/* ============================================
   PROCEDURAL v2 — Shell Styles
   Continuous scroll + Floating nav + TOC panel
   ============================================ */


/* ============================================
   SHELL LAYOUT
   ============================================ */
.shell {
  position: relative;
  min-height: 100vh;
}

.content {
  position: relative;
}


/* ============================================
   CHAPTER WRAPPER
   ============================================ */
.chapter {
  position: relative;
}


/* ============================================
   CHAPTER HERO GRADIENT OVERRIDES
   (base hero styles come from lib/base.css)
   ============================================ */
[data-chapter="1"] > .hero {
  background: radial-gradient(ellipse at 50% 40%, rgba(200,160,100,0.04) 0%, var(--bg) 70%);
}
[data-chapter="2"] > .hero {
  background: radial-gradient(ellipse at 50% 40%, rgba(107,163,190,0.04) 0%, var(--bg) 70%);
}
[data-chapter="3"] > .hero {
  background: radial-gradient(ellipse at 50% 40%, rgba(155,125,184,0.04) 0%, var(--bg) 70%);
}
[data-chapter="4"] > .hero {
  background: radial-gradient(ellipse at 50% 40%, rgba(126,200,150,0.04) 0%, var(--bg) 70%);
}


/* ============================================
   LANDING HERO (Ch 0)
   ============================================ */
.landing-hero {
  height: 100vh;
  position: relative;
  overflow: hidden;
  background: #1A1816;
}

.landing-hero__content {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  pointer-events: none;
  z-index: 2;
}

.landing-hero__title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 7vw, 6.5rem);
  font-weight: 400;
  letter-spacing: 0.04em;
  color: var(--text-primary);
  text-align: center;
  line-height: 1.1;
  text-shadow: 0 0 60px rgba(200, 160, 100, 0.15),
               0 0 120px rgba(200, 160, 100, 0.06);
  opacity: 0;
  animation: landingFadeUp 2s 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.landing-hero__subtitle {
  font-size: clamp(0.9rem, 2vw, 1.35rem);
  font-weight: 300;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-top: var(--sp-md);
  text-align: center;
  opacity: 0;
  animation: landingFadeUp 2s 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.landing-hero__date {
  font-size: clamp(0.7rem, 1.2vw, 0.9rem);
  font-weight: 300;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-top: var(--sp-lg);
  text-align: center;
  opacity: 0;
  animation: landingFadeUp 2s 1.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.landing-hero__scroll {
  position: absolute;
  bottom: var(--sp-2xl);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-sm);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  z-index: 2;
  pointer-events: none;
  opacity: 0;
  animation: landingFadeUp 0.8s 2s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.landing-hero__scroll-dot {
  animation: scrollBob 2s ease-in-out infinite;
}

@keyframes scrollBob {
  0%, 100% { cy: 8; }
  50% { cy: 16; }
}

@keyframes landingFadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}


/* ============================================
   INTRO SCREENS (Ch 0)
   ============================================ */
.intro-screen {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 80px 40px;
  position: relative;
  overflow: hidden;
}

.intro-screen .intro-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

.intro-screen {
  background: linear-gradient(180deg, #1A1816 0%, var(--surface) 100%);
}

.intro-screen .section-content {
  opacity: 1 !important;
  transform: none !important;
  transition: none !important;
  position: relative;
  z-index: 1;
}

/* -- Screen 1: Thesis -- */
.intro-thesis {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.intro-thesis .intro-line {
  transition: opacity 1s cubic-bezier(0.16, 1, 0.3, 1),
              transform 1s cubic-bezier(0.16, 1, 0.3, 1);
}

.intro-l1 {
  font-family: var(--font-display);
  font-size: clamp(44px, 7.5vw, 92px);
  font-weight: 400;
  font-style: italic;
  line-height: 1.15;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--accent), #D4A853);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  opacity: 0;
  transform: translateY(50px);
}

.intro-l2 {
  font-size: clamp(28px, 4.5vw, 58px);
  font-weight: 200;
  line-height: 1.35;
  color: rgba(232, 226, 218, 0.50);
  letter-spacing: -0.02em;
  opacity: 0;
  transform: translateX(-80px);
}

.intro-l3 {
  font-size: clamp(28px, 4.5vw, 58px);
  font-weight: 200;
  line-height: 1.35;
  color: rgba(232, 226, 218, 0.40);
  letter-spacing: -0.02em;
  opacity: 0;
  transform: translateX(80px);
}

