@-webkit-keyframes scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-250px * 7));
  }
}



.slider .slide-track {
  -webkit-animation: scroll 5s linear infinite;
          animation: scroll 4s linear infinite;
  display: flex;
  width: calc(250px * 14);
}
.slider .slide {
  height: 100px;
  width: 250px;
}