/* ========================================
   CHAPTER PAGE SPECIFIC STYLES
======================================== */

/* Chapter Page Body */
.chapter-page {
  background: var(--color-bg-0);
}

/* Chapter Main Container */
.chapter-main {
  min-height: 100vh;
  padding-top: 80px; /* Account for fixed header */
}

/* Chapter Container (Narrower reading width) */
.chapter-container {
  max-width: var(--content-width);
  margin-inline: auto;
  padding-inline: var(--space-md);
}

/* ========================================
   READING CONTROLS
======================================== */

.reading-controls {
  display: flex;
  gap: var(--space-sm);
  align-items: center;
}

.control-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-smooth);
}

.control-btn svg {
  width: 18px;
  height: 18px;
}

.control-btn:hover {
  background: var(--color-bg-1);
  border-color: var(--color-accent-soft);
  color: var(--color-accent);
}

/* ========================================
   TOP NAVIGATION
======================================== */

.chapter-nav-top {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border-subtle);
  background: var(--color-bg-0);
}

.nav-back {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  font-family: var(--font-button);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-smooth);
}

.nav-back::after {
  display: none;
}

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

.nav-back:hover {
  color: var(--color-accent);
}

/* Reading Progress Bar */
.chapter-progress-container {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-bg-1);
  z-index: 1001;
}

.chapter-progress-bar {
  height: 100%;
  background: linear-gradient(
    90deg,
    var(--color-accent-soft),
    var(--color-accent)
  );
  width: 0%;
  transition: width 150ms ease-out;
}

/* ========================================
   CHAPTER HEADER
======================================== */

.chapter-header {
  padding: var(--space-xl) 0 var(--space-lg);
  text-align: center;
  border-bottom: 1px solid var(--color-border-subtle);
}

.chapter-meta {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
  font-size: var(--text-sm);
}

.chapter-number {
  font-family: var(--font-button);
  font-weight: 600;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.chapter-date {
  color: var(--color-text-muted);
}

.chapter-title {
  font-family: var(--font-title);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-text-primary);
  letter-spacing: 0.01em;
  line-height: 1.3;
  max-width: 30ch;
  margin-inline: auto;
}

/* ========================================
   CHAPTER BODY
======================================== */

.chapter-body {
  padding: var(--space-xl) 0;
}

/* Loading State */
.loading-state {
  text-align: center;
  padding: var(--space-xl) 0;
}

.loading-spinner {
  width: 48px;
  height: 48px;
  border: 3px solid var(--color-border-subtle);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  margin: 0 auto var(--space-md);
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-state p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* Error State */
.error-state {
  text-align: center;
  padding: var(--space-xl) 0;
}

.error-state svg {
  width: 64px;
  height: 64px;
  color: var(--color-danger);
  margin: 0 auto var(--space-md);
}

.error-state h2 {
  font-family: var(--font-title);
  font-size: var(--text-xl);
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
}

.error-state p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

/* Chapter Content (Markdown Rendered) */
.chapter-content {
  line-height: 1.8;
}

/* Markdown Typography */
.chapter-content h2 {
  font-family: var(--font-title);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
  letter-spacing: 0.01em;
}

.chapter-content h3 {
  font-family: var(--font-title);
  font-size: var(--text-md);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

.chapter-content p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
  max-width: 100%;
}

.chapter-content strong {
  color: var(--color-text-primary);
  font-weight: 600;
}

.chapter-content em {
  color: var(--color-text-primary);
  font-style: italic;
}

.chapter-content blockquote {
  border-left: 3px solid var(--color-accent-soft);
  padding-left: var(--space-md);
  margin: var(--space-lg) 0;
  color: var(--color-text-muted);
  font-style: italic;
}

.chapter-content hr {
  border: none;
  height: 1px;
  background: var(--color-border-subtle);
  margin: var(--space-xl) 0;
}

.chapter-content ul,
.chapter-content ol {
  margin: var(--space-md) 0;
  padding-left: var(--space-lg);
  color: var(--color-text-secondary);
}

