Check out example codes for "css shadow generator". It will help you in understanding the concepts better.

Code Example 1

box-shadow: 3px 3px 6px 5px #ccc;

or

box-shadow: 0px 5px 17px -7px rgba(0, 0, 0, 0.75);

Code Example 2

shadowColor: "#000",
shadowOffset: {
	width: 0,
	height: 2,
},
shadowOpacity: 0.25,
shadowRadius: 3.84,

elevation: 5,

Code Example 3

.element {
    /* https://developer.mozilla.org/en-US/docs/Web/CSS/box-shadow  */
  
 	/* offset-x | offset-y | blur-radius | spread-radius | color */
 	-webkit-box-shadow: 0px -1px 30px -2px rgba(0,0,0,0.75);
	-moz-box-shadow: 0px -1px 30px -2px rgba(0,0,0,0.75);
	box-shadow: 0px -1px 30px -2px rgba(0,0,0,0.75); 
}

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