.button {
    height: 100px;
    width: 100px;
    position: relative;
    margin: 50px;
    color: white;
    text-align: center;
    line-height: 100px;

    /*закругленные углы и тень*/
    border-radius: 100px;
    box-shadow: 2px 2px 4px rgba(0,0,0,0.4);

    /*градиент*/
    background: #e51d16; /* fallback */
    background: linear-gradient(top, #e51d16 0%,#b21203 100%); /* W3C */
}

.button:before {
    content: '';
    width: 120px;
    height: 120px;
    display: block;
    z-index: -1;
    position: absolute;
    padding: 1rem;
    background: #ddd;
    left: -10px;
    top: -10px;
    border-radius: 100px;
    box-shadow: inset 2px 2px 4px rgba(0,0,0,0.4);
}

.button:after {
    content: '';
    width: 140px;
    height: 140px;
    display: block;
    z-index: -2;
    padding: 25px;
    background: #eee;
    position: absolute;
    left: -20px;
    top: -20px;
    border-radius: 100px;
    box-shadow: inset 2px 2px 4px rgba(0,0,0,0.4);
}