/* ============================================
   PROMETHEUS AI — Interactive Ebook Reader
   Shared Design System
   ============================================ */

/* === READER THEMES === */
.reader {
  --reader-bg: #0A0A0B;
  --reader-surface: #141416;
  --reader-surface-2: #1C1C1F;
  --reader-border: #2A2A2D;
  --reader-divider: #1F1F22;
  --reader-text: #E8E6E1;
  --reader-text-muted: #8A8A8A;
  --reader-text-faint: #5A5A5A;
  --reader-accent: #E8732A;
  --reader-accent-hover: #F28C45;
  --reader-accent-subtle: rgba(232, 115, 42, 0.10);
  --reader-teal: #2A6B5A;
  --reader-teal-subtle: rgba(42, 107, 90, 0.10);
  --reader-code-bg: #111113;
  --reader-shadow: 0 4px 16px rgba(0,0,0,0.4);

  /* Reading widths */
  --reader-max-w: 760px;
  --reader-side-w: 280px;

  /* Font sizes — adjustable via controls */
  --reader-font-size: 1rem;
  --reader-line-height: 1.75;
}

.reader[data-reader-theme="light"] {
  --reader-bg: #F8F8F7;
  --reader-surface: #FFFFFF;
  --reader-surface-2: #F0F0EE;
  --reader-border: #D8D8D5;
  --reader-divider: #E5E5E3;
  --reader-text: #1A1A1A;
  --reader-text-muted: #5A5A58;
  --reader-text-faint: #9A9A98;
  --reader-accent: #D05F1A;
  --reader-accent-hover: #B8521A;
  --reader-accent-subtle: rgba(208, 95, 26, 0.08);
  --reader-teal: #1E5A4B;
  --reader-teal-subtle: rgba(30, 90, 75, 0.08);
  --reader-code-bg: #F0F0EE;
  --reader-shadow: 0 4px 16px rgba(0,0,0,0.08);
}

.reader[data-reader-theme="sepia"] {
  --reader-bg: #F5EFE0;
  --reader-surface: #FAF6ED;
  --reader-surface-2: #EDE7D8;
  --reader-border: #D5CBBA;
  --reader-divider: #E2D9CA;
  --reader-text: #3D3529;
  --reader-text-muted: #7A7060;
  --reader-text-faint: #A89E90;
  --reader-accent: #C05A1A;
  --reader-accent-hover: #A84E15;
  --reader-accent-subtle: rgba(192, 90, 26, 0.10);
  --reader-teal: #2A5E4E;
  --reader-teal-subtle: rgba(42, 94, 78, 0.10);
  --reader-code-bg: #EDE7D8;
  --reader-shadow: 0 4px 16px rgba(60, 50, 30, 0.08);
}

/* === GLOBAL READER RESET === */
.reader {
  min-height: 100dvh;
  background: var(--reader-bg);
  color: var(--reader-text);
  font-family: 'Satoshi', 'Inter', sans-serif;
  font-size: var(--reader-font-size);
  line-height: var(--reader-line-height);
  transition: background 0.3s ease, color 0.3s ease;
}

/* === TOP BAR === */
.reader-topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6, 1.5rem);
  background: var(--reader-surface);
  border-bottom: 1px solid var(--reader-border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.reader-topbar-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-width: 0;
}

.reader-back {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--reader-text-muted);
  text-decoration: none;
  transition: color 0.18s ease;
  white-space: nowrap;
  flex-shrink: 0;
}
.reader-back:hover { color: var(--reader-accent); }
.reader-back svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.reader-topbar-title {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: 0.9375rem;
  font-weight: 400;
  color: var(--reader-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.reader-topbar-right {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex-shrink: 0;
}

.reader-ctrl-btn {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border-radius: 0.5rem;
  color: var(--reader-text-muted);
  cursor: pointer;
  background: none;
  border: none;
  transition: color 0.18s ease, background 0.18s ease;
  position: relative;
}
.reader-ctrl-btn:hover {
  color: var(--reader-text);
  background: var(--reader-surface-2);
}
.reader-ctrl-btn svg {
  width: 18px;
  height: 18px;
}

