/* SALTA — underwater chapter. Near-fullscreen photograph in a rounded panel,
   copy sitting inside it. Light drifts across the water very slowly. */

.underwater { background: var(--deep); color: var(--white); }
.underwater__panel {
  position: relative;
  min-height: min(88svh, 780px);
  display: grid;
  align-items: end;
  border-radius: var(--r-xl);
  overflow: hidden;
  isolation: isolate;
}
.underwater__panel img {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  z-index: -2;
  scale: var(--uw-scale, 1.03);
  will-change: scale;
}
.underwater__panel::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: linear-gradient(to top, rgba(5, 43, 69, .88) 4%, rgba(5, 43, 69, .18) 55%, rgba(0, 111, 255, .18));
}
/* refracted light: one very slow, very cheap transform — no bubble particles */
.underwater__light {
  position: absolute;
  inset: -20%;
  z-index: -1;
  background: radial-gradient(45% 30% at 30% 10%, rgba(35, 229, 210, .30), transparent 70%),
              radial-gradient(35% 25% at 72% 4%, rgba(217, 255, 67, .16), transparent 70%);
  animation: salta-refract 16s var(--ease-in-out) infinite alternate;
  pointer-events: none;
}
@keyframes salta-refract {
  from { transform: translate3d(-3%, 0, 0) scale(1); opacity: .75; }
  to   { transform: translate3d(3%, 2%, 0) scale(1.08); opacity: 1; }
}

.underwater__copy {
  position: relative;
  display: grid;
  gap: 1.2rem;
  padding: clamp(1.5rem, 4vw, 3.5rem);
  max-width: 46rem;
}
.underwater__title {
  font-size: var(--t-huge);
  line-height: .88;
  letter-spacing: var(--track-huge);
  text-transform: uppercase;
}
.underwater__title .accent { color: var(--turq); }
.underwater__copy p { color: var(--white-70); max-width: 46ch; }

@media (prefers-reduced-motion: reduce) {
  .underwater__light { animation: none; }
}