/* ─── DESIGN TOKENS ─── */
:root {
  --bg-base:        #0e0e11;
  --bg-surface:     #16161c;
  --bg-elevated:    #1e1e28;
  --bg-card:        #1a1a24;
  --bg-card-hover:  #22222f;

  --accent:         #c9a84c;
  --accent-dim:     #a07830;
  --accent-glow:    rgba(201,168,76,0.18);
  --accent-2:       #e07b5a;

  --text-primary:   #f0ece2;
  --text-secondary: #9e9880;
  --text-muted:     #5c5848;
  --text-link:      #c9a84c;

  --border:         rgba(201,168,76,0.12);
  --border-strong:  rgba(201,168,76,0.25);

  --sidebar-w:      0px;
  --radius:         12px;
  --radius-sm:      8px;
  --radius-lg:      16px;

  --shadow-card:    0 4px 24px rgba(0,0,0,0.4);
  --shadow-glow:    0 0 40px rgba(201,168,76,0.08);

  --font-display:   'Cinzel', serif;
  --font-body:      'Inter', sans-serif;
  --font-prose:     'Lora', serif;

  --transition:     0.2s ease;
}

/* ─── RESET & BASE ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.65;
  display: flex;
  min-height: 100vh;
  overflow-x: hidden;
}

img { display: block; max-width: 100%; }
button { cursor: pointer; font-family: inherit; border: none; background: none; }
a { color: var(--text-link); }

/* ─── SIDEBAR ─── */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: 240px; /* Constant drawer width */
  height: 100vh;
  background: var(--bg-surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  z-index: 1000; /* High z-index to slide over content */
  padding: 0 0 1.5rem;
  transform: translateX(-240px); /* Hidden drawer by default */
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 1.5rem 1.25rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.logo-icon {
  width: 36px; height: 36px;
  color: var(--accent);
  flex-shrink: 0;
}

.logo-text {
  font-family: var(--font-display);
  font-size: 1.05rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  font-weight: 600;
}

/* ─── SIDEBAR NAV ─── */
.sidebar-nav {
  flex: 1;
  padding: 1rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 4px;
  overflow-y: auto;
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0.6rem 0.875rem;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: background var(--transition), color var(--transition);
  text-align: left;
  width: 100%;
}

.nav-btn svg {
  width: 18px; height: 18px;
  flex-shrink: 0;
  opacity: 0.7;
  transition: opacity var(--transition);
}

.nav-btn:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
}
.nav-btn:hover svg { opacity: 1; }

.nav-btn.active {
  background: var(--accent-glow);
  color: var(--accent);
  border: 1px solid var(--border-strong);
}
.nav-btn.active svg { opacity: 1; color: var(--accent); }

/* ─── SIDEBAR FOOTER ─── */
/* ─── NLM LIVE BADGE ─── */
.nlm-badge {
  display: flex;
  align-items: center;
  gap: 7px;
  margin: 0 0.75rem 0.5rem;
  padding: 0.4rem 0.875rem;
  background: rgba(52, 211, 153, 0.08);
  border: 1px solid rgba(52, 211, 153, 0.25);
  border-radius: 99px;
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #34d399;
}

.nlm-dot {
  width: 7px; height: 7px;
  background: #34d399;
  border-radius: 50%;
  flex-shrink: 0;
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.7); }
}

/* ─── SIDEBAR SOURCE INFO ─── */
.sidebar-footer {
  padding: 0 1.25rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.source-info { }

.source-label {
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.source-name {
  font-size: 0.72rem;
  color: var(--text-secondary);
  line-height: 1.5;
  padding-left: 8px;
  border-left: 2px solid var(--accent-dim);
  margin-bottom: 3px;
}

.source-count {
  font-size: 0.65rem;
  color: var(--accent-dim);
  margin-top: 6px;
  font-weight: 600;
}