/* Font size dropdown */
.reader-fontsize-panel {
  position: absolute;
  top: 44px;
  right: 0;
  width: 180px;
  background: var(--reader-surface);
  border: 1px solid var(--reader-border);
  border-radius: 0.75rem;
  padding: 0.75rem;
  box-shadow: var(--reader-shadow);
  display: none;
  z-index: 110;
}
.reader-fontsize-panel.open { display: block; }

.reader-fontsize-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.reader-fontsize-label {
  font-size: 0.75rem;
  color: var(--reader-text-muted);
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.reader-fontsize-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--reader-text);
  min-width: 2.5rem;
  text-align: center;
}

.reader-fontsize-btn {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 0.375rem;
  border: 1px solid var(--reader-border);
  background: var(--reader-surface-2);
  color: var(--reader-text);
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  transition: border-color 0.18s ease;
}
.reader-fontsize-btn:hover { border-color: var(--reader-accent); }

/* Theme selector dropdown */
.reader-theme-panel {
  position: absolute;
  top: 44px;
  right: 0;
  width: 160px;
  background: var(--reader-surface);
  border: 1px solid var(--reader-border);
  border-radius: 0.75rem;
  padding: 0.5rem;
  box-shadow: var(--reader-shadow);
  display: none;
  z-index: 110;
}
.reader-theme-panel.open { display: block; }

.reader-theme-option {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.625rem;
  border-radius: 0.375rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--reader-text);
  cursor: pointer;
  background: none;
  border: none;
  transition: background 0.18s ease;
}
.reader-theme-option:hover { background: var(--reader-surface-2); }
.reader-theme-option.active { color: var(--reader-accent); }

.reader-theme-swatch {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid var(--reader-border);
  flex-shrink: 0;
}
.reader-theme-swatch[data-swatch="dark"] { background: #0A0A0B; }
.reader-theme-swatch[data-swatch="light"] { background: #F8F8F7; }
.reader-theme-swatch[data-swatch="sepia"] { background: #F5EFE0; }
.reader-theme-option.active .reader-theme-swatch { border-color: var(--reader-accent); }

/* Progress bar */
.reader-progress {
  position: fixed;
  top: 56px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--reader-border);
  z-index: 99;
}
.reader-progress-bar {
  height: 100%;
  background: var(--reader-accent);
  width: 0%;
  transition: width 0.3s ease;
}

/* === LAYOUT === */
.reader-body {
  display: flex;
  margin-top: 58px;
  min-height: calc(100dvh - 58px);
}

/* Sidebar / TOC */
.reader-sidebar {
  width: var(--reader-side-w);
  flex-shrink: 0;
  border-right: 1px solid var(--reader-border);
  background: var(--reader-surface);
  position: fixed;
  top: 58px;
  left: 0;
  bottom: 0;
  overflow-y: auto;
  padding: 1.5rem 0;
  z-index: 50;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.reader-sidebar-header {
  padding: 0 1.25rem 1rem;
  border-bottom: 1px solid var(--reader-divider);
  margin-bottom: 0.75rem;
}

.reader-sidebar-badge {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.625rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--reader-accent);
  display: block;
  margin-bottom: 0.375rem;
}

.reader-sidebar-title {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: 1.125rem;
  line-height: 1.25;
  color: var(--reader-text);
}

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

.reader-toc-item {
  display: block;
}

.reader-toc-link {
  display: flex;
  align-items: baseline;
  gap: 0.625rem;
  padding: 0.5rem 1.25rem;
  font-size: 0.8125rem;
  color: var(--reader-text-muted);
  text-decoration: none;
  transition: color 0.18s ease, background 0.18s ease;
  line-height: 1.4;
  border-left: 2px solid transparent;
}
.reader-toc-link:hover {
  color: var(--reader-text);
  background: var(--reader-surface-2);
}
.reader-toc-link.active {
  color: var(--reader-accent);
  border-left-color: var(--reader-accent);
  background: var(--reader-accent-subtle);
}

.reader-toc-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6875rem;
  color: var(--reader-text-faint);
  min-width: 1.25rem;
  flex-shrink: 0;
}
.reader-toc-link.active .reader-toc-num { color: var(--reader-accent); }

