.handbook-intro {
  position: relative;
  padding-top: 36px;
  padding-bottom: 36px;
  overflow-x: clip;
}

.handbook-intro::before {
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(var(--color-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
  background-position: center;
  background-size: 56px 56px;
  content: "";
  opacity: 0.7;
  -webkit-mask-image: radial-gradient(ellipse at center, var(--color-text), transparent 72%);
  mask-image: radial-gradient(ellipse at center, var(--color-text), transparent 72%);
}

.handbook-intro__panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.56fr);
  gap: 42px;
  align-items: center;
}

.handbook-intro__copy {
  max-width: 700px;
}

.handbook-intro h1 {
  max-width: 680px;
}

.handbook-intro__lead {
  max-width: 660px;
  margin-top: 18px;
  margin-bottom: 0;
  color: var(--color-muted);
  font-size: 19px;
  line-height: 1.8;
}

.handbook-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 24px;
}

.handbook-route {
  padding: 24px;
}

.handbook-route__title {
  margin-bottom: 16px;
  font-weight: 800;
}

.handbook-route ol {
  display: grid;
  gap: 13px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.handbook-route li {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-muted);
  font-size: 14px;
}

.handbook-route li span {
  display: inline-flex;
  width: 34px;
  height: 34px;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-mint);
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
}

.handbook-content {
  padding-top: 68px;
}

.handbook-layout {
  position: relative;
}

.handbook-layout .toc-tabs {
  top: 12px;
}

.handbook-article {
  max-width: calc(860px + var(--gutter) * 2);
}

.handbook-preface {
  margin-bottom: 44px;
  padding: 26px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  background: var(--color-panel);
  color: var(--color-text);
}

.handbook-preface p:last-child {
  margin-bottom: 0;
}

.handbook-chapter {
  padding-top: 34px;
  padding-bottom: 34px;
  scroll-margin-top: 82px;
}

.handbook-chapter + .handbook-chapter {
  margin-top: 38px;
  border-top: 1px solid var(--color-border);
}

.handbook-chapter h2 {
  margin-top: 0;
}

.chapter-index {
  margin-bottom: 10px;
  color: var(--color-accent-dark);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.handbook-chapter h3 {
  padding-left: 14px;
  border-left: 3px solid var(--color-accent);
}

.handbook-chapter p {
  text-align: justify;
  text-justify: inter-ideograph;
}

.handbook-chapter .table-scroll {
  margin-top: 28px;
  margin-bottom: 30px;
}

.handbook-chapter pre {
  margin-top: 24px;
}

.handbook-summary {
  margin-top: 56px;
}

@media (max-width: 900px) {
  .handbook-intro__panel {
    grid-template-columns: 1fr;
  }

  .handbook-route {
    max-width: 620px;
  }
}

@media (max-width: 768px) {
  .handbook-intro {
    padding-top: 20px;
    padding-bottom: 20px;
  }

  .handbook-intro__lead {
    font-size: 16px;
  }

  .handbook-content {
    padding-top: 48px;
  }

  .handbook-preface {
    padding: 20px;
  }

  .handbook-chapter {
    padding-top: 24px;
    padding-bottom: 24px;
  }

  .handbook-chapter p {
    text-align: left;
  }
}

@media (max-width: 640px) {
  .handbook-intro__panel {
    gap: 28px;
  }

  .handbook-route {
    padding: 20px;
  }

  .handbook-facts .fact-chip {
    flex: 1 1 auto;
    justify-content: center;
  }

  .handbook-chapter + .handbook-chapter {
    margin-top: 20px;
  }
}