.progress-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.progress-bar {
  height: 4px;
  background: var(--bg-elevated);
  border-radius: 99px;
  overflow: hidden;
  margin-bottom: 6px;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  border-radius: 99px;
  transition: width 0.6s ease;
}

.progress-text {
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* ─── MAIN CONTENT ─── */
.main-content {
  margin-left: 0;
  margin: 0 auto;
  flex: 1;
  min-height: 100vh;
  padding: 5.5rem 2.5rem 4rem;
  max-width: 1200px;
  width: 100%;
}

/* ─── SECTION VISIBILITY ─── */
.section { animation: fadeIn 0.3s ease; }
.section[hidden] { display: none; }

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

/* ─── HERO BANNER ─── */
.hero-banner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  padding: 3rem 3rem 3rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  margin-bottom: 2rem;
  position: relative;
  overflow: hidden;
}

.hero-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 70% 50%, rgba(201,168,76,0.06) 0%, transparent 70%);
  pointer-events: none;
}

.hero-eyebrow {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 3.5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.15;
  color: var(--text-primary);
  margin-bottom: 1rem;
}
.hero-title em {
  font-style: italic;
  color: var(--accent);
}

.hero-sub {
  color: var(--text-secondary);
  font-family: var(--font-prose);
  font-size: 0.95rem;
  margin-bottom: 1.75rem;
  max-width: 480px;
}

.hero-cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn-primary {
  background: var(--accent);
  color: #0e0e11;
  font-weight: 600;
  font-size: 0.875rem;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  letter-spacing: 0.02em;
}
.btn-primary:hover {
  background: #e0ba60;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(201,168,76,0.3);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.875rem;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  transition: all var(--transition);
}
.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ─── HERO IMAGE ─── */
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-img-wrap {
  position: relative;
  width: 280px; height: 280px;
  border-radius: 50%;
  overflow: hidden;
}

.hero-img {
  width: 100%; height: 100%;
  object-fit: cover;
  object-position: top center;
  transition: transform 0.5s ease;
}
.hero-img-wrap:hover .hero-img { transform: scale(1.04); }

.hero-img-glow {
  position: absolute;
  inset: -20px;
  background: radial-gradient(circle, rgba(201,168,76,0.12) 0%, transparent 70%);
  pointer-events: none;
}

/* ─── STATS ROW ─── */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1rem;
  text-align: center;
  transition: border-color var(--transition), background var(--transition);
}
.stat-card:hover {
  border-color: var(--border-strong);
  background: var(--bg-card-hover);
}

.stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

/* ─── SECTION TITLE ─── */
.section-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: 0.05em;
  margin-bottom: 1.25rem;
}

/* ─── CHAPTER GRID ─── */
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.chapter-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}
.chapter-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-card), 0 0 24px var(--accent-glow);
}

.chapter-img-wrap {
  position: relative;
  height: 180px;
  overflow: hidden;
}
.chapter-img {
  width: 100%; height: 100%;
  object-fit: cover;
  object-position: top center;
  transition: transform 0.4s ease;
}
.chapter-card:hover .chapter-img { transform: scale(1.06); }

.chapter-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 40%, rgba(14,14,17,0.85) 100%);
  display: flex;
  align-items: flex-start;
  padding: 12px;
}

.chapter-tag {
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  background: rgba(14,14,17,0.7);
  padding: 3px 8px;
  border-radius: 99px;
  border: 1px solid var(--border-strong);
  backdrop-filter: blur(8px);
}

.chapter-body { padding: 1.25rem; }

.chapter-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: 0.03em;
}

.chapter-desc {
  font-family: var(--font-prose);
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.875rem;
  line-height: 1.6;
}

.chapter-meta {
  display: flex;
  align-items: center;
  gap: 10px;
}

.chapter-badge {
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid var(--border-strong);
  padding: 2px 8px;
  border-radius: 99px;
}

.chapter-badge.nlm-sourced {
  color: #34d399;
  background: rgba(52, 211, 153, 0.08);
  border-color: rgba(52, 211, 153, 0.25);
}

