.button-cta {
    width:70px;
    height:70px;

    background-image: url("../imgs/whats_icon.png");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    border: none;
    cursor: pointer;
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 1000;
}