.guide-menu {
  margin: 0 0 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid #cbd5e1;
}

.guide-menu ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.guide-menu a,
.chapter-nav-link,
.chapter-nav-top {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.5rem 0.8rem;
  border: 1px solid #cbd5e1;
  border-radius: 6px;
  color: #1e40af;
  background: #fff;
  line-height: 1.5;
  text-decoration: none;
}

.guide-menu a[aria-current="page"] {
  border-color: #1e40af;
  background: #eff6ff;
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

.guide-menu a:hover,
.chapter-nav-link:hover,
.chapter-nav-top:hover {
  color: #1e3a8a;
  background: #eff6ff;
  text-decoration: underline;
}

.guide-page a:focus-visible,
.guide-page summary:focus-visible {
  outline: 3px solid #1e40af;
  outline-offset: 3px;
}

.chapter-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  margin-top: 3rem;
  padding-top: 1.25rem;
  border-top: 2px solid #e2e8f0;
}

.chapter-nav-top {
  margin-left: auto;
}

.toc-box {
  margin: 1.5rem 0 2rem;
  padding: 1rem 1.25rem;
  border: 1px solid #e2e8f0;
  border-left: 5px solid #1e40af;
  border-radius: 8px;
  background: #f8fafc;
}

.toc-box summary {
  min-height: 44px;
  padding: 0.5rem 0;
  color: #1e3a8a;
  font-weight: 700;
  cursor: pointer;
}

.toc-box ul {
  margin: 0.5rem 0 0;
  padding-left: 1.25rem;
}

.toc-box li {
  margin: 0.4rem 0;
}

.toc-box a {
  color: #1e40af;
  text-underline-offset: 0.15em;
}

.toc-box ul ul {
  font-size: 0.95em;
}

.guide-page [id] {
  scroll-margin-top: 1rem;
}

@media (max-width: 42rem) {
  .guide-menu li {
    flex: 1 1 9rem;
  }

  .guide-menu a {
    width: 100%;
  }

  .chapter-nav-link {
    flex: 1 1 100%;
  }

  .chapter-nav-top {
    margin-left: 0;
  }
}