.dk-sticky-toc {
  --dk-sticky-toc-bg: light-dark(var(--color-purple-100), var(--color-purple-700));
  position: sticky;
  top: var(--dk-sticky-toc-top, 0);
  z-index: var(--z-chrome, 20);
  background: var(--dk-sticky-toc-bg);
  border-bottom: var(--border-width-thin) solid var(--color-border);
}

.dk-sticky-toc-summary {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  padding-top: calc(var(--spacing-md) + env(safe-area-inset-top, 0px));
  padding-left: calc(var(--spacing-lg) + env(safe-area-inset-left, 0px));
  padding-right: calc(var(--spacing-lg) + env(safe-area-inset-right, 0px));
  background: transparent;
  border: none;
  cursor: pointer;
  font-family: var(--typography-mono);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  line-height: var(--font-line-height-base);
  color: var(--color-text);
  text-align: left;
}

.dk-sticky-toc-summary:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: -2px;
}

.dk-sticky-toc-current {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.dk-sticky-toc-current:empty::before {
  content: attr(data-fallback);
  color: var(--color-text-muted);
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
  letter-spacing: var(--font-letter-spacing-wide, 0.03em);
  font-size: var(--font-size-xs);
}

.dk-sticky-toc-chevron {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--typography-mono);
  font-size: var(--font-size-sm);
  line-height: 1;
  color: var(--color-text);
}

.dk-sticky-toc[data-state="expanded"] .dk-sticky-toc-summary .dk-sticky-toc-chevron {
  visibility: hidden;
}

.dk-sticky-toc-panel {
  display: flex;
  flex-direction: column;
  background: var(--dk-sticky-toc-bg);
  max-height: 0;
  visibility: hidden;
  overflow: hidden;
  transition:
    max-height var(--motion-duration-base, 0.25s) var(--motion-easing-default, ease),
    visibility 0s linear var(--motion-duration-base, 0.25s);
}

.dk-sticky-toc[data-state="expanded"] .dk-sticky-toc-panel {
  max-height: 70vh;
  visibility: visible;
  transition:
    max-height var(--motion-duration-base, 0.25s) var(--motion-easing-default, ease),
    visibility 0s linear 0s;
}

@media (prefers-reduced-motion: reduce) {
  .dk-sticky-toc-panel {
    transition: none;
  }
}

.dk-sticky-toc-list {
  list-style: none;
  margin: 0;
  padding: var(--spacing-md) 0;
  overflow-y: auto;
  scrollbar-gutter: stable;
  scrollbar-color: var(--color-border) transparent;
  scrollbar-width: thin;
}

.dk-sticky-toc-item {
  border-left: 2px solid transparent;
  transition: border-color var(--motion-duration-fast, 0.15s) var(--motion-easing-default, ease);
}

.dk-sticky-toc-item-active {
  border-left-color: var(--color-link);
}

.dk-sticky-toc-item-active .dk-sticky-toc-link {
  color: var(--color-text);
}

.dk-sticky-toc-item-level-0 { padding-left: 0; }
.dk-sticky-toc-item-level-1 { padding-left: var(--spacing-lg); }
.dk-sticky-toc-item-level-2 { padding-left: var(--spacing-2xl); }

.dk-sticky-toc-link {
  display: block;
  font-family: var(--typography-mono);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-regular);
  color: var(--color-text-muted);
  text-decoration: none;
  padding: var(--spacing-sm) var(--spacing-lg);
  line-height: var(--font-line-height-base);
  transition: color var(--motion-duration-fast, 0.15s) var(--motion-easing-default, ease);
}

.dk-sticky-toc-link:hover {
  color: var(--color-text);
}

.dk-sticky-toc-link:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: -2px;
}

.dk-sticky-toc-tldr {
  display: none;
  font-family: var(--typography-mono);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-regular);
  line-height: var(--font-line-height-base);
  color: var(--color-text);
  padding: 0 var(--spacing-lg) var(--spacing-sm) calc(var(--spacing-lg) + var(--spacing-md));
}

.dk-sticky-toc-item-active .dk-sticky-toc-tldr {
  display: block;
}

.dk-sticky-toc-dismiss {
  align-self: flex-end;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--color-text);
  font-family: var(--typography-mono);
  font-size: var(--font-size-md);
  line-height: 1;
}

.dk-sticky-toc-dismiss:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: -2px;
}

.dk-sticky-toc-title {
  display: none;
  font-family: var(--typography-mono);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: var(--font-letter-spacing-wide, 0.05em);
  padding: 0 0 var(--spacing-md);
}

.dk-sticky-toc-back {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-family: var(--typography-mono);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: var(--font-letter-spacing-wide, 0.05em);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-bottom: var(--border-width-thin) solid var(--color-border);
  transition: color var(--motion-duration-fast, 0.15s) var(--motion-easing-default, ease);
}

/* Trim the label's box to its cap rectangle (cap height to alphabetic
   baseline). align-items: center then centres the chevron's point on the
   optical middle of the caps instead of the taller line box, which would
   otherwise leave the icon sitting slightly low. */
.dk-sticky-toc-back-label {
  text-box: trim-both cap alphabetic;
}

.dk-sticky-toc-back:hover { color: var(--color-text); }
.dk-sticky-toc-back:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: -2px;
}
/* Vendored DK chevron-left icon (public/icons/), recoloured via mask so it
   tracks the link's currentColor (muted at rest, --color-text on hover). */
.dk-sticky-toc-back::before {
  content: "";
  flex: none;
  width: 1em;
  height: 1em;
  background-color: currentColor;
  -webkit-mask: url("../icons/chevron-left.svg") center / contain no-repeat;
          mask: url("../icons/chevron-left.svg") center / contain no-repeat;
}

/* Responsive layout: at wide viewports, instances marked
   .dk-sticky-toc-responsive switch from a sticky top bar to a fixed
   left rail. Same DOM, same items, same active-tracking.
   Mirror of --breakpoint-wide (in style.css). */
@media (min-width: 1100px) {
  .dk-sticky-toc-responsive {
    position: fixed;
    top: var(--dk-sticky-toc-rail-top, 2rem);
    left: var(--dk-sticky-toc-rail-left, 1rem);
    right: auto;
    max-width: var(--dk-sticky-toc-rail-max-width, 200px);
    background: transparent;
    border-bottom: none;
    z-index: var(--z-sticky, 10);
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-summary {
    display: none;
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-panel {
    max-height: none;
    visibility: visible;
    overflow: visible;
    background: transparent;
    transition: none;
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-list {
    padding: 0;
    overflow: visible;
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-link {
    font-size: var(--font-size-xs);
    padding: 2px 0 2px var(--spacing-md);
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-tldr {
    padding: 2px 0 var(--spacing-sm) var(--spacing-xl);
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-dismiss {
    display: none;
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-title {
    display: block;
  }

  .dk-sticky-toc-responsive .dk-sticky-toc-back {
    padding: 0 0 var(--spacing-md);
    margin-bottom: var(--spacing-md);
  }
}