/* ============================================================
   Reading Focus — notes-only fullscreen overlay
   ============================================================ */

.reading-focus {
  position: fixed;
  inset: 0;
  z-index: 10050;
  display: flex;
  flex-direction: column;
  background: var(--color-bg);
  animation: readingFocusIn 0.28s var(--ease-out);
}

.reading-focus:fullscreen {
  background: var(--color-bg);
}

@keyframes readingFocusIn {
  from {
    opacity: 0;
    transform: scale(0.985);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

body.reading-focus-active {
  overflow: hidden;
}

/* Minimal exit control — unobtrusive */
.reading-focus__exit {
  position: fixed;
  top: 16px;
  right: 16px;
  z-index: 2;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border: 1px solid color-mix(in srgb, var(--color-border) 70%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--color-bg-elevated) 88%, transparent);
  backdrop-filter: blur(8px);
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  opacity: 0.45;
  transition: opacity 0.2s, background 0.2s, color 0.2s, box-shadow 0.2s;
  box-shadow: 0 2px 12px color-mix(in srgb, var(--color-text) 8%, transparent);
}

.reading-focus:hover .reading-focus__exit,
.reading-focus__exit:hover,
.reading-focus__exit:focus-visible {
  opacity: 1;
  color: var(--color-text-primary);
  background: var(--color-bg-elevated);
}

.reading-focus__hint {
  position: fixed;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  padding: 4px 12px;
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text-tertiary);
  background: color-mix(in srgb, var(--color-bg-elevated) 80%, transparent);
  border-radius: 999px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
}

.reading-focus:hover .reading-focus__hint {
  opacity: 0.7;
}

/* Layout: index + content */
.reading-focus__layout {
  flex: 1;
  display: flex;
  min-height: 0;
  overflow: hidden;
}

/* Topic index sidebar */
.reading-focus__index {
  width: 280px;
  min-width: 280px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--color-border);
  background: var(--color-bg-elevated);
  overflow: hidden;
}

.reading-focus__index-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 16px 16px 12px;
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}

.reading-focus__index-title {
  margin: 0;
  font-size: 11px;
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-text-secondary);
}

.reading-focus__index-count {
  font-size: 11px;
  font-weight: var(--font-weight-semibold);
  color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 12%, transparent);
  padding: 2px 8px;
  border-radius: 999px;
}

.reading-focus__index-body {
  flex: 1;
  overflow-y: auto;
  padding: 8px 10px 16px;
  -webkit-overflow-scrolling: touch;
}

.reading-focus__index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.reading-focus__index-item--h1 .reading-focus__index-link {
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
}

.reading-focus__index-item--h2 .reading-focus__index-link {
  padding-left: 12px;
  font-weight: var(--font-weight-medium);
}

.reading-focus__index-item--h3 .reading-focus__index-link {
  padding-left: 22px;
  font-size: 12px;
  border-left: 2px solid color-mix(in srgb, var(--color-border) 80%, transparent);
  margin-left: 8px;
}

.reading-focus__index-item--h4 .reading-focus__index-link {
  padding-left: 28px;
  font-size: 11px;
  opacity: 0.9;
}

.reading-focus__index-link {
  display: block;
  width: 100%;
  text-align: left;
  padding: 9px 12px;
  border: none;
  border-radius: var(--radius-sm, 6px);
  background: transparent;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  line-height: 1.4;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  white-space: normal;
  word-break: break-word;
}

.reading-focus__index-link:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}

.reading-focus__index-link.is-active {
  background: color-mix(in srgb, var(--color-accent) 14%, transparent);
  color: var(--color-accent);
  font-weight: var(--font-weight-semibold);
}

.reading-focus__index-empty {
  margin: 12px 8px;
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  font-style: italic;
}

/* Mobile index toggle */
.reading-focus__index-toggle {
  display: none;
  position: fixed;
  top: 16px;
  left: 16px;
  z-index: 2;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border: 1px solid color-mix(in srgb, var(--color-border) 70%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--color-bg-elevated) 88%, transparent);
  backdrop-filter: blur(8px);
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  box-shadow: 0 2px 12px color-mix(in srgb, var(--color-text) 8%, transparent);
}

.reading-focus__scroll {
  flex: 1;
  min-width: 0;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
}

.reading-focus__content {
  min-height: 100%;
  padding: 0;
  max-width: none;
}

.reading-focus__content .bn-document {
  max-width: 820px;
  padding: 48px 40px 80px;
}

.reading-focus__content h1,
.reading-focus__content h2,
.reading-focus__content h3,
.reading-focus__content h4,
.reading-focus__content .md-heading {
  scroll-margin-top: 28px;
}

@media (max-width: 900px) {
  .reading-focus__index-toggle {
    display: inline-flex;
  }

  .reading-focus__index {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 3;
    width: min(280px, 85vw);
    min-width: 0;
    transform: translateX(-100%);
    transition: transform 0.25s var(--ease-out);
    box-shadow: 4px 0 24px color-mix(in srgb, var(--color-text) 12%, transparent);
  }

  .reading-focus__index.is-open {
    transform: translateX(0);
  }

  .reading-focus__content .bn-document {
    padding: 48px 24px 80px;
  }
}

@media (max-width: 640px) {
  .reading-focus__content .bn-document {
    padding: 40px 20px 72px;
  }

  .reading-focus__exit {
    top: 10px;
    right: 10px;
    padding: 7px 12px;
  }

  .reading-focus__exit span {
    display: none;
  }

  .reading-focus__index-toggle {
    top: 10px;
    left: 10px;
  }

  .reading-focus__index-toggle span {
    display: none;
  }
}

/* Trigger button in preview chrome */
.note-editor__reading-focus-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  height: 30px;
  padding: 0 12px;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-elevated);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.note-editor__reading-focus-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 8%, var(--color-bg-elevated));
}

.note-editor__reading-focus-btn svg {
  flex-shrink: 0;
}

.note-editor__preview-chrome-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

@media print {
  .reading-focus__exit,
  .reading-focus__hint,
  .reading-focus__index,
  .reading-focus__index-toggle {
    display: none;
  }
}