material
fun materialPlaceholderTheme(color: Color = MaterialTheme.colorScheme.surfaceVariant, highlightColor: Color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.3f), shape: Shape = RectangleShape): PlaceholderTheme
Builds a PlaceholderTheme derived from the current MaterialTheme.
Background uses MaterialTheme.colorScheme.surfaceVariant and the default highlight is a Shimmer colored with MaterialTheme.colorScheme.onSurface at 30% opacity, so placeholders track the active light/dark color scheme automatically.