shadow method
Implementation
ContainerBuilder shadow() => boxShadow([
BoxShadow(
color: Colors.black.withValues(alpha: 0.06),
blurRadius: 2,
offset: const Offset(0, 1),
),
BoxShadow(
color: Colors.black.withValues(alpha: 0.04),
blurRadius: 1,
offset: const Offset(0, 1),
spreadRadius: -0.5,
),
]);