BoxShadowValue object is taken by the boxShadow style prop. It is comprised of 2-4 lengths, an optional color, and an optional inset boolean. These values collectively define the box shadow’s color, position, size, and blurriness.
Example
Keys and values
offsetX
The offset on the x-axis. This can be positive or negative. A positive value indicates right and negative indicates left.
offsetY
The offset on the y-axis. This can be positive or negative. A positive value indicates up and negative indicates down.
blurRadius
Represents the radius used in the Gaussian blur algorithm. The larger the value the blurrier the shadow is. Only non-negative values are valid. The default is 0.
spreadDistance
How much larger or smaller the shadow grows or shrinks. A positive value will grow the shadow, a negative value will shrink the shadow.
color
The color of the shadow. The default is black.