.intro-l4 {
  font-size: clamp(44px, 7.5vw, 92px);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.04em;
  color: rgba(232, 226, 218, 0.95);
  opacity: 0;
  transform: scale(0.8) translateY(20px);
}

/* Connectors between lines */
.intro-l1::after,
.intro-l2::after,
.intro-l3::after {
  content: '';
  display: block;
  width: 48px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(200, 160, 100, 0.25), transparent);
  margin: 6px auto;
  opacity: 0;
  transition: opacity 0.8s ease;
}

.intro-thesis.revealed .intro-l1 { opacity: 1; transform: translateY(0); transition-delay: 0s; }
.intro-thesis.revealed .intro-l2 { opacity: 1; transform: translateX(0); transition-delay: 0.2s; }
.intro-thesis.revealed .intro-l3 { opacity: 1; transform: translateX(0); transition-delay: 0.4s; }
.intro-thesis.revealed .intro-l4 { opacity: 1; transform: scale(1) translateY(0); transition-delay: 0.65s; }
.intro-thesis.revealed .intro-l1::after { opacity: 1; transition-delay: 1.0s; }
.intro-thesis.revealed .intro-l2::after { opacity: 1; transition-delay: 1.15s; }
.intro-thesis.revealed .intro-l3::after { opacity: 1; transition-delay: 1.3s; }

/* -- Screen 2: Transfer -- */
.intro-transfer {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 100px;
  max-width: 1100px;
  width: 100%;
  flex-wrap: wrap;
}

.transfer-col {
  flex: 0 1 auto;
  max-width: 360px;
  opacity: 0;
  transition: opacity 1s cubic-bezier(0.16, 1, 0.3, 1),
              transform 1s cubic-bezier(0.16, 1, 0.3, 1);
}

.transfer-human {
  text-align: right;
  transform: translateX(-50px);
}

.transfer-machine {
  text-align: left;
  transform: translateX(50px);
}

.transfer-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 3px;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.transfer-human .transfer-label { color: rgba(255, 200, 150, 0.6); }
.transfer-machine .transfer-label { color: rgba(200, 160, 100, 0.6); }

.transfer-term {
  font-size: clamp(24px, 3.5vw, 44px);
  font-weight: 300;
  line-height: 1.4;
  letter-spacing: -0.02em;
}

.transfer-human .transfer-term { color: rgba(255, 240, 225, 0.8); }

.transfer-machine .transfer-term {
  font-family: var(--font-mono);
  font-size: clamp(18px, 2.5vw, 32px);
  font-weight: 400;
  color: rgba(232, 226, 218, 0.7);
}

.intro-transfer.revealed .transfer-human {
  opacity: 1; transform: translateX(0); transition-delay: 0s;
}

.intro-transfer.revealed .transfer-machine {
  opacity: 1; transform: translateX(0); transition-delay: 0.5s;
}

/* -- Screen 3: Definition -- */
.intro-define {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 48px;
}

.define-word {
  font-family: var(--font-display);
  font-size: clamp(48px, 9vw, 128px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  background: linear-gradient(135deg, var(--accent) 0%, #D4A853 33%, #F0D890 66%, var(--accent) 100%);
  background-size: 300% 100%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: introGradientFlow 10s ease infinite;
  opacity: 0;
  transform: scale(0.85);
  transition: opacity 1.2s cubic-bezier(0.16, 1, 0.3, 1),
              transform 1.2s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes introGradientFlow {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.define-body {
  max-width: 660px;
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 1.2s cubic-bezier(0.16, 1, 0.3, 1),
              transform 1.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.define-body p {
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 2;
  margin-bottom: 10px;
  color: rgba(166, 153, 133, 0.8);
}

.define-body strong {
  color: rgba(232, 226, 218, 0.9);
  font-weight: 600;
}

.define-body .hl {
  color: rgba(200, 160, 100, 0.7);
  opacity: 0;
  transition: opacity 0.5s ease, color 0.3s ease;
}

.define-body .hl:hover {
  color: rgba(200, 160, 100, 0.95);
}

.intro-define.revealed .define-word {
  opacity: 1; transform: scale(1); transition-delay: 0s;
}

.intro-define.revealed .define-body {
  opacity: 1; transform: translateY(0); transition-delay: 0.35s;
}

