/* =============================================================================
   Ethereal Shadow — fondo animado detrás de las tarjetas de auth.
   Reimplementación CSS/SVG del componente React (sin framer-motion).
   La ondulación se logra con un filtro SVG (feTurbulence + feDisplacementMap)
   cuyo hueRotate se anima con SMIL (<animate>), más una capa de ruido.
   ============================================================================= */

.ethereal-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  background: var(--background);
  pointer-events: none;
}

/* Capa de la "sombra" enmascarada con la silueta orgánica.
   NOTA: se usa solo `blur` (GPU-barato). El filtro SVG feDisplacementMap se
   retiró porque WebKit/Safari lo computa en CPU a pantalla completa y se atasca;
   Chromium lo hacía en GPU. blur + deriva por transform va fluido en todos. */
.ethereal-bg__shape {
  position: absolute;
  inset: -80px;
  background-color: var(--muted-foreground);
  opacity: 0.5;
  filter: blur(60px);

  -webkit-mask-image: url('https://framerusercontent.com/images/ceBGguIpUU8luwByxuQz79t7To.png');
  mask-image: url('https://framerusercontent.com/images/ceBGguIpUU8luwByxuQz79t7To.png');
  -webkit-mask-size: cover;
  mask-size: cover;
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;
  -webkit-mask-position: center;
  mask-position: center;

  animation: ethereal-drift 18s ease-in-out infinite alternate;
}

@keyframes ethereal-drift {
  0%   { transform: translate(0, 0) scale(1); }
  50%  { transform: translate(2%, -2%) scale(1.05); }
  100% { transform: translate(-2%, 2%) scale(1); }
}

/* Capa de ruido sutil */
.ethereal-bg__noise {
  position: absolute;
  inset: 0;
  background-image: url('https://framerusercontent.com/images/g0QcWrxr87K0ufOxIUFBakwYA8.png');
  background-size: 240px;
  background-repeat: repeat;
  opacity: 0.5;
  mix-blend-mode: soft-light;
}

/* Respeta usuarios que prefieren menos movimiento */
@media (prefers-reduced-motion: reduce) {
  .ethereal-bg__shape { animation: none; }
}