<div class="progress"></div>

.progress {
  width:120px;
  height:20px;
  border-radius: 20px;
  background:
   linear-gradient(orange 0 0) 0/0% no-repeat
   lightblue;
  animation:p 2s infinite steps(10);
}
@keyframes p {
    100% {background-size:110%}
}