/* ─── NLM SOURCE NOTE ─── */
.nlm-source-note {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 0.6rem 1rem;
  background: rgba(52, 211, 153, 0.05);
  border: 1px solid rgba(52, 211, 153, 0.15);
  border-radius: var(--radius-sm);
  font-size: 0.72rem;
  color: #34d399;
  margin-bottom: 1.5rem;
}

.nlm-source-note svg {
  width: 14px; height: 14px;
  flex-shrink: 0;
}

.nlm-source-note strong {
  color: #6ee7b7;
}

/* ─── NOTEBOOK STATUS CARDS ─── */
.notebooks-status {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.notebook-card-status {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid rgba(52, 211, 153, 0.2);
  border-radius: var(--radius);
}

.nb-status-dot {
  width: 10px; height: 10px;
  background: #34d399;
  border-radius: 50%;
  flex-shrink: 0;
  animation: pulse-dot 2s ease-in-out infinite;
}

.nb-status-title {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.nb-status-meta {
  font-size: 0.68rem;
  color: #34d399;
}

.chapter-time {
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* ─── SECTION HEADER ─── */
.section-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.breadcrumb {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.page-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.page-sub {
  font-family: var(--font-prose);
  color: var(--text-secondary);
  font-size: 0.95rem;
  max-width: 600px;
}

/* ─── CONTENT LAYOUT ─── */
.content-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 2rem;
  align-items: start;
}

.content-main { min-width: 0; }

/* ─── HIGHLIGHT BOX ─── */
.highlight-box {
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.highlight-box h2 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 0.6rem;
  letter-spacing: 0.04em;
}

.highlight-box p {
  font-family: var(--font-prose);
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

.highlight-box em { color: var(--accent); font-style: italic; }

/* ─── TOPIC GRID ─── */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 2rem;
}

.topic-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: border-color var(--transition), background var(--transition);
  position: relative;
}
.topic-card:hover {
  border-color: var(--border-strong);
  background: var(--bg-card-hover);
}

.topic-number {
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  color: var(--accent-dim);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
}

.topic-card h3 {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: 0.03em;
}

.topic-card p {
  font-family: var(--font-prose);
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 0.75rem;
}

.key-points {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.key-points li {
  font-size: 0.78rem;
  color: var(--text-muted);
  padding-left: 14px;
  position: relative;
}

.key-points li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--accent-dim);
}

/* ─── MUSCLE TABS ─── */
.muscle-region-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.tab-btn {
  font-size: 0.8rem;
  font-weight: 500;
  padding: 0.45rem 1.1rem;
  border-radius: 99px;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  background: var(--bg-card);
  transition: all var(--transition);
}
.tab-btn:hover {
  border-color: var(--border-strong);
  color: var(--text-primary);
}
.tab-btn.active {
  background: var(--accent-glow);
  border-color: var(--border-strong);
  color: var(--accent);
}

.muscle-content.hidden { display: none; }

/* ─── NOTEBOOKLM PROMPT BOX ─── */
.notebooklm-prompt-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 2rem;
}

.prompt-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0.875rem 1.25rem;
  background: var(--bg-elevated);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  border-bottom: 1px solid var(--border);
}

.prompt-header svg {
  width: 16px; height: 16px;
}

.prompt-list {
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.prompt-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0.75rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
}
.prompt-item:hover {
  border-color: var(--border-strong);
  background: var(--bg-card-hover);
}

.prompt-icon { font-size: 1rem; flex-shrink: 0; }

.prompt-item span:not(.prompt-icon) {
  flex: 1;
  font-family: var(--font-prose);
  font-style: italic;
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.copy-btn {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 3px 10px;
  border-radius: 99px;
  border: 1px solid var(--border-strong);
  color: var(--accent);
  background: var(--accent-glow);
  transition: all var(--transition);
  flex-shrink: 0;
}
.copy-btn:hover {
  background: var(--accent);
  color: #0e0e11;
}

