.toc-rail {
  --toc-rail-accent: #197ca8;
  --toc-rail-line: rgba(24, 31, 36, 0.14);
  --toc-rail-muted: rgba(24, 31, 36, 0.62);
  --toc-rail-faint: rgba(24, 31, 36, 0.34);
  --toc-rail-text: #181f24;
  --toc-rail-title: rgba(24, 31, 36, 0.38);
  --toc-rail-width: 184px;
  --toc-rail-top: max(116px, 24vh);
  --toc-rail-right: 2rem;
  --toc-rail-left: auto;
  --toc-rail-z-index: 20;
  --toc-rail-font-family:
    system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --toc-rail-title-size: 0.6875rem;
  --toc-rail-link-size: 0.6875rem;
  --toc-rail-link-weight: 500;
  --toc-rail-link-line-height: 1.3;
  --toc-rail-link-indent: 0.75rem;
  --toc-rail-link-nested-indent: 1.25rem;
  --toc-rail-panel-bottom-gap: clamp(1.5rem, 5vh, 5rem);
  --toc-rail-list-bottom-gap: clamp(1.5rem, 5vh, 180px);
  --toc-rail-list-end-space: clamp(1rem, 4vh, 3.5rem);
  --toc-rail-duration-fast: 150ms;
  --toc-rail-duration-normal: 250ms;
  --toc-rail-fade-duration: 500ms;
  --toc-rail-ease-out: cubic-bezier(0, 0, 0.58, 1);
  --toc-rail-fade-transition: var(--toc-rail-fade-duration) var(--toc-rail-ease-out);
  --toc-rail-base-opacity: 0.72;
  --toc-rail-edge-opacity: 1;
  --toc-rail-edge-offset: 0px;
  --toc-rail-edge-translate: 8px;
  --toc-rail-visibility-delay: 0s;
  --_toc-rail-progress-floor: 0.012;
  --_toc-rail-viewport-height: 100vh;
  --_toc-rail-viewport-height: 100dvh;
  --_toc-rail-panel-height: max(
    0px,
    calc(
      var(--_toc-rail-viewport-height) - var(--toc-rail-top) -
        var(--toc-rail-panel-bottom-gap)
    )
  );
  --_toc-rail-list-height: max(
    0px,
    min(
      var(--_toc-rail-panel-height),
      calc(
        var(--_toc-rail-viewport-height) - var(--toc-rail-top) -
          var(--toc-rail-list-bottom-gap)
      )
    )
  );

  position: fixed;
  top: var(--toc-rail-top);
  right: var(--toc-rail-right);
  left: var(--toc-rail-left);
  z-index: var(--toc-rail-z-index);
  width: var(--toc-rail-width);
  color: var(--toc-rail-text);
  font-family: var(--toc-rail-font-family);
  opacity: calc(var(--toc-rail-base-opacity) * var(--toc-rail-edge-opacity));
  transform: translateY(var(--toc-rail-edge-offset));
  visibility: visible;
  transition:
    opacity var(--toc-rail-fade-transition),
    transform var(--toc-rail-fade-transition),
    visibility 0s linear var(--toc-rail-visibility-delay);
}

.toc-rail[hidden] {
  display: none;
}

.toc-rail.is-initializing {
  opacity: 0;
  visibility: hidden;
  transition: none;
}

.toc-rail:focus-within,
.toc-rail:hover,
.toc-rail.is-scrolling {
  --toc-rail-base-opacity: 1;
}

.toc-rail.is-before-content,
.toc-rail[data-toc-rail-state="hidden-before"] {
  --toc-rail-visibility-delay: var(--toc-rail-fade-duration);

  opacity: 0;
  pointer-events: none;
  transform: translateY(var(--toc-rail-edge-translate));
  visibility: hidden;
}

.toc-rail.is-after-content,
.toc-rail[data-toc-rail-state="hidden-after"] {
  --toc-rail-visibility-delay: var(--toc-rail-fade-duration);

  pointer-events: none;
  visibility: hidden;
}

.toc-rail__panel {
  display: flex;
  max-height: var(--_toc-rail-panel-height);
  flex-direction: column;
  gap: 0.75rem;
  overflow: hidden;
  overflow: clip;
}

.toc-rail__title {
  margin: 0 0 0 0.75rem;
  color: var(--toc-rail-title);
  font-size: var(--toc-rail-title-size);
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1;
  text-transform: uppercase;
}

.toc-rail__wrap {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 0;
  max-height: var(--_toc-rail-list-height);
  overflow: hidden;
}

.toc-rail[data-toc-rail-mode="progress"] .toc-rail__wrap {
  height: var(--_toc-rail-list-height);
}

.toc-rail__progress {
  position: absolute;
  top: 4px;
  bottom: calc(4px + var(--toc-rail-list-end-space));
  left: 0;
  width: 1px;
  background: var(--toc-rail-line);
  pointer-events: none;
}

.toc-rail__progress-fill {
  position: absolute;
  inset: 0;
  width: 100%;
  background: var(--toc-rail-accent);
  opacity: 0.9;
  transform: scaleY(max(var(--toc-rail-progress, 0), var(--_toc-rail-progress-floor)));
  transform-origin: top;
  transition: transform var(--toc-rail-duration-fast) linear;
}

.toc-rail.is-scrolling .toc-rail__progress-fill {
  transition: none;
}

.toc-rail__list {
  display: flex;
  flex: 1 1 auto;
  max-height: var(--_toc-rail-list-height);
  min-height: 0;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0 0 var(--toc-rail-list-end-space);
  overflow: auto;
  list-style: none;
  scrollbar-width: none;
}

.toc-rail__list::-webkit-scrollbar {
  width: 0;
  height: 0;
}

.toc-rail__item {
  min-width: 0;
}

.toc-rail__link {
  display: -webkit-box;
  overflow: hidden;
  padding: 4px 0 4px var(--toc-rail-link-indent);
  border-left: 1px solid transparent;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  color: var(--toc-rail-muted);
  font-size: var(--toc-rail-link-size);
  font-weight: var(--toc-rail-link-weight);
  line-height: var(--toc-rail-link-line-height);
  text-decoration: none;
  word-break: keep-all;
  transition:
    border-color var(--toc-rail-duration-fast) var(--toc-rail-ease-out),
    color var(--toc-rail-duration-fast) var(--toc-rail-ease-out);
}

.toc-rail__item--h3 .toc-rail__link,
.toc-rail__item--h4 .toc-rail__link,
.toc-rail__item--h5 .toc-rail__link,
.toc-rail__item--h6 .toc-rail__link {
  padding-left: var(--toc-rail-link-nested-indent);
  color: var(--toc-rail-faint);
}

.toc-rail__item.is-active .toc-rail__link,
.toc-rail__item[data-toc-rail-active="true"] .toc-rail__link {
  color: var(--toc-rail-accent);
}

.toc-rail__link:hover {
  color: var(--toc-rail-text);
  opacity: 1;
}

.toc-rail__link:focus-visible {
  outline: 2px solid var(--toc-rail-accent);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  .toc-rail,
  .toc-rail__link,
  .toc-rail__progress-fill {
    transition: none;
  }
}

[data-theme='dark'] .toc-rail {
  --toc-rail-accent: #60a5fa;
  --toc-rail-line: rgba(255, 255, 255, 0.12);
  --toc-rail-muted: rgba(255, 255, 255, 0.65);
  --toc-rail-faint: rgba(255, 255, 255, 0.35);
  --toc-rail-text: #e2e8f0;
  --toc-rail-title: rgba(255, 255, 255, 0.4);
}