metabuilder/scss/components/Skeleton.module.scss

// Skeleton Component - Material Design 3
// ======================================
// Loading placeholder with shimmer animation using M3 tokens

@keyframes skeleton-shimmer {
  0% {
    background-position: -200px 0;
  }
  100% {
    background-position: calc(200px + 100%) 0;
  }
}

.fakemui-skeleton {
  display: inline-block;
  background-color: var(--mat-sys-surface-container-highest);
  background-image: linear-gradient(
    90deg,
    transparent 0%,
    color-mix(in srgb, var(--mat-sys-on-surface) 8%, transparent) 50%,
    transparent 100%
  );
  background-size: 200px 100%;
  background-repeat: no-repeat;
  animation: skeleton-shimmer 1.5s ease-in-out infinite;

  // Variants
  &--text {
    height: 1em;
    border-radius: var(--mat-sys-corner-extra-small);
    transform: scale(1, 0.6);
    transform-origin: 0 60%;

    &:empty::before {
      content: '\00a0'; // Non-breaking space for height
    }
  }

  &--rectangular {
    border-radius: var(--mat-sys-corner-extra-small);
  }

  &--circular {
    border-radius: var(--mat-sys-corner-full);
  }

  &--rounded {
    border-radius: var(--mat-sys-corner-medium);
  }

  // Wave animation variant
  &--wave {
    animation: none;
    overflow: hidden;
    position: relative;

    &::after {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      background: linear-gradient(
        90deg,
        transparent,
        color-mix(in srgb, var(--mat-sys-on-surface) 8%, transparent),
        transparent
      );
      animation: skeleton-shimmer 1.6s linear 0.5s infinite;
    }
  }

  // Pulse animation variant
  &--pulse {
    animation: skeleton-pulse 1.5s ease-in-out 0.5s infinite;
  }
}

@keyframes skeleton-pulse {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0.4;
  }
  100% {
    opacity: 1;
  }
}