#canvas-container, #ui-layer, #system-select-root, #topo-canvas {
    animation: scene-enter 260ms ease-out both;
    transition: opacity 160ms ease-out;
}
.scene-leaving #canvas-container,
.scene-leaving #ui-layer,
.scene-leaving #system-select-root,
.scene-leaving #topo-canvas { opacity: 0; }
@keyframes scene-enter { from { opacity: 0; } to { opacity: 1; } }
@media (prefers-reduced-motion: reduce) {
    #canvas-container, #ui-layer, #system-select-root, #topo-canvas {
        animation: none;
        transition: none;
    }
}