/* ─── STICKY SIDEBAR IMAGE ─── */
.content-sidebar {
  position: sticky;
  top: 2rem;
}

.sticky-img-wrap {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-card);
}

.side-img {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  object-position: top center;
  transition: transform 0.4s ease;
}
.sticky-img-wrap:hover .side-img { transform: scale(1.03); }

.img-caption {
  padding: 0.75rem 1rem;
  font-size: 0.72rem;
  color: var(--text-muted);
  font-style: italic;
  line-height: 1.5;
}

/* ─── PROPORTIONS RULER ─── */
.proportions-ruler {
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.ruler-title {
  font-family: var(--font-display);
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 1rem;
  text-transform: uppercase;
}

.ruler-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.ruler-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  text-align: center;
}

.ruler-num {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 4px;
}

.ruler-landmark {
  font-size: 0.7rem;
  color: var(--text-muted);
  line-height: 1.4;
}

/* ─── NOTEBOOKLM STEPS ─── */
.nlm-steps {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.nlm-step {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 1.25rem;
  align-items: start;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: border-color var(--transition);
}
.nlm-step:hover { border-color: var(--border-strong); }

.step-badge {
  font-family: var(--font-display);
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid var(--border-strong);
  padding: 4px 8px;
  border-radius: 99px;
  text-align: center;
  align-self: start;
  white-space: nowrap;
}

.step-content h3 {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: 0.03em;
}

.step-content p {
  font-family: var(--font-prose);
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.source-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.source-list li {
  font-size: 0.83rem;
  color: var(--text-secondary);
  padding: 0.5rem 0.75rem;
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.inline-link {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: var(--accent-dim);
}

/* ─── TOAST ─── */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 500;
  padding: 0.6rem 1.25rem;
  border-radius: 99px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease, transform 0.25s ease;
  z-index: 999;
  backdrop-filter: blur(12px);
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ─── SCROLLBAR ─── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--bg-elevated); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ─── BASIC FORMS SECTION ─── */

/* Hero card: image left, text right */
.forms-hero-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 2rem;
}

.forms-hero-img {
  height: 380px;
  overflow: hidden;
}

.forms-hero-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.forms-hero-card:hover .forms-hero-img img { transform: scale(1.04); }

.forms-hero-text {
  padding: 2rem 2rem 2rem 0;
}

.forms-hero-text h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  letter-spacing: 0.03em;
}

.forms-hero-text p {
  font-family: var(--font-prose);
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

/* 3-mass list items */
.three-mass-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.mass-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 0.75rem 1rem;
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.mass-shape {
  font-size: 1.4rem;
  color: var(--accent);
  line-height: 1;
  flex-shrink: 0;
  margin-top: 2px;
}

.mass-item strong {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.mass-item span {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-family: var(--font-prose);
  line-height: 1.5;
}

/* Visual form cards — image on top, text below */
.visual-form-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.visual-form-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
}
.visual-form-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-card), 0 0 24px rgba(201,168,76,0.08);
}

.vfc-img-wrap {
  height: 220px;
  overflow: hidden;
  flex-shrink: 0;
  position: relative;
}
.vfc-img-wrap::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 60px;
  background: linear-gradient(transparent, var(--bg-card));
}

.vfc-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform 0.5s ease;
}
.visual-form-card:hover .vfc-img { transform: scale(1.06); }

.vfc-body {
  padding: 1.25rem;
  flex: 1;
}

.vfc-body h3 {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: 0.03em;
}

.vfc-body p {
  font-family: var(--font-prose);
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 0.75rem;
}

/* ─── GENERALIZED VISUAL GRID & CARDS ─── */
.visual-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.visual-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
  height: 100%;
}
.visual-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-card), 0 0 24px rgba(201,168,76,0.08);
}

