da https://getbootstrap.com/docs/4.1/utilities/shadows/

.boxombra {
box-shadow:5px,5px,15px,-3px,#000000;
background:#F4F4F4;
-webkit-box-shadow: 5px,5px,15px,-3px,#000000;
-moz-box-shadow: 5px,5px,15px,-3px,#000000;}

css style