flutter gradient border
final kInnerDecoration = BoxDecoration(
color: Colors.white,
border: Border.all(color: Colors.white),
borderRadius: BorderRadius.circular(32),
);
final kGradientBoxDecoration = BoxDecoration(
gradient: LinearGradient(colors: [Colors.black, Colors.redAccent]),
border: Border.all(
color: kHintColor,
),
borderRadius: BorderRadius.circular(32),
);