#outer-container {
  width: 100%;
  overflow: hidden;
}

#inner-container1 {
  display: flex;
  white-space: nowrap;
  animation: scrollLeft 50s linear infinite;
}

#outer-container:hover #inner-container {
  animation-play-state: paused;
}

.item {
  display: inline-block;
  width: auto;
  margin: 5px;
}

@keyframes scrollLeft {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-100%));
  }
}