
  }

  footer {
    flex-wrap: wrap;
    padding: 18px;
  }
}