.cgs-slider {position: relative; overflow: hidden;}
.cgs-slide {position: absolute; width: 100%; opacity: 0; transition: opacity .5s;}
.cgs-slide:first-child {opacity: 1;}
.cgs-prev, .cgs-next {
  position: absolute; top: 50%; transform: translateY(-50%);
  background: rgba(0,0,0,.5); color: #fff; border: none; padding: 10px; cursor: pointer;
}
.cgs-prev {left: 10px;} .cgs-next {right: 10px;}