.wcboost-variation-swatches-item.wcboost-variation-swatches-item--multi-color {
    position: relative;
    overflow: hidden;
}

.wcboost-variation-swatches-item.wcboost-variation-swatches-item--multi-color::before {
    content: '';
    position: absolute;
    top: 20%;
    left: 20%;
    width: 200%;
    height: 200%;
    background: var(--wcboost-swatches-color-secondary);
    transform: rotate(45deg);
}