.bg-mask {
  perspective: 150px;
  -webkit-mask-image: linear-gradient(to top, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0));
          mask-image: linear-gradient(to top, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0));
  -webkit-mask-size: 100% 100%;
          mask-size: 100% 100%;
  -webkit-mask-repeat: no-repeat;
          mask-repeat: no-repeat;
  -webkit-mask-position: left top, left bottom;
          mask-position: left top, left bottom;
}