.promo-box {
    border:none;
}

    .promo-box .mud-icon-root {
        width: 50%;
        height: 50%;
        border-radius: 50%;
        padding: 1.5rem;
        background: #ffd800;
        /* inner + outer shadow */
        box-shadow: rgba(0,0,0,0.4) -1px -1px 5px inset, /* inner shadow */
                    rgba(0,0,0,0.4) 2px 2px 10px; /* outer shadow */
    }