/* Mobile sidebar toggle */
.reader-sidebar-toggle {
  display: none;
}

/* Main content */
.reader-main {
  flex: 1;
  margin-left: var(--reader-side-w);
  padding: 3rem 2rem 6rem;
  max-width: calc(var(--reader-max-w) + 4rem);
}

/* === CHAPTER SECTIONS === */
.reader-chapter {
  display: none;
  animation: readerFadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}
.reader-chapter.active { display: block; }

@keyframes readerFadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Chapter header */
.chapter-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--reader-divider);
}

.chapter-number {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--reader-accent);
  margin-bottom: 0.625rem;
  display: block;
}

.chapter-title {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: clamp(1.5rem, 1.2rem + 1.2vw, 2.25rem);
  line-height: 1.15;
  color: var(--reader-text);
  font-weight: 400;
}

.chapter-subtitle {
  font-size: 1rem;
  color: var(--reader-text-muted);
  margin-top: 0.75rem;
  line-height: 1.6;
  max-width: 600px;
}

/* === READING TYPOGRAPHY === */
.reader-prose h2 {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: clamp(1.25rem, 1.1rem + 0.6vw, 1.5rem);
  font-weight: 400;
  color: var(--reader-text);
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.reader-prose h3 {
  font-family: 'Satoshi', sans-serif;
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--reader-text);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  line-height: 1.3;
}

.reader-prose p {
  margin-bottom: 1.25rem;
  max-width: 72ch;
  color: var(--reader-text);
}

.reader-prose ul,
.reader-prose ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}
.reader-prose li {
  margin-bottom: 0.5rem;
  max-width: 72ch;
}

.reader-prose strong {
  font-weight: 600;
  color: var(--reader-text);
}

.reader-prose em {
  font-style: italic;
  color: var(--reader-text-muted);
}

/* Blockquotes */
.reader-prose blockquote {
  border-left: 3px solid var(--reader-accent);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  background: var(--reader-accent-subtle);
  border-radius: 0 0.5rem 0.5rem 0;
  font-style: italic;
  color: var(--reader-text-muted);
}

/* Code / mono */
.reader-prose code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.875em;
  background: var(--reader-code-bg);
  border: 1px solid var(--reader-border);
  border-radius: 0.25rem;
  padding: 0.1em 0.35em;
}

/* === INTERACTIVE COMPONENTS === */

/* --- Expandable Panel (Pro Tips, Frameworks) --- */
.reader-expand {
  border: 1px solid var(--reader-border);
  border-radius: 0.75rem;
  margin: 1.25rem 0;
  overflow: hidden;
  transition: border-color 0.18s ease;
}
.reader-expand:hover { border-color: var(--reader-accent); }

.reader-expand-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.875rem 1.125rem;
  background: var(--reader-surface);
  border: none;
  cursor: pointer;
  color: var(--reader-text);
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  text-align: left;
  gap: 0.75rem;
  transition: background 0.18s ease;
}
.reader-expand-trigger:hover { background: var(--reader-surface-2); }

.reader-expand-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  color: var(--reader-accent);
  transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}
.reader-expand.open .reader-expand-icon { transform: rotate(180deg); }

.reader-expand-badge {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.625rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--reader-accent);
  background: var(--reader-accent-subtle);
  padding: 0.125rem 0.5rem;
  border-radius: 0.25rem;
  flex-shrink: 0;
}

.reader-expand-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}
.reader-expand.open .reader-expand-body { max-height: 2000px; }

.reader-expand-content {
  padding: 0 1.125rem 1rem;
  font-size: 0.875rem;
  color: var(--reader-text-muted);
  line-height: 1.65;
}
.reader-expand-content p { margin-bottom: 0.625rem; }
.reader-expand-content p:last-child { margin-bottom: 0; }

/* --- Copyable Prompt Block --- */
.reader-prompt {
  position: relative;
  margin: 1.25rem 0;
  background: var(--reader-code-bg);
  border: 1px solid var(--reader-border);
  border-radius: 0.75rem;
  overflow: hidden;
}

