BoxShadow

Container(
  padding: EdgeInsets.all(20),
  decoration: BoxDecoration(
      borderRadius: BorderRadius.circular(20),
      color: Colors.white,
      boxShadow: [
        BoxShadow(
          offset: Offset(0, 4),
          blurRadius: 30,
          color: kShadowColor,
        )
      ]),
)

boxShadow: [
  BoxShadow(
    offset: Offset(0, 10),
    blurRadius: 22,
    color: kPrimaryColor.withOpacity(0.22),
  ),
  BoxShadow(
    offset: Offset(-15, -15),
    blurRadius: 20,
    color: Colors.white,
  )
]