Jetpack compose alpha background animated

backgroundAlphaAnimated.kt

@Composable
fun BackgroundAlphaAnimated() {
    val animatedAlpha = remember { Animatable(0f) }
    Box(
        Modifier
            .background(color = (Color.DarkGray.copy(alpha = animatedAlpha.value)))
            .fillMaxSize()

    )
    LaunchedEffect(animatedAlpha) {
        animatedAlpha.animateTo(
            targetValue = 1f,
            animationSpec = infiniteRepeatable(tween(4000), RepeatMode.Reverse)
        )
    }
}