:root {
  --color-bg: #FAFAF8;
  --color-bg-alt: #F1EFE8;
  --color-surface: #FFFFFF;
  --color-text: #2C2C2A;
  --color-text-muted: #5F5E5A;
  --color-text-soft: #888780;
  --color-border: #D3D1C7;
  --color-border-soft: #E8E6DD;
  --color-accent: #6B4F2D;
  --color-accent-soft: #C9A878;
  --color-active: #534AB7;
  --color-active-bg: #EEEDFE;
  --color-flow: #7F77DD;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'Libre Baskerville', Georgia, serif;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-soft: 0 1px 3px rgba(0,0,0,0.04);
  --transition: 0.2s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1A1A18;
    --color-bg-alt: #232320;
    --color-surface: #2A2A26;
    --color-text: #E8E6DD;
    --color-text-muted: #B4B2A9;
    --color-text-soft: #888780;
    --color-border: #3A3A35;
    --color-border-soft: #2F2F2B;
    --color-accent: #C9A878;
    --color-accent-soft: #8C6A40;
    --color-active: #AFA9EC;
    --color-active-bg: #26215C;
    --color-flow: #AFA9EC;
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.site-header {
  padding: 2.5rem 0 1.5rem;
  border-bottom: 1px solid var(--color-border-soft);
  margin-bottom: 2rem;
}

.site-header h1 {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 0.4rem;
  color: var(--color-text);
}

.subtitle {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  font-style: italic;
}

.intro {
  margin-bottom: 2rem;
  max-width: 800px;
}

.intro p {
  margin-bottom: 0.75rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.intro p:first-child {
  font-size: 1.05rem;
  color: var(--color-text);
}

.intro .hint {
  font-size: 0.9rem;
  color: var(--color-text-soft);
  font-style: italic;
}

.theory-selector {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border-soft);
}

.theory-btn {
  padding: 0.55rem 1rem;
  font-size: 0.875rem;
  font-family: inherit;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  color: var(--color-text);
  font-weight: 500;
}

.theory-btn:hover {
  background: var(--color-bg-alt);
  border-color: var(--color-text-soft);
}

.theory-btn.active {
  background: var(--color-active-bg);
  border-color: var(--color-active);
  color: var(--color-active);
}

.theory-btn.compare-btn {
  margin-left: auto;
  background: var(--color-bg-alt);
}

.view {
  display: none;
}

.view.active {
  display: block;
}

.theory-info {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow-soft);
}

.theory-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

#theory-name {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-text);
}

#theory-year {
  font-size: 0.875rem;
  color: var(--color-text-soft);
  font-style: italic;
}

#theory-claim {
  color: var(--color-text-muted);
  line-height: 1.65;
  font-size: 0.95rem;
}

.brain-container {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 1rem;
  margin-bottom: 1rem;
  overflow: hidden;
  box-shadow: var(--shadow-soft);
}

@media (prefers-color-scheme: dark) {
  .brain-container { background: #2A2A26; }
}

.struct {
  cursor: pointer;
  transition: opacity 0.4s ease;
}

.struct.dim { opacity: 0.18; }
.struct.active { opacity: 1; }

.struct-inner-label {
  pointer-events: none;
  font-family: var(--font-sans);
}

.path-arrow {
  fill: none;
  stroke: var(--color-active);
  stroke-width: 2.5;
  stroke-linecap: round;
  opacity: 0;
  transition: opacity 0.5s ease;
}

.path-arrow.show { opacity: 0.9; }

.flow-dot {
  fill: var(--color-flow);
  opacity: 0;
}

.flow-dot.show {
  opacity: 1;
  animation: flow var(--flow-dur, 2.4s) linear infinite;
}

@keyframes flow {
  0% { offset-distance: 0%; opacity: 0; }
  10% { opacity: 1; }
  90% { opacity: 1; }
  100% { offset-distance: 100%; opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .flow-dot.show {
    animation: none;
    opacity: 0.6;
  }
}

.leader-line {
  stroke: var(--color-text-soft);
  stroke-width: 0.5;
  stroke-dasharray: 2 2;
  opacity: 0.7;
}

.leader-label {
  font-family: var(--font-sans);
  font-size: 11px;
  fill: var(--color-text);
  font-weight: 500;
}

.leader-label-secondary {
  font-family: var(--font-sans);
  font-size: 10px;
  fill: var(--color-text-muted);
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
  align-items: center;
}

.control-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.9rem;
  font-size: 0.85rem;
  font-family: inherit;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  color: var(--color-text);
  font-weight: 500;
}

