If the shadow is inset or drop, or a reference of a boolean token.
The horizontal offset of the shadow in pixels, or a reference to a number token.
The vertical offset of the shadow in pixels, or a reference to a number token.
The spread distance of the shadow in pixels, or a reference to a number token.
The amount of blur to apply to the shadow, or a reference to a number token.
The color as a string (e.g. "#FF5733"), or a reference to a color token.