.chapter-content li {
  margin-bottom: var(--space-xs);
}

.chapter-content code {
  font-family: 'Courier New', monospace;
  font-size: 0.9em;
  background: var(--color-bg-1);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
  color: var(--color-accent-soft);
}

.chapter-content pre {
  background: var(--color-bg-1);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin: var(--space-md) 0;
}

.chapter-content pre code {
  background: none;
  padding: 0;
}

/* ========================================
   BOTTOM NAVIGATION
======================================== */

.chapter-nav-bottom {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border-subtle);
}

/* Chapter Pagination */
.chapter-pagination {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.chapter-nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  background: var(--color-bg-1);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--duration-mid) var(--ease-smooth);
}

.chapter-nav-link::after {
  display: none;
}

.chapter-nav-link:hover {
  border-color: var(--color-accent-soft);
  transform: translateY(-2px);
  box-shadow: var(--shadow-elev-1);
}

.chapter-nav-link.prev-chapter {
  justify-content: flex-start;
}

.chapter-nav-link.next-chapter {
  justify-content: flex-end;
  grid-column: 2;
}

.chapter-nav-link svg {
  width: 20px;
  height: 20px;
  color: var(--color-accent);
  flex-shrink: 0;
}

.nav-link-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.nav-link-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.nav-link-title {
  font-family: var(--font-title);
  font-size: var(--text-sm);
  color: var(--color-text-primary);
  font-weight: 500;
}

/* Single navigation item (when only prev or next exists) */
.chapter-pagination:has(.chapter-nav-link:only-child) {
  grid-template-columns: 1fr;
}

/* ========================================
   SHARE SECTION
======================================== */

.chapter-share {
  text-align: center;
  padding: var(--space-lg);
  background: var(--color-bg-1);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-subtle);
}

.chapter-share p {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.share-buttons {
  display: flex;
  justify-content: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.share-btn {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-md);
  font-family: var(--font-button);
  font-size: var(--text-sm);
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-pill);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-smooth);
}

.share-btn svg {
  width: 16px;
  height: 16px;
}

.share-btn:hover {
  background: var(--color-bg-2);
  border-color: var(--color-accent-soft);
  color: var(--color-accent);
}

.share-btn:active {
  transform: scale(0.95);
}

/* ========================================
   FONT SIZE VARIANTS
======================================== */

body.font-small .chapter-content {
  font-size: var(--text-sm);
}

body.font-medium .chapter-content {
  font-size: var(--text-md);
}

body.font-large .chapter-content {
  font-size: var(--text-lg);
}

/* ========================================
   LIGHT THEME (Optional)
======================================== */

body.theme-light {
  --color-bg-0: oklch(98% 0.01 260);
  --color-bg-1: oklch(95% 0.01 260);
  --color-bg-2: oklch(92% 0.01 260);
  --color-text-primary: oklch(20% 0.02 260);
  --color-text-secondary: oklch(40% 0.02 260);
  --color-text-muted: oklch(55% 0.02 260);
  --color-border-subtle: oklch(85% 0.01 260);
  --color-border-strong: oklch(70% 0.02 260);
}

/* ========================================
   RESPONSIVE
======================================== */

@media (max-width: 768px) {
  .chapter-main {
    padding-top: 70px;
  }

  .chapter-header {
    padding: var(--space-lg) 0 var(--space-md);
  }

  .chapter-title {
    font-size: var(--text-lg);
  }

  .chapter-pagination {
    grid-template-columns: 1fr;
  }

  .chapter-nav-link.next-chapter {
    grid-column: 1;
  }

  .reading-controls {
    gap: var(--space-xs);
  }

  .control-btn {
    width: 32px;
    height: 32px;
  }
}

@media (max-width: 600px) {
  .site-title {
    display: none;
  }

  .share-buttons {
    flex-direction: column;
  }

  .share-btn {
    width: 100%;
    justify-content: center;
  }
}