/* The Trade-Off — black canvas, vibrant palette */
:root {
  --bg: #000000;
  --text: #f0f0f5;
  --text-muted: #8888a0;
  --cyan: #00e5ff;
  --magenta: #ff2d95;
  --amber: #ffb020;
  --teal: #00e676;
  --violet: #b388ff;
  --font-display: "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-mono: "Cascadia Code", "Consolas", monospace;
  --section-pad: clamp(2rem, 6vw, 5rem);
  --max-width: 1200px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-display);
  font-size: clamp(1rem, 1.1vw + 0.85rem, 1.125rem);
  line-height: 1.65;
  overflow-x: hidden;
}

/* Progress bar */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--cyan), var(--magenta), var(--teal));
  z-index: 1000;
  transition: width 0.1s linear;
}

/* Sections */
section {
  min-height: 100vh;
  padding: var(--section-pad);
  position: relative;
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
}

.section-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 4vw, 4rem);
  align-items: center;
  min-height: calc(100vh - var(--section-pad) * 2);
}

@media (max-width: 900px) {
  .section-grid {
    grid-template-columns: 1fr;
    min-height: auto;
  }
}

/* Title card */
#title {
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-height: 100vh;
}

.title-card h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 0 0 0.5rem;
  background: linear-gradient(135deg, var(--cyan), var(--magenta));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.title-card .subtitle {
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  color: var(--text-muted);
  margin-bottom: 2rem;
}

.title-card .through-line {
  max-width: 640px;
  margin: 0 auto;
  font-size: clamp(1rem, 1.5vw, 1.2rem);
  color: var(--violet);
  font-style: italic;
  border-top: 1px solid #222;
  padding-top: 2rem;
}

.scroll-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  color: var(--text-muted);
  font-size: 0.85rem;
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* Chapter typography */
.chapter-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--cyan);
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.2;
  margin: 0 0 1.5rem;
  letter-spacing: -0.02em;
}

.insight {
  font-size: clamp(1.1rem, 2vw, 1.35rem);
  color: var(--teal);
  font-weight: 600;
  margin-bottom: 1.5rem;
  border-left: 3px solid var(--teal);
  padding-left: 1rem;
}

.narrative-block p {
  margin: 0 0 1rem;
  opacity: 0;
  transform: translateY(20px);
}

.narrative-block p.visible {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

/* Stats grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.stat-card {
  background: #0a0a0f;
  border: 1px solid #1a1a28;
  border-radius: 8px;
  padding: 1rem;
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease, border-color 0.3s;
}

.stat-card.visible {
  opacity: 1;
  transform: translateY(0);
}

.stat-card:hover {
  border-color: var(--cyan);
}

.stat-value {
  font-size: 1.75rem;
  font-weight: 800;
  font-family: var(--font-mono);
}

.stat-value.cyan { color: var(--cyan); }
.stat-value.magenta { color: var(--magenta); }
.stat-value.amber { color: var(--amber); }
.stat-value.teal { color: var(--teal); }
.stat-value.violet { color: var(--violet); }

.stat-label {
  font-size: 0.8rem;
  color: var(--text);
  margin-top: 0.25rem;
}

.stat-note {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 0.35rem;
}

/* Equivalence box */
.equiv-box {
  background: linear-gradient(135deg, #0d0d14 0%, #12101a 100%);
  border: 1px solid #2a2040;
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}

.equiv-box h4 {
  margin: 0 0 0.75rem;
  color: var(--violet);
  font-size: 1rem;
}

.equiv-box p {
  margin: 0.35rem 0;
  color: var(--text-muted);
}

/* Visual panels */
.visual-panel {
  position: relative;
  min-height: 420px; /* TRANG ADDED THIS */
  display: flex;
  align-items: center;
  justify-content: center;
  background: #050508;
  border: 1px solid #151520;
  border-radius: 16px;
  overflow: hidden;
}

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

/* Hook — chat UI */
.chat-ui {
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
}

.chat-bubble {
  border-radius: 12px;
  padding: 1rem 1.25rem;
  margin-bottom: 1rem;
  font-size: 0.95rem;
}

.chat-bubble.user {
  background: #1a1a28;
  border: 1px solid #333;
  margin-left: 2rem;
}

.chat-bubble.ai {
  background: linear-gradient(135deg, #0a2030, #101828);
  border: 1px solid var(--cyan);
  margin-right: 2rem;
  color: var(--cyan);
}

.chat-label {
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.dissolve-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 2rem;
  opacity: 0;
}

.dissolve-grid.visible {
  opacity: 1;
}

.dissolve-item {
  text-align: center;
  padding: 1rem;
  border-radius: 10px;
  background: #0a0a12;
  border: 1px dashed #333;
  opacity: 0;
  transform: scale(0.8);
  transition: opacity 0.5s, transform 0.5s, border-color 0.3s;
}

