elevation function
Implementation
List<BoxShadow> elevation(Color col, int elevation) {
return [
BoxShadow(color: col.withOpacity(0.6), offset: Offset(0.0, 4.0), blurRadius: 3.0 * elevation, spreadRadius: -1.0 * elevation),
BoxShadow(color: col.withOpacity(0.44), offset: Offset(0.0, 1.0), blurRadius: 2.2 * elevation, spreadRadius: 1.5),
BoxShadow(color: col.withOpacity(0.12), offset: Offset(0.0, 1.0), blurRadius: 4.6 * elevation, spreadRadius: 0.0),
];
}