.control-btn:hover:not(:disabled) {
  background: var(--color-bg-alt);
  border-color: var(--color-text-soft);
}

.control-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.control-btn.primary {
  background: var(--color-active);
  border-color: var(--color-active);
  color: white;
}

.control-btn.primary:hover:not(:disabled) {
  background: var(--color-active);
  filter: brightness(1.1);
}

.step-counter {
  margin-left: auto;
  font-size: 0.8rem;
  color: var(--color-text-soft);
  font-style: italic;
}

.step-trail {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.step-pill {
  padding: 0.35rem 0.75rem;
  font-size: 0.8rem;
  background: var(--color-bg-alt);
  border-radius: 20px;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
}

.step-pill:hover {
  background: var(--color-border-soft);
}

.step-pill.current {
  background: var(--color-active-bg);
  color: var(--color-active);
  border-color: var(--color-active);
  font-weight: 500;
}

.hover-info {
  background: var(--color-bg-alt);
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  margin-bottom: 1.5rem;
  font-size: 0.875rem;
  min-height: 2.5rem;
  line-height: 1.5;
  color: var(--color-text-muted);
}

.hover-info .hover-hint {
  font-style: italic;
  color: var(--color-text-soft);
}

.hover-info strong {
  color: var(--color-text);
  font-weight: 500;
}

.glossary, .references {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  margin-bottom: 1rem;
  overflow: hidden;
}

.glossary summary, .references summary {
  padding: 1rem 1.25rem;
  cursor: pointer;
  font-weight: 500;
  font-size: 0.95rem;
  user-select: none;
  list-style: none;
  position: relative;
  padding-right: 2.5rem;
}

.glossary summary::-webkit-details-marker,
.references summary::-webkit-details-marker { display: none; }

.glossary summary::after, .references summary::after {
  content: "+";
  position: absolute;
  right: 1.25rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.2rem;
  color: var(--color-text-soft);
  transition: transform var(--transition);
}

.glossary[open] summary::after, .references[open] summary::after {
  content: "−";
}

.glossary-content, .references-content {
  padding: 0 1.25rem 1.25rem;
  border-top: 1px solid var(--color-border-soft);
  padding-top: 1rem;
}

.glossary-item {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--color-border-soft);
}

.glossary-item:last-child { border-bottom: none; }

.glossary-item h4 {
  font-size: 0.95rem;
  font-weight: 500;
  margin-bottom: 0.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.glossary-color-dot {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.glossary-item .role {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.55;
  margin-bottom: 0.4rem;
}

.glossary-item .ref {
  font-size: 0.78rem;
  color: var(--color-text-soft);
  font-style: italic;
}

.references-content p {
  font-size: 0.85rem;
  margin-bottom: 0.6rem;
  color: var(--color-text-muted);
  line-height: 1.55;
  text-indent: -1.5rem;
  padding-left: 1.5rem;
}

.compare-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}

.compare-selector {
  flex: 1;
  min-width: 180px;
}

.compare-selector label {
  display: block;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.3rem;
}

.compare-selector select {
  width: 100%;
  padding: 0.55rem 0.75rem;
  font-size: 0.9rem;
  font-family: inherit;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  cursor: pointer;
}

.compare-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.compare-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 1rem;
  box-shadow: var(--shadow-soft);
}

.compare-panel h3 {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.compare-panel .year {
  font-size: 0.8rem;
  color: var(--color-text-soft);
  font-style: italic;
  margin-bottom: 0.75rem;
}

.compare-panel .compare-claim {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.55;
  margin-bottom: 0.75rem;
}

.compare-panel svg {
  width: 100%;
  height: auto;
}

.site-footer {
  margin-top: 4rem;
  padding: 2rem 0;
  border-top: 1px solid var(--color-border-soft);
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-soft);
}

.site-footer p { margin-bottom: 0.25rem; }

.footer-note { font-style: italic; }

@media (max-width: 768px) {
  .site-header { padding: 1.5rem 0 1rem; }
  .site-header h1 { font-size: 1.4rem; }
  .container { padding: 0 1rem; }
  .theory-btn.compare-btn { margin-left: 0; width: 100%; margin-top: 0.5rem; }
  .compare-grid { grid-template-columns: 1fr; }
  .controls { flex-direction: row; }
  .step-counter { width: 100%; margin-left: 0; margin-top: 0.5rem; text-align: center; }
}

@media (max-width: 480px) {
  .theory-selector { gap: 0.35rem; }
  .theory-btn { padding: 0.45rem 0.75rem; font-size: 0.8rem; }
  .control-btn { font-size: 0.8rem; padding: 0.45rem 0.7rem; }
}