.reader-prompt-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.875rem;
  border-bottom: 1px solid var(--reader-border);
  background: var(--reader-surface);
}

.reader-prompt-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.625rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--reader-accent);
}

.reader-copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-family: 'Satoshi', sans-serif;
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--reader-text-muted);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  border-radius: 0.25rem;
  transition: color 0.18s ease, background 0.18s ease;
}
.reader-copy-btn:hover {
  color: var(--reader-text);
  background: var(--reader-surface-2);
}
.reader-copy-btn svg {
  width: 14px;
  height: 14px;
}
.reader-copy-btn.copied {
  color: var(--reader-teal);
}

.reader-prompt-body {
  padding: 1rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--reader-text);
  white-space: pre-wrap;
  word-break: break-word;
}

/* --- Technique Card (numbered techniques) --- */
.reader-technique {
  border: 1px solid var(--reader-border);
  border-radius: 0.75rem;
  margin: 1.5rem 0;
  overflow: hidden;
  background: var(--reader-surface);
}

.reader-technique-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.125rem;
  border-bottom: 1px solid var(--reader-divider);
}

.reader-technique-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--reader-accent);
  background: var(--reader-accent-subtle);
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 0.375rem;
  flex-shrink: 0;
}

.reader-technique-title {
  font-family: 'Satoshi', sans-serif;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--reader-text);
}

.reader-technique-body {
  padding: 1rem 1.125rem;
}

.reader-technique-when {
  font-size: 0.8125rem;
  color: var(--reader-text-muted);
  margin-bottom: 1rem;
  line-height: 1.6;
}

.reader-technique-when strong {
  color: var(--reader-teal);
  font-weight: 600;
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.25rem;
}

/* --- Checklist --- */
.reader-checklist {
  list-style: none;
  padding: 0;
  margin: 1.25rem 0;
}

.reader-checklist li {
  display: flex;
  align-items: flex-start;
  gap: 0.625rem;
  padding: 0.5rem 0;
  font-size: 0.875rem;
  color: var(--reader-text);
  border-bottom: 1px solid var(--reader-divider);
}
.reader-checklist li:last-child { border-bottom: none; }

.reader-check {
  width: 18px;
  height: 18px;
  border: 2px solid var(--reader-border);
  border-radius: 0.25rem;
  flex-shrink: 0;
  margin-top: 0.125rem;
  cursor: pointer;
  transition: all 0.18s ease;
  display: grid;
  place-items: center;
}
.reader-check.checked {
  background: var(--reader-accent);
  border-color: var(--reader-accent);
}
.reader-check.checked svg { opacity: 1; }
.reader-check svg {
  width: 12px;
  height: 12px;
  color: #fff;
  opacity: 0;
  transition: opacity 0.18s ease;
}

/* --- Action Panel (CTA) --- */
.reader-action {
  border: 1px solid var(--reader-accent);
  border-radius: 0.75rem;
  padding: 1.5rem;
  margin: 2rem 0;
  background: var(--reader-accent-subtle);
  text-align: center;
}

.reader-action h3 {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: 1.25rem;
  color: var(--reader-text);
  margin-bottom: 0.5rem;
}

.reader-action p {
  font-size: 0.875rem;
  color: var(--reader-text-muted);
  margin-bottom: 1rem;
  max-width: 480px;
  margin-inline: auto;
}

.reader-action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: 'Satoshi', sans-serif;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.625rem 1.5rem;
  background: var(--reader-accent);
  color: #fff;
  border-radius: 9999px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background 0.18s ease, transform 0.18s ease;
}
.reader-action-btn:hover {
  background: var(--reader-accent-hover);
  transform: translateY(-1px);
}

/* --- Key Concept Card --- */
.reader-concept {
  border-left: 3px solid var(--reader-teal);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  background: var(--reader-teal-subtle);
  border-radius: 0 0.5rem 0.5rem 0;
}

.reader-concept-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.625rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--reader-teal);
  margin-bottom: 0.375rem;
  display: block;
}

.reader-concept p {
  font-size: 0.875rem;
  color: var(--reader-text);
  line-height: 1.65;
  margin: 0;
}

