Flexslider CSS - shadow over images - how?

Please use below CSS code for shadow over images:

/* Image box shadow */
.flexslider .slides > li {
  position: relative;
  z-index: 1;
}
.flexslider .slides > li::before {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 2;
  height: 100%;
  width: 100%;
  content: '';
  -webkit-box-shadow: 0 0 100px 30px rgba(0, 0, 0, 1) inset;
     -moz-box-shadow: 0 0 100px 30px rgba(0, 0, 0, 1) inset;
             box-shadow: 0 0 100px 30px rgba(0, 0, 0, 1) inset;
}
/* End */

Let me know incase of any query/concern regarding the same.

Thanks!