.dissolve-item.visible {
  opacity: 1;
  transform: scale(1);
}

.dissolve-item.cyan { border-color: var(--cyan); color: var(--cyan); }
.dissolve-item.teal { border-color: var(--teal); color: var(--teal); }
.dissolve-item.violet { border-color: var(--violet); color: var(--violet); }
.dissolve-item.magenta { border-color: var(--magenta); color: var(--magenta); }
.dissolve-item.amber { border-color: var(--amber); color: var(--amber); }

.dissolve-icon {
  font-size: 1.75rem;
  margin-bottom: 0.35rem;
}

.dissolve-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* Hourglass counter */
.hourglass-counter {
  text-align: center;
  margin-top: 1rem;
}

.counter-display {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  color: var(--teal);
}

.counter-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.15em;
}

.emotional-beat {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--teal);
  text-align: center;
  margin-top: 2rem;
  opacity: 0;
}

.emotional-beat.visible {
  opacity: 1;
  animation: pulse-glow 2s ease-in-out infinite;
}

@keyframes pulse-glow {
  0%, 100% { text-shadow: 0 0 20px rgba(0, 230, 118, 0.3); }
  50% { text-shadow: 0 0 40px rgba(0, 230, 118, 0.6); }
}

/* Morph energy bar */
.energy-bar-wrap {
  width: 100%;
  max-width: 320px;
  margin: 1rem auto 0;
}

.energy-bar-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.energy-bar {
  height: 8px;
  background: #1a1a28;
  border-radius: 4px;
  overflow: hidden;
}

.energy-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--teal), var(--amber), var(--magenta));
  border-radius: 4px;
  width: 0%;
  transition: width 0.6s ease;
}

.morph-label {
  text-align: center;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--cyan);
  margin-top: 0.75rem;
}

/* Reservoir */
.reservoir-panel {
  transition: background 1s ease;
}

.reservoir-panel.phase-natural {
  background: linear-gradient(180deg, #050508 0%, #0a1520 100%);
}

.reservoir-panel.phase-industrial {
  background: linear-gradient(180deg, #050508 0%, #1a1a1a 100%);
}

/* Exchange */
.exchange-wrap {
  width: 100%;
  min-height: 400px;
}

/* Ledger */
.ledger-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

@media (max-width: 700px) {
  .ledger-grid {
    grid-template-columns: 1fr;
  }
}

.ledger-col h3 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 1rem;
}

.ledger-col.costs h3 { color: var(--magenta); }
.ledger-col.benefits h3 { color: var(--teal); }

.ledger-group {
  margin-bottom: 1.5rem;
}

.ledger-group-title {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 0.5rem;
}

.ledger-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.5rem 0;
  border-bottom: 1px solid #151520;
  opacity: 0;
  transform: translateX(-10px);
  transition: opacity 0.4s, transform 0.4s;
}

.ledger-col.benefits .ledger-row {
  transform: translateX(10px);
}

.ledger-row.visible {
  opacity: 1;
  transform: translateX(0);
}

.ledger-row-value {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
}

.ledger-row-value.cost { color: var(--magenta); }
.ledger-row-value.benefit { color: var(--teal); }

/* Finale */
#finale {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--section-pad);
}

.finale-narrative {
  max-width: 720px;
  margin-bottom: 3rem;
}

.finale-narrative p {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  margin: 0 0 1.25rem;
  opacity: 1;
  transition: opacity 1.5s ease;
}

.finale-narrative.fade-out p {
  opacity: 0;
}

.finale-counters {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
  width: 100%;
  max-width: 900px;
}

@media (max-width: 600px) {
  .finale-counters {
    grid-template-columns: 1fr;
  }
}

.finale-counter {
  padding: 1.5rem;
  background: #0a0a0f;
  border-radius: 12px;
  border: 1px solid #1a1a28;
}

.finale-counter.teal { border-color: var(--teal); }
.finale-counter.cyan { border-color: var(--cyan); }
.finale-counter.violet { border-color: var(--violet); }
.finale-counter.magenta { border-color: var(--magenta); }

.finale-counter-value {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4vw, 2.5rem);
  font-weight: 800;
  line-height: 1.2;
}

.finale-counter.teal .finale-counter-value { color: var(--teal); }
.finale-counter.cyan .finale-counter-value { color: var(--cyan); }
.finale-counter.violet .finale-counter-value { color: var(--violet); }
.finale-counter.magenta .finale-counter-value { color: var(--magenta); }

.finale-counter-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.finale-arrow {
  font-size: 1.25rem;
  margin-left: 0.25rem;
}

/* Sources footnote */
.sources {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid #151520;
  font-size: 0.7rem;
  color: var(--text-muted);
}

.sources li {
  margin: 0.25rem 0;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }

  .scroll-hint {
    animation: none;
  }
}