.intro-define.revealed .define-body .hl { opacity: 1; }

/* -- Intro responsive -- */
@media (max-width: 768px) {
  .intro-transfer { flex-direction: column; gap: 48px; }
  .transfer-human, .transfer-machine { text-align: center; }
  .transfer-human { transform: translateY(-30px); }
  .transfer-machine { transform: translateY(30px); }
  .intro-transfer.revealed .transfer-human,
  .intro-transfer.revealed .transfer-machine { transform: translateY(0); }
}


/* ============================================
   DEMO SECTIONS — Full-viewport interactive
   ============================================ */
.demo-section {
  min-height: 100vh;
  position: relative;
  display: flex;
  flex-direction: column;
}

.demo-section__header {
  padding: var(--sp-2xl) var(--sp-xl) var(--sp-lg);
  text-align: center;
  max-width: 700px;
  margin: 0 auto;
  will-change: transform, opacity;
}

.demo-section__label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--sp-sm);
  display: block;
}

.demo-section__header h2 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 400;
  color: var(--text-primary);
  line-height: 1.2;
  margin-bottom: var(--sp-md);
}

.demo-section__header p {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.demo-section__canvas {
  flex: 1;
  min-height: 500px;
  position: relative;
  overflow: hidden;
}


/* ---- Demo Bridge (between demos) ---- */
.demo-bridge {
  padding: var(--sp-3xl) var(--sp-xl);
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
  will-change: transform, opacity;
}

.demo-bridge p {
  font-family: var(--font-display);
  font-size: clamp(1.125rem, 2vw, 1.5rem);
  font-style: italic;
  color: var(--text-secondary);
  line-height: 1.6;
}


/* ============================================
   EPILOGUE
   ============================================ */
.epilogue__line {
  will-change: transform, opacity;
}


/* ============================================
   TOC SIDE PANEL
   ============================================ */
.toc-panel {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 380px;
  max-width: 85vw;
  z-index: 300;
  background: rgba(26, 24, 22, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-right: 1px solid var(--border-subtle);
  transform: translateX(-100%);
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  overflow-y: auto;
  display: flex;
  flex-direction: column;

  /* Custom scrollbar */
  scrollbar-width: thin;
  scrollbar-color: rgba(61, 54, 48, 0.6) transparent;
}

html[data-theme="light"] .toc-panel {
  background: rgba(245, 242, 238, 0.88);
  scrollbar-color: rgba(209, 201, 190, 0.7) transparent;
}

.toc-panel::-webkit-scrollbar { width: 6px; }
.toc-panel::-webkit-scrollbar-track { background: transparent; }
.toc-panel::-webkit-scrollbar-thumb { background: rgba(61, 54, 48, 0.6); border-radius: 3px; }
.toc-panel::-webkit-scrollbar-thumb:hover { background: rgba(166, 153, 133, 0.5); }

html[data-theme="light"] .toc-panel::-webkit-scrollbar-thumb { background: rgba(209, 201, 190, 0.7); }
html[data-theme="light"] .toc-panel::-webkit-scrollbar-thumb:hover { background: rgba(160, 120, 48, 0.4); }

.shell.is-panel-open .toc-panel {
  transform: translateX(0);
}

.toc-backdrop {
  position: fixed;
  inset: 0;
  z-index: 250;
  background: rgba(0, 0, 0, 0.4);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

.shell.is-panel-open .toc-backdrop {
  opacity: 1;
  pointer-events: auto;
}


/* ---- Panel Header ---- */
.toc-panel__header {
  padding: var(--sp-2xl) var(--sp-xl) var(--sp-lg);
}

.toc-panel__title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  display: block;
  margin-bottom: 4px;
}

.toc-panel__subtitle {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  display: block;
}

.toc-panel__divider {
  height: 1px;
  background: var(--border-subtle);
  margin: 0 var(--sp-xl);
}


/* ---- Panel Navigation ---- */
.toc-panel__nav {
  padding: var(--sp-lg) var(--sp-md);
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

.toc-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: var(--sp-md) var(--sp-md);
  border-radius: var(--radius-md);
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
  border: 1px solid transparent;
}

.toc-item:hover {
  background: var(--surface-hover);
  border-color: var(--border-subtle);
}

.toc-item.is-active {
  background: var(--surface);
  border-color: rgba(200, 160, 100, 0.15);
}

