/* —  — cinematic minimal —  — */
:root {
  --ink: #0a0a0a;
  --paper: #f8f8f6;
  --gold: #d4af37;
  --gold-bright: #f2e7d0;
  --ink-2: #1a1a1a;
  --transition: cubic-bezier(0.76, 0, 0.24, 1);
}

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

body {
  font-family: "DM Mono", monospace;
  background: var(--ink);
  color: var(--paper);
  overflow-x: hidden;
  overflow-y: scroll;
  -webkit-font-smoothing: antialiased;
}

#bar {
  position: fixed;
  top: 0; left: 0;
  height: 2px;
  width: 100%;
  background: rgba(212, 175, 55, 0.15);
  z-index: 9999;
  transform-origin: 0 50%;
}

#bar > div {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--gold), var(--gold-bright));
  transition: width 0.1s linear;
}

#webgl {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 1;
}

.chapter {
  position: relative;
  z-index: 2;
  height: 100vh;
  width: 100vw;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.chapter:nth-child(even) { background: var(--ink-2); }

.chapter__frame {
  position: absolute;
  left: 120px;
  top: 50%;
  transform: translateY(-50%);
  opacity: 0.12;
  transition: opacity 0.4s var(--transition);
}

.chapter--active .chapter__frame { opacity: 0.8; }

.chapter__num {
  font-size: 1.8rem;
  letter-spacing: 0.3em;
  font-weight: 200;
  color: var(--gold);
}

.chapter__title {
  font-size: clamp(2rem, 4vw + 1rem, 4.5rem);
  letter-spacing: -0.03em;
  font-weight: 400;
  line-height: 1;
  margin-top: 0.6em;
}

.chapter__sub {
  font-size: 1.1rem;
  margin-top: 1.2em;
  opacity: 0.6;
}

@media (max-width: 768px) {
  .chapter__frame { left: 40px; }
  .chapter__num { font-size: 1.4rem; }
  .chapter__title { font-size: clamp(1.6rem, 5vw, 3rem); }
}

.js-anim .chapter__frame {
  opacity: 0;
  transform: translateY(-50%) translateX(-20px);
}

.js-anim .chapter__frame.is-visible {
  opacity: 0.6;
  transform: translateY(-50%) translateX(0);
}

.js-anim .chapter--active .chapter__frame { opacity: 0.8; }