@-webkit-keyframes scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-250px * 14));
  }
}

@keyframes scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-250px * 14));
  }
}
.slider {
  background: white;
  <!-- box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.125); -->
  height: 300px;
  margin: auto;
  overflow: hidden;
  position: relative;
  <!-- width: 900px; -->
}



@media screen and (min-width: 800px) {
  	div.slider {
    		width: 900px;
		height: 300px;
 		 }
	}

@media screen and (max-width: 800px) {
  	div.slider {
		width: 260px;
		height: 310px;
  		}
	}



.slider::before, .slider::after {
  <!-- background: linear-gradient(to right, white 0%, rgba(255, 255, 255, 0) 100%);  -->
  content: "";
  height: 100px;
  position: absolute;
  width: 200px;
  z-index: 2;
}
.slider::after {
  right: 0;
  top: 0;
  transform: rotateZ(180deg);
}
.slider::before {
  left: 0;
  top: 0;
}
.slider .slide-track {
  -webkit-animation: scroll 70s linear infinite;
          animation: scroll 70s linear infinite;
  display: flex;
  width: calc(250px * 22);
}
.slider .slide {
  height: 100px;
  width: 250px;
}