.wpwtestimonial {
    position: relative;
    z-index: 1;
}

.wpwtestimonial .carousel-control-prev,
.wpwtestimonial .carousel-control-next,
.wpwtestimonial .carousel-indicators {
    z-index: 3;
}

.wpwtestimonial .mask {
    z-index: 2;
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
}

.wpwtestimonial .mask > img {
    width: 100%;
}