.toc-sidebar {
  position: sticky;
  top: 100px;
  height: calc(100vh - 120px);
  overflow-y: auto;
  padding: 1rem 1.5rem 1rem 0;
  border-right: 1px solid var(--bs-border-color);
  font-size: 0.9rem;
}

.toc-sidebar::-webkit-scrollbar {
  width: 4px;
}

.toc-sidebar::-webkit-scrollbar-thumb {
  background: var(--bs-border-color);
  border-radius: 10px;
}

.toc-list {
  list-style: none;
  padding-left: 0;
  margin-bottom: 0;
}

.toc-list .nav-link {
  color: var(--bs-secondary-color);
  padding: 0.25rem 0;
  transition: color 0.2s ease, border-color 0.2s ease;
  border-left: 2px solid transparent;
  padding-left: 0.75rem;
  margin-left: -1px;
}

.toc-list .nav-link:hover, .toc-list .nav-link.active {
  color: var(--bs-primary);
  border-left-color: var(--bs-primary);
}

.toc-list .toc-nested {
  padding-left: 1rem;
  display: none;
}

/* Show nested list if parent is active or has an active child */

.toc-item.active-parent > .toc-nested {
  display: block;
}

.toc-title {
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: 0.75rem;
  margin-bottom: 1rem;
  color: var(--bs-emphasis-color);
}

/* Smooth scrolling offset for sticky headers */

html {
  scroll-behavior: smooth;
  scroll-padding-top: 8rem;
}

/* Light/Dark mode friendly subtle borders */

[data-bs-theme="dark"] .toc-sidebar {
  border-right-color: rgba(255, 255, 255, 0.1);
}