<!-- 
   add this code in <head></head> section <link href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"> 
  -->


<div class="box">
    <button><i class="fa fa-search"></i></button>
    <button><i class="fa fa-user"></i></button>
    <button><i class="fa fa-th-list"></i></button>
    <button><i class="fa fa-search"></i></button>
    <button><i class="fa fa-user"></i></button>
    <button><i class="fa fa-th-list"></i></button>
    <button><i class="fa fa-search"></i></button>
    <button><i class="fa fa-user"></i></button>
    <button><i class="fa fa-th-list"></i></button>
  </div>
  
*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body{
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #ebecf0;
  height: 100vh;
}
.box{
  width: 270px;
  text-align: center;
  padding: 32px;
}
.box button{
  width: 48px;
  height: 48px;
  color: #61677c;
  box-shadow: -5px -5px 20px #ffffff,
              5px 5px 20px #babecc;
  border: none;
  outline: none;
  padding: 16px;
  background: #ebecf0;
  border-radius: 8px;
  cursor: pointer;
  margin: 8px;
  display: inline-flex;
  justify-content: center;
  align-items: center;    
  font-size: 19px;
  transition: all 0.2s ease-in-out;      
}
.box button:hover{
  box-shadow: -2px -2px 5px #fff,
              2px 2px 5px #babecc;
}
.box button:active{
  box-shadow: inset -1px -1px 2px #babecc,
              inset -1px -1px 2px #fff;
}

External CSS

  1. https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.