.wp-block-sd-image-bg-style figure.wp-block-image {
    position: relative;
}

.wp-block-sd-image-bg-style .wp-block-image figcaption {
    position: absolute;
    width: calc(100% - 0.66em);
    bottom: 0;
    text-align: center;
    margin: 0;
    bottom: 0;
    padding: .33em 0;
    z-index: 3;
}