/* wenxin-outline.css - 文章大纲（TOC）样式：层级缩进、滚动高亮 */
/* ── Article Outline Sidebar ─────────────────────────────────────────────
 * Right-side TOC on post pages, mirroring the left sidebar's
 * absolute-positioning pattern. Same calc() formula flipped to right.
 * Hidden on tablet/mobile — mobile overlay handles those.
 * ─────────────────────────────────────────────────────────────────────── */

.outline-sidebar {
  position: fixed;
  top: var(--space-32);
  right: clamp(4px, 1vw, 12px);
  width: clamp(200px, 16vw, 260px);
  height: calc(100vh - var(--space-32) * 2);
  max-height: calc(100vh - var(--space-32) * 2);
  overflow-y: auto;
  font-family: var(--font-ui);
  font-size: var(--text-xs);
  opacity: 0;
  transition: opacity var(--duration-fast);
  padding-block: var(--space-2);
  padding-left: var(--space-12);
  z-index: 40;
}

.outline-sidebar:hover {
  opacity: 1;
}

.outline-heading {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wider);
  color: var(--color-text-muted);
  margin-bottom: var(--space-5);
}

.outline-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.outline-item {
  line-height: var(--leading-snug);
}

.outline-item a {
  display: block;
  text-decoration: none;
  color: var(--color-text-secondary);
  padding: 3px 0;
  font-size: var(--text-xs);
  transition: color var(--duration-fast);
}

/* Indentation mirrors heading level depth */
.outline-item.outline-h1 a,
.outline-item.outline-h2 a { padding-left: var(--space-3); }
.outline-item.outline-h3 a { padding-left: var(--space-6); }
.outline-item.outline-h4 a { padding-left: var(--space-8); }
.outline-item.outline-h5 a { padding-left: var(--space-10); }
.outline-item.outline-h6 a { padding-left: var(--space-12); }

.outline-item a:hover {
  color: var(--color-text-primary);
}

/* active 规则后置：同特异性下覆盖 hover，高亮项悬浮时保持强调色 */
.outline-item.active a {
  color: var(--color-accent);
}

.outline-item.outline-empty {
  padding: var(--space-2) var(--space-3);
  color: var(--color-text-muted);
  font-style: italic;
}

/* Scrollbar: hidden — content still scrollable, but no visible bar */
.outline-sidebar { scrollbar-width: none; -ms-overflow-style: none; }
.outline-sidebar::-webkit-scrollbar { display: none; width: 0; }

/* ── Back to Top ──────────────────────────────────────────────────────── */

.back-to-top {
  position: fixed;
  bottom: var(--space-8);
  right: var(--space-6);
  z-index: 90;
  width: 40px;
  height: 40px;
  border: 1px solid var(--color-border-subtle);
  border-radius: 50%;
  background: var(--color-bg-pure);
  color: var(--color-text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity var(--duration-base) var(--ease-out),
    transform var(--duration-base) var(--ease-out),
    color var(--duration-fast),
    border-color var(--duration-fast);
  pointer-events: none;
}

.back-to-top.is-visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

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

/* ── Mobile Floating Toggle Buttons ─────────────────────────────────────
 * Hidden on desktop (>768px), shown on post pages mobile.
 * ─────────────────────────────────────────────────────────────────────── */

.mobile-nav-btn,
.mobile-outline-btn {
  display: none;
  position: fixed;
  z-index: 80;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-bg-pure);
  border: 1px solid var(--color-border-subtle);
  color: var(--color-text-secondary);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
  transition: color var(--duration-fast),
    border-color var(--duration-fast);
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  -webkit-user-select: none;
}

.mobile-nav-btn {
  bottom: var(--space-8);
  left: var(--space-6);
}

.mobile-outline-btn {
  bottom: var(--space-8);
  right: var(--space-6);
}

.mobile-nav-btn:active,
.mobile-outline-btn:active {
  color: var(--color-accent);
  border-color: var(--color-accent);
  transform: scale(0.92);
}

