none | numeric values + (inset)
Block and Inline Elements
Defines one or more shadows for a box that can be either inside or outside. Multiple shadows are separated by commas. The four parameters that are used to define the shadow are (from first to last): horizontal distance, vertical distance, blur size, shadow size. Note that the shadow is cut around the element box, so an outer shadow is not visible "behind" an element if it has a transparent background!