deemixer/public/css/progressbar.css

.progress {
  position: relative;
  height: 4px;
  display: block;
  width: 100%;
  background-color: var(--secondary-background);
  border-radius: 2px;
  margin: 0.5rem 0 1rem 0;
  overflow: hidden;
}

.progress .determinate {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  background-color: var(--accent-color);
  -webkit-transition: width .3s linear;
  transition: width .3s linear;
}

.progress .indeterminate {
  background-color: var(--accent-color);
}

.progress .indeterminate:before {
  content: '';
  position: absolute;
  background-color: inherit;
  top: 0;
  left: 0;
  bottom: 0;
  will-change: left, right;
  -webkit-animation: indeterminate 2.1s cubic-bezier(0.65, 0.815, 0.735, 0.395) infinite;
          animation: indeterminate 2.1s cubic-bezier(0.65, 0.815, 0.735, 0.395) infinite;
}

.progress .indeterminate:after {
  content: '';
  position: absolute;
  background-color: inherit;
  top: 0;
  left: 0;
  bottom: 0;
  will-change: left, right;
  -webkit-animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite;
          animation: indeterminate-short 2.1s cubic-bezier(0.165, 0.84, 0.44, 1) infinite;
  -webkit-animation-delay: 1.15s;
          animation-delay: 1.15s;
}

@-webkit-keyframes indeterminate {
  0% {
    left: -35%;
    right: 100%;
  }
  60% {
    left: 100%;
    right: -90%;
  }
  100% {
    left: 100%;
    right: -90%;
  }
}

@keyframes indeterminate {
  0% {
    left: -35%;
    right: 100%;
  }
  60% {
    left: 100%;
    right: -