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

Code Example 1

/* Keyword values */
box-shadow: none;

/* offset-x | offset-y | color */
box-shadow: 60px -16px teal;

/* offset-x | offset-y | blur-radius | color */
box-shadow: 10px 5px 5px black;

/* offset-x | offset-y | blur-radius | spread-radius | color */
box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.2);

/* inset | offset-x | offset-y | color */
box-shadow: inset 5em 1em gold;

/* Any number of shadows, separated by commas */
box-shadow: 3px 3px red, -1em 0 0.4em olive;

/* Global keywords */
box-shadow: inherit;
box-shadow: initial;
box-shadow: unset;

Code Example 2

Source:www.w3schools.com
0
image shadow cssCSS By Ankur on May 1 2020 Donate
<!Doctype>
<html>
<head>
  <style>
    .img {
      width: 400px;
      height: 200px;
      border:2px solid #fff;
      background: url(img/tiger.png) no-repeat;
      box-shadow: 10px 10px 5px #ccc;
      -moz-box-shadow: 10px 10px 5px #ccc;
      -webkit-box-shadow: 10px 10px 5px #ccc;
      -khtml-box-shadow: 10px 10px 5px #ccc;
    }
  </style>
</head>
<body>
  <div class="img"></div>
</body>
</html>

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); 
}

Code Example 4

<!Doctype>
<html>
<head>
  <style>
    .img {
      width: 400px;
      height: 200px;
      border:2px solid #fff;
      background: url(img/tiger.png) no-repeat;
      box-shadow: 10px 10px 5px #ccc;
      -moz-box-shadow: 10px 10px 5px #ccc;
      -webkit-box-shadow: 10px 10px 5px #ccc;
      -khtml-box-shadow: 10px 10px 5px #ccc;
    }
  </style>
</head>
<body>
  <div class="img"></div>
</body>
</html>

Code Example 5

box-shadow: 0 0 10px;

Code Example 6

#Box-shadow-example {
Box-shadow:0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
}
<!-- offset-x, offset-y, (blur-radius and/or spread-radius=optional) and color-->

Learn ReactJs, React Native from akashmittal.com