SOURCE

<div></div>

html,body { /*这里没用*/
                width: 100%;
                height: 100%;
                margin: 0;
                padding: 0;
            }
div {
    width: 100px;
    height: 100px;
    text-decoration: none;
    margin: 15px;
    border-radius: 10px;
    padding: 10px 20px;
    box-shadow: 2px 2px 4px gray;
    background-color: white;
    color: slategrey;
    text-shadow: 1px 1px 1px gray;
    margin: 0 auto;
    position: relative;
    top: 50%;
    margin-top: -60px;
}

div:hover {
    box-shadow: 0px 0px 0px rgba(0, 0, 0, 0.2), 0px 0px 0px rgba(255, 255, 255, 0.8), inset 18px 18px 30px rgba(0, 0, 0, 0.1), inset -18px -18px 30px rgba(255, 255, 255, 1);
    transition: box-shadow .2s ease-out;
    text-shadow: 1px 2px 2px gray;
}