Use .drop and .inner as a ShadowStyle
Daily Coding Tip 139
ShadowStyle isn’t used with the regular .shadow modifier. That modifier can be called on any type that conforms to the View protocol, but ShadowStyle only exists within a function of ShapeStyle.
In other words, any ShapeStyle can be modified with the .shadow function, which takes a ShadowStyle of .inner or .drop.