.v-img-wrap {
  height: 200px;
  overflow: hidden;
  flex-shrink: 0;
  position: relative;
  background: var(--bg-base);
  border-bottom: 1px solid var(--border);
}
.v-img-wrap::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 60px;
  background: linear-gradient(transparent, var(--bg-card));
  pointer-events: none;
}

.v-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform 0.5s ease;
}
.visual-card:hover .v-img { transform: scale(1.06); }

.v-body {
  padding: 1.25rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.v-body h3 {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: 0.03em;
}

.v-body p {
  font-family: var(--font-prose);
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 0.75rem;
}

/* Clickable Images Indicator */
.visual-card .v-img-wrap, 
.visual-form-card .vfc-img-wrap, 
.side-img, 
.chapter-img, 
.forms-hero-img img, 
.hero-img {
  cursor: zoom-in;
}

/* ─── LIGHTBOX MODAL ─── */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(10, 10, 14, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  padding: 2rem;
}

.lightbox.show {
  opacity: 1;
  pointer-events: auto;
}

.lightbox-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  font-size: 2.5rem;
  color: var(--text-secondary);
  transition: color var(--transition), transform var(--transition);
  z-index: 1010;
  line-height: 1;
  cursor: pointer;
}
.lightbox-close:hover {
  color: var(--accent);
  transform: rotate(90deg);
}

.lightbox-content {
  position: relative;
  max-width: 90%;
  max-height: 90%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  transform: scale(0.95);
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
  pointer-events: none;
}

.lightbox.show .lightbox-content {
  transform: scale(1);
  pointer-events: auto;
}

.lightbox-img-wrap {
  position: relative;
  max-height: 70vh;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border-strong);
  box-shadow: 0 20px 50px rgba(0,0,0,0.5);
  background: var(--bg-base);
  transition: max-height 0.4s ease;
}

.lightbox-img-wrap.zoomed-parent {
  max-height: none !important;
  overflow: visible !important;
  width: auto;
}

.lightbox-img {
  max-height: 70vh;
  max-width: 100%;
  object-fit: contain;
  cursor: zoom-in;
  transition: max-width 0.4s cubic-bezier(0.4, 0, 0.2, 1),
              max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.4s cubic-bezier(0.4, 0, 0.2, 1),
              box-shadow 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  transform-origin: center center;
  will-change: max-width, max-height, transform;
}

.lightbox-img.zoomed {
  max-width: 180%;
  max-height: 180vh;
  transform: scale(1.05);
  cursor: zoom-out;
}

/* Bypass flex centering scroll clipping bug when zoomed */
.lightbox.zoomed-modal {
  align-items: flex-start !important;
  justify-content: flex-start !important;
  overflow: auto !important;
}

.lightbox.zoomed-modal .lightbox-content {
  max-width: none;
  max-height: none;
  align-items: flex-start !important;
  margin: 4vh auto;
  pointer-events: auto;
}

.lightbox-caption {
  text-align: center;
  max-width: 600px;
  background: rgba(22, 22, 28, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-strong);
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  color: var(--text-primary);
  box-shadow: var(--shadow-card);
}

.lightbox-title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 0.5rem;
  letter-spacing: 0.05em;
}

.lightbox-desc {
  font-family: var(--font-prose);
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Prevent page scrolling when lightbox is open */
body.lightbox-open {
  overflow: hidden;
}

/* ─── FLOATING CIRCULAR CONTROLS ─── */
.mobile-controls {
  display: flex;
  position: fixed;
  top: 1.5rem;
  left: 1.5rem;
  right: 1.5rem;
  pointer-events: none; /* Click through empty space to underlying page */
  z-index: 990; /* High z-index but below lightbox and sidebar */
  justify-content: space-between;
}

.mobile-control-btn {
  pointer-events: auto; /* Enable click handling on buttons */
  background: rgba(22, 22, 28, 0.7);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-strong);
  color: var(--text-secondary);
  width: 42px; height: 42px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(0,0,0,0.35);
  transition: color var(--transition), background var(--transition), transform var(--transition);
}
.mobile-control-btn:hover, .mobile-control-btn:active {
  color: var(--accent);
  background: var(--bg-elevated);
  transform: scale(1.05);
}
.mobile-control-btn svg {
  width: 18px; height: 18px;
}

