/* Decorative canvas stays behind content and never intercepts interaction. */
.background-crab { position: fixed; inset: 0; z-index: -1; width: 100%; height: 100%; pointer-events: none; opacity: .48; }
body { isolation: isolate; }
html[data-theme=dark] .background-crab { opacity: .12; }

@media (max-width: 850px) {
  .background-crab { display: none; }
}