@media (hover: hover) and (pointer: fine) {
  .mobile-nav-btn:hover,
  .mobile-outline-btn:hover {
    color: var(--color-accent);
    border-color: var(--color-accent);
  }
}

/* ── Mobile Overlay Backdrop ──────────────────────────────────────────── */

.mobile-overlay-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.35);
  z-index: 84;
  opacity: 0;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.mobile-overlay-backdrop.is-visible {
  display: block;
  opacity: 1;
}

/* ── Mobile Overlay Panels ────────────────────────────────────────────── */

.mobile-nav-overlay,
.mobile-outline-overlay {
  display: none;
  position: fixed;
  top: 0;
  bottom: 0;
  z-index: 85;
  width: 280px;
  max-width: 82vw;
  background: var(--color-bg-pure);
  overflow-y: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  padding: var(--space-10) var(--space-8) var(--space-8);
  transition: transform var(--duration-base) var(--ease-out);
  box-shadow: 0 0 32px rgba(0, 0, 0, 0.12);
}

.mobile-nav-overlay::-webkit-scrollbar,
.mobile-outline-overlay::-webkit-scrollbar { display: none; width: 0; }

.mobile-nav-overlay {
  left: 0;
  transform: translateX(-100%);
}

.mobile-outline-overlay {
  right: 0;
  transform: translateX(100%);
}

.mobile-nav-overlay.is-open {
  transform: translateX(0);
}

.mobile-outline-overlay.is-open {
  transform: translateX(0);
}

/* Overlay content: replicate sidebar brand+navigation */
.mobile-nav-overlay .overlay-brand {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-text-heading);
  margin-bottom: var(--space-6);
}

.mobile-nav-overlay .overlay-bio {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--leading-normal);
  margin-bottom: var(--space-8);
}

.mobile-nav-overlay .overlay-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.mobile-nav-overlay .overlay-nav a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-ui);
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  text-decoration: none;
  border-radius: 4px;
  transition: color var(--duration-fast),
    background-color var(--duration-fast);
}

.mobile-nav-overlay .overlay-nav a.active,
.mobile-nav-overlay .overlay-nav a:hover {
  color: var(--color-text-heading);
  background-color: var(--color-bg-subtle);
}

/* Overlay close button */
.overlay-close {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  width: 36px;
  height: 36px;
  border: none;
  background: none;
  color: var(--color-text-muted);
  font-size: var(--text-lg);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: color var(--duration-fast),
    background-color var(--duration-fast);
}

.overlay-close:hover,
.overlay-close:active {
  color: var(--color-text-primary);
  background-color: var(--color-bg-subtle);
}

/* ── Responsive: hide outline-sidebar, show mobile buttons ────────────── */

@media (max-width: 1024px) {
  .outline-sidebar {
    display: none;
  }

  .mobile-nav-btn,
  .mobile-outline-btn {
    display: flex;
  }
}

/* On non-post pages (index/archive/about), the sidebar already handles
   navigation in the grid — the mobile nav button is unnecessary. */
@media (max-width: 639px) {
  .back-to-top {
    bottom: calc(var(--space-6) + env(safe-area-inset-bottom, 0px));
    right: var(--space-4);
  }

  .mobile-nav-btn {
    bottom: calc(var(--space-6) + env(safe-area-inset-bottom, 0px));
    left: var(--space-4);
  }

  .mobile-outline-btn {
    bottom: calc(var(--space-6) + env(safe-area-inset-bottom, 0px));
    right: var(--space-4);
  }
}

/* ── Print: hide outline and mobile chrome ────────────────────────────── */

@media print {
  .outline-sidebar,
  .mobile-nav-btn,
  .mobile-outline-btn,
  .mobile-overlay-backdrop,
  .mobile-nav-overlay,
  .mobile-outline-overlay,
  .back-to-top {
    display: none !important;
  }
}