/* Breadcrumb back button */
.btn-breadcrumb-back {
  background: none;
  border: none;
  padding: 0;
  color: var(--accent);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color var(--transition);
  display: inline-flex;
  align-items: center;
}
.btn-breadcrumb-back:hover {
  color: var(--text-primary);
}
.breadcrumb-sep {
  margin: 0 8px;
  color: var(--text-muted);
}

/* Adjust sidebar active state on mobile */
.sidebar.mobile-active {
  transform: translateX(0) !important;
  box-shadow: 10px 0 40px rgba(0,0,0,0.8);
  transition: transform 0.3s ease;
}

/* ─── RESPONSIVE ─── */
@media (max-width: 1024px) {
  .content-layout { grid-template-columns: 1fr; }
  .content-sidebar { position: static; }
  .chapter-grid { grid-template-columns: 1fr; }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .hero-banner { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
  .visual-form-grid, .visual-grid { grid-template-columns: repeat(2, 1fr); }
  .forms-hero-card { grid-template-columns: 1fr; }
  .forms-hero-img { height: 260px; }
  .forms-hero-text { padding: 1.5rem; }
}

@media (max-width: 768px) {
  :root { --sidebar-w: 0px; }
  .sidebar {
    transform: translateX(-240px);
    transition: transform 0.3s ease;
  }
  .main-content { margin-left: 0; padding: 1.5rem; margin-top: 0; padding-top: 4.5rem; }
  .mobile-controls { display: flex; }
  .topic-grid { grid-template-columns: 1fr; }
  .ruler-grid { grid-template-columns: repeat(2, 1fr); }
  .nlm-step { grid-template-columns: 1fr; }
  .visual-form-grid, .visual-grid { grid-template-columns: 1fr; }
  .notebooks-status { grid-template-columns: 1fr; }
}

/* ─── HIDE NOTEBOOKLM ELEMENTS ─── */
.nlm-badge,
.nlm-source-note,
.notebooklm-prompt-box,
#nav-notebooklm,
#section-notebooklm,
.sidebar-footer .source-info,
.sidebar-logo .logo-subtitle {
  display: none !important;
}

/* ─── FLOATING DESKTOP HOME BUTTON ─── */
.studio-home-floating-btn {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
  z-index: 999;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0.6rem 1.2rem;
  font-family: var(--font-display), serif;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  text-decoration: none;
  background: rgba(22, 22, 28, 0.75);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-strong);
  border-radius: 99px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  transition: all var(--transition);
  pointer-events: auto;
}
.studio-home-floating-btn:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.5);
}

@media (max-width: 768px) {
  .studio-home-floating-btn {
    display: none !important;
  }
}

/* ─── SIDEBAR BACK BUTTON HOVER ─── */
.sidebar-back-btn:hover {
  background: var(--accent-glow) !important;
  color: var(--text-primary) !important;
  border-color: var(--accent) !important;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(201, 168, 76, 0.15);
}

/* ─── CHAPTER PREV/NEXT NAVIGATION ─── */
.chapter-nav-row {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 3.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}

.btn-nav-next, .btn-nav-prev {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  text-align: left;
  background: rgba(22, 22, 28, 0.45);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.5rem;
  transition: all var(--transition);
  min-width: 240px;
  max-width: 100%;
  flex: 1;
}

.btn-nav-next {
  align-items: flex-end;
  text-align: right;
}

.btn-nav-next:hover, .btn-nav-prev:hover {
  background: rgba(201, 168, 76, 0.05);
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.nav-label {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 4px;
}

.nav-title {
  font-family: var(--font-display), serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: color var(--transition);
}

.btn-nav-next:hover .nav-title, .btn-nav-prev:hover .nav-title {
  color: var(--accent);
}