.toc-item__num {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  transition: color 0.2s;
}

.toc-item.is-active .toc-item__num {
  color: var(--accent);
}

.toc-item__title {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  transition: color 0.2s;
}

.toc-item.is-active .toc-item__title {
  color: var(--accent);
}

.toc-item__demos {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-top: 2px;
}

.toc-demo {
  font-family: var(--font-mono);
  font-size: 0.5625rem;
  letter-spacing: 0.04em;
  padding: 2px 8px;
  background: var(--bg);
  border: 1px solid var(--border-subtle);
  border-radius: 999px;
  color: var(--text-muted);
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}

.toc-demo:hover {
  color: var(--accent);
  border-color: rgba(200, 160, 100, 0.3);
  background: rgba(200, 160, 100, 0.06);
}


/* ============================================
   FLOATING CHAPTER NAV
   (5 dots: Intro + 4 chapters)
   ============================================ */
.chapter-nav {
  position: fixed;
  z-index: 200;
  display: flex;
  align-items: center;
  gap: 6px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.chapter-nav.is-visible {
  opacity: 1;
  pointer-events: auto;
}

/* Pill background (::before pseudo) */
.chapter-nav::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 999px;
  background: rgba(26, 24, 22, 0.55);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--border-subtle);
  opacity: 0;
  transition: opacity 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: none;
  z-index: -1;
}

html[data-theme="light"] .chapter-nav::before {
  background: rgba(245, 242, 238, 0.7);
}

.chapter-nav.is-horizontal::before {
  opacity: 1;
}

.chapter-nav--pill-hidden::before {
  opacity: 0 !important;
}

/* Vertical (left sidebar) */
.chapter-nav.is-vertical {
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  flex-direction: column;
}

/* Horizontal (bottom bar) */
.chapter-nav.is-horizontal {
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  flex-direction: row;
  border-radius: 999px;
  padding: 6px 12px;
}

/* TOC / Back button */
.chapter-nav__back {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  border: 1px solid var(--border-subtle);
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
  flex-shrink: 0;
}

.chapter-nav__back:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(200,160,100,0.06);
}

/* Divider */
.chapter-nav__divider {
  flex-shrink: 0;
}

.chapter-nav.is-vertical .chapter-nav__divider {
  width: 16px;
  height: 1px;
  background: var(--border-subtle);
  margin: 2px 0;
}

.chapter-nav.is-horizontal .chapter-nav__divider {
  width: 1px;
  height: 16px;
  background: var(--border-subtle);
  margin: 0 2px;
}

/* Dots container */
.chapter-nav__dots {
  display: flex;
  align-items: center;
  position: relative;
}

.chapter-nav.is-vertical .chapter-nav__dots {
  flex-direction: column;
  gap: 8px;
}

.chapter-nav.is-horizontal .chapter-nav__dots {
  flex-direction: row;
  gap: 8px;
}

/* Individual dot */
.chapter-nav__dot {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 0;
}

.chapter-nav__circle {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border);
  transition: background 0.3s, transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.3s;
}

.chapter-nav__dot.is-current .chapter-nav__circle {
  background: var(--accent);
  transform: scale(1.3);
  box-shadow: 0 0 8px rgba(200,160,100,0.4);
}

.chapter-nav__dot:hover .chapter-nav__circle {
  background: var(--text-secondary);
  transform: scale(1.2);
}

.chapter-nav__dot.is-current:hover .chapter-nav__circle {
  background: var(--accent);
}

/* Hover labels */
.chapter-nav__label {
  position: absolute;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  padding: 4px 8px;
  border-radius: 4px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
  z-index: 10;
}

.chapter-nav.is-vertical .chapter-nav__label {
  left: 36px;
  top: 50%;
  transform: translateY(-50%) translateX(-4px);
}

.chapter-nav.is-vertical .chapter-nav__dot:hover .chapter-nav__label {
  opacity: 1;
  transform: translateY(-50%) translateX(0);
}

.chapter-nav.is-horizontal .chapter-nav__label {
  bottom: 36px;
  left: 50%;
  transform: translateX(-50%) translateY(4px);
}

.chapter-nav.is-horizontal .chapter-nav__dot:hover .chapter-nav__label {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Progress bar */
.chapter-nav__progress {
  position: absolute;
  background: var(--accent);
  opacity: 0.25;
  border-radius: 1px;
  transition: width 0.15s linear, height 0.15s linear;
  pointer-events: none;
}

