/* ML Meanders - Table of Contents */

/* ============================================
   ToC Sidebar (Desktop)
   ============================================ */
.toc {
  font-family: var(--font-sans);
  font-size: var(--font-size-sm);
}

.toc-title {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  margin-top: 0;
  padding-left: var(--space-sm);
}

.toc-list ul {
  list-style: none !important;
  padding: 0;
  margin: 0;
  border-left: 1px solid var(--color-border);
}

.toc-list li {
  list-style: none !important;
  margin: 0;
  padding: 0;
}

.toc-list li::before {
  display: none !important;
}

.toc-list li::marker {
  display: none !important;
  content: none !important;
}

.toc-list a {
  display: block;
  padding: var(--space-sm) var(--space-md);
  color: var(--color-text-muted);
  text-decoration: none;
  line-height: 1.5;
  font-size: var(--font-size-sm);
  transition: color var(--transition-fast), border-color var(--transition-fast);
  border-left: 2px solid transparent;
  margin-left: -1px;
}

.toc-list a.active {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
}

.toc-list a:hover {
  color: var(--color-text);
}

/* Nested levels */
.toc-list .toc-h3 a {
  padding-left: var(--space-lg);
  font-size: var(--font-size-xs);
}

.toc-list .toc-h4 a {
  padding-left: var(--space-xl);
  font-size: var(--font-size-xs);
}


/* ============================================
   Mobile ToC (Collapsible)
   ============================================ */
@media (max-width: 1099px) {
  .toc-mobile {
    display: block;
    margin: var(--space-xl) 0;
    padding: var(--space-md);
    background-color: var(--color-bg-subtle);
    border-radius: var(--radius-md);
  }

  .toc-mobile-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 0;
    border: none;
    background: none;
    font-family: var(--font-sans);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text);
    cursor: pointer;
  }

  .toc-mobile-toggle::after {
    content: '+';
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
    transition: transform var(--transition-fast);
  }

  .toc-mobile.open .toc-mobile-toggle::after {
    content: '−';
  }

  .toc-mobile .toc-list {
    display: none;
    margin-top: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px solid var(--color-border);
  }

  .toc-mobile.open .toc-list {
    display: block;
  }

  .toc-mobile .toc-list a {
    padding: var(--space-sm) 0;
  }
}

/* Hide sidebar ToC on smaller screens */
@media (min-width: 1100px) {
  .toc-mobile {
    display: none;
  }
}

/* ============================================
   Scroll Spy Animations
   ============================================ */
.toc-list a.active {
  font-weight: var(--font-weight-medium);
}

/* ============================================
   Back to Top Button
   ============================================ */
.back-to-top {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast), visibility var(--transition-fast),
              background-color var(--transition-fast), color var(--transition-fast);
  z-index: var(--z-above);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: white;
}

.back-to-top svg {
  width: 20px;
  height: 20px;
}

/* Hide on mobile */
@media (max-width: 768px) {
  .back-to-top {
    bottom: var(--space-md);
    right: var(--space-md);
    width: 40px;
    height: 40px;
  }
}