/* --- Problem / Fix Card --- */
.reader-problem-fix {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  margin: 1.25rem 0;
  border-radius: 0.75rem;
  overflow: hidden;
  border: 1px solid var(--reader-border);
}

.reader-problem,
.reader-fix {
  padding: 1rem;
  font-size: 0.8125rem;
  line-height: 1.6;
}

.reader-problem {
  background: rgba(196, 68, 58, 0.06);
  border-right: 1px solid var(--reader-border);
}
.reader-fix {
  background: rgba(42, 107, 90, 0.06);
}

.reader-problem-label,
.reader-fix-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.625rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  display: block;
  margin-bottom: 0.375rem;
}
.reader-problem-label { color: #C4443A; }
.reader-fix-label { color: var(--reader-teal); }

/* === CHAPTER NAV FOOTER === */
.reader-chapter-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--reader-divider);
}

.reader-nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--reader-text-muted);
  text-decoration: none;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 0.5rem;
  border: 1px solid var(--reader-border);
  transition: all 0.18s ease;
}
.reader-nav-btn:hover {
  color: var(--reader-text);
  border-color: var(--reader-accent);
  background: var(--reader-accent-subtle);
}
.reader-nav-btn svg {
  width: 16px;
  height: 16px;
}
.reader-nav-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

/* === CINEMATIC COVER (intro chapter) === */
.reader-cover {
  text-align: center;
  padding: 4rem 0 3rem;
}

.reader-cover-badge {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.625rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--reader-accent);
  background: var(--reader-accent-subtle);
  padding: 0.375rem 0.875rem;
  border-radius: 9999px;
  border: 1px solid rgba(232, 115, 42, 0.15);
  display: inline-block;
  margin-bottom: 1.5rem;
}

.reader-cover h1 {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: clamp(2rem, 1.4rem + 2vw, 3rem);
  line-height: 1.1;
  color: var(--reader-text);
  font-weight: 400;
  margin-bottom: 1rem;
}

.reader-cover-sub {
  font-size: 1.0625rem;
  color: var(--reader-text-muted);
  max-width: 520px;
  margin-inline: auto;
  line-height: 1.6;
  margin-bottom: 2rem;
}

.reader-cover-meta {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
  font-size: 0.75rem;
  color: var(--reader-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-family: 'JetBrains Mono', monospace;
}

.reader-cover-divider {
  width: 60px;
  height: 2px;
  background: var(--reader-accent);
  margin: 2rem auto;
  border-radius: 1px;
}

/* === RESPONSIVE === */
@media (max-width: 900px) {
  .reader-sidebar {
    transform: translateX(-100%);
    z-index: 60;
    width: 280px;
  }
  .reader-sidebar.open {
    transform: translateX(0);
    box-shadow: 4px 0 24px rgba(0,0,0,0.3);
  }
  .reader-main {
    margin-left: 0;
    padding: 2rem 1.25rem 5rem;
  }
  .reader-sidebar-toggle {
    display: grid;
  }
  .reader-topbar-title {
    display: none;
  }
}

@media (max-width: 600px) {
  .reader-main {
    padding: 1.5rem 1rem 4rem;
  }
  .reader-problem-fix {
    grid-template-columns: 1fr;
  }
  .reader-problem {
    border-right: none;
    border-bottom: 1px solid var(--reader-border);
  }
  .reader-cover h1 {
    font-size: 1.75rem;
  }
  .chapter-title {
    font-size: 1.375rem;
  }
}

/* Sidebar overlay for mobile */
.reader-sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 55;
}
.reader-sidebar-overlay.open { display: block; }

/* === PRINT === */
@media print {
  .reader-topbar,
  .reader-sidebar,
  .reader-progress,
  .reader-sidebar-toggle,
  .reader-chapter-nav,
  .reader-ctrl-btn { display: none; }
  .reader-main { margin: 0; padding: 0; max-width: 100%; }
  .reader-chapter { display: block !important; page-break-before: always; }
  .reader { background: white; color: black; }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  .reader-chapter { animation: none; }
  .reader-expand-body { transition: none; }
  .reader-expand-icon { transition: none; }
}