.progress {
  height: 4px;
  max-width: 100%;
  min-width: 260px;
  position: relative;
  display: block;
  overflow: hidden;
  margin: 0 auto;
  .progress-bar {
    display: block;
    position: absolute;
    left: -200px;
    width: 200px;
    height: 4px;
    animation: loading 2s linear infinite;
    -webkit-animation: loading 2s linear infinite;
    -moz-animation: loading 2s linear infinite;
    -o-animation: loading 2s linear infinite;
    -ms-animation: loading 2s linear infinite;
  }
}
@keyframes loading {
  from {
    left: -200px;
    width: 30%;
  }
  50% {
    width: 30%;
  }
  70% {
    width: 70%;
  }
  80% {
    left: 50%;
  }
  95% {
    left: 120%;
  }
  to {
    left: 100%;
  }
}
@-webkit-keyframes loading {
  from {
    left: -200px;
    width: 30%;
  }
  50% {
    width: 30%;
  }
  70% {
    width: 70%;
  }
  80% {
    left: 50%;
  }
  95% {
    left: 120%;
  }
  to {
    left: 100%;
  }
}