.chapter-nav.is-vertical .chapter-nav__progress {
  left: -4px;
  top: 0;
  width: 2px;
}

.chapter-nav.is-horizontal .chapter-nav__progress {
  bottom: -4px;
  left: 0;
  height: 2px;
}

/* Layout toggle */
.chapter-nav__toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: color 0.2s;
  flex-shrink: 0;
}

.chapter-nav__toggle:hover {
  color: var(--text-secondary);
}


/* ============================================
   HERO CONFIG — Avoid overlap with theme toggle
   ============================================ */
.hero-config-btn {
  right: 64px !important;
}

.hero-config-panel {
  right: 64px !important;
}


/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 768px) {
  .chapter-nav.is-vertical { left: 8px; }
  .chapter-nav.is-horizontal { bottom: 8px; }
  .chapter-nav__label { display: none; }
  .demo-section__header { padding: var(--sp-xl) var(--sp-md) var(--sp-md); }
  .demo-bridge { padding: var(--sp-2xl) var(--sp-md); }

  .toc-panel { width: 85vw; }

  .hero__content { padding: 0 var(--sp-md); }
}


/* ============================================
   LIGHT MODE OVERRIDES
   ============================================ */
html[data-theme="light"] .landing-hero {
  background: var(--bg);
}

html[data-theme="light"] .landing-hero__title {
  text-shadow: 0 0 60px rgba(160, 120, 48, 0.12),
               0 0 120px rgba(160, 120, 48, 0.05);
}

html[data-theme="light"] .intro-screen {
  background: linear-gradient(180deg, var(--bg) 0%, var(--surface) 100%);
}

html[data-theme="light"] .intro-l1 {
  background: linear-gradient(135deg, var(--accent), #8A6820);
  -webkit-background-clip: text;
  background-clip: text;
}

html[data-theme="light"] .intro-l2 {
  color: rgba(61, 54, 48, 0.50);
}

html[data-theme="light"] .intro-l3 {
  color: rgba(61, 54, 48, 0.40);
}

html[data-theme="light"] .intro-l4 {
  color: rgba(61, 54, 48, 0.92);
}

html[data-theme="light"] .intro-l1::after,
html[data-theme="light"] .intro-l2::after,
html[data-theme="light"] .intro-l3::after {
  background: linear-gradient(90deg, transparent, rgba(160, 120, 48, 0.30), transparent);
}

html[data-theme="light"] .transfer-human .transfer-label {
  color: rgba(160, 100, 40, 0.7);
}

html[data-theme="light"] .transfer-machine .transfer-label {
  color: rgba(138, 104, 32, 0.7);
}

html[data-theme="light"] .transfer-human .transfer-term {
  color: rgba(61, 54, 48, 0.85);
}

html[data-theme="light"] .transfer-machine .transfer-term {
  color: rgba(61, 54, 48, 0.75);
}

html[data-theme="light"] .define-word {
  background: linear-gradient(135deg, var(--accent) 0%, #8A6820 33%, #B08A40 66%, var(--accent) 100%);
  background-size: 300% 100%;
  -webkit-background-clip: text;
  background-clip: text;
}

html[data-theme="light"] .define-body p {
  color: rgba(115, 107, 95, 0.85);
}

html[data-theme="light"] .define-body strong {
  color: rgba(61, 54, 48, 0.92);
}

html[data-theme="light"] .define-body .hl {
  color: rgba(138, 104, 32, 0.8);
}

html[data-theme="light"] .define-body .hl:hover {
  color: rgba(138, 104, 32, 1);
}

html[data-theme="light"] .toc-backdrop {
  background: rgba(0, 0, 0, 0.15);
}

html[data-theme="light"] .toc-item.is-active {
  border-color: rgba(160, 120, 48, 0.2);
}

html[data-theme="light"] .toc-demo:hover {
  color: var(--accent);
  border-color: rgba(160, 120, 48, 0.35);
  background: rgba(160, 120, 48, 0.08);
}

html[data-theme="light"] .chapter-nav__dot.is-current .chapter-nav__circle {
  box-shadow: 0 0 8px rgba(160, 120, 48, 0.35);
}

html[data-theme="light"] .chapter-nav__back:hover {
  background: rgba(160, 120, 48, 0.08);
}