.app-shell {
  position: relative;
  width: min(100%, 1220px);
  margin: 0 auto;
  padding: calc(16px + env(safe-area-inset-top)) 12px calc(84px + env(safe-area-inset-bottom));
  z-index: 2;
}

.ocean-bg,
.wave-overlay {
  position: fixed;
  inset: 0;
  pointer-events: none;
}

.ocean-bg {
  z-index: 0;
  background:
    radial-gradient(circle at 80% 10%, rgba(34, 211, 238, 0.18), transparent 32%),
    radial-gradient(circle at 10% 90%, rgba(14, 31, 58, 0.6), transparent 38%),
    linear-gradient(180deg, var(--color-bg), var(--color-bg-soft));
}

.wave-overlay {
  z-index: 1;
  opacity: 0.35;
  background-image:
    repeating-linear-gradient(165deg, rgba(133, 197, 238, 0.08) 0, rgba(133, 197, 238, 0.08) 2px, transparent 2px, transparent 24px);
}

.content-grid {
  display: grid;
  gap: 12px;
}

.subpages {
  display: grid;
  gap: 12px;
}

.bottom-nav {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 6px;
  z-index: 15;
  background: rgba(5, 14, 28, 0.92);
  border-top: 1px solid rgba(94, 174, 224, 0.25);
  backdrop-filter: blur(12px);
  padding: 8px 8px calc(8px + env(safe-area-inset-bottom));
}

@media (min-width: 768px) {
  .app-shell {
    padding-left: 18px;
    padding-right: 18px;
  }
}

@media (min-width: 1024px) {
  .content-grid {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
}

@media (min-width: 1280px) {
  .content-grid {
    grid-template-columns: 1.3fr 1fr;
  }
}