@-webkit-keyframes scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-250px * 21));' 42/2 = nombre d'images
  }
}

@keyframes scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-250px * 21));' 42/2 = nombre d'images
  }
}
.slider {
  background-color: #dae0ec;'background: white;
  box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.125);
  height: 100px;
  margin-top: 650px;
  overflow: hidden;
  position: relative;
  width: 780px;
}
.slider::before, .slider::after {
  background: linear-gradient(to right, white 0%, rgba(255, 255, 255, 0) 0%);' augmenter le pourcentage pour un effet de rotation
  content: "";
  height: 100px;
  position: absolute;
  width: 780px;
  z-index: 2;
}
.slider::after {
  right: 0;
  top: 0;
  transform: rotateZ(180deg);
}
.slider::before {
  left: 0;
  top: 0;
}
.slider .slide-track {
  -webkit-animation: scroll 60s linear infinite;'temps defilement
          animation: scroll 60s linear infinite;
  display: flex;
  width: calc(250px * 20);'espace entre image
}
.slider .slide {
  height: 100px;
  width: 250px;
}