/* The pencil eddies behind the workspace shell (components/backdrop.js): one canvas of streamlines
   drawn once, one of short strokes moving along them. It fades in over 900 ms and goes at once when
   the shell goes. No pointer, no colour of its own: ink on the page ground. */
.backdrop { position: fixed; inset: 0; z-index: -1; pointer-events: none; opacity: 0; overflow: hidden; background: var(--bg); }
.backdrop.is-on { opacity: 1; transition: opacity 900ms ease; }
.backdrop canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
@media (prefers-reduced-motion: reduce) { .backdrop.is-on { transition: none; } }
@media print, (forced-colors: active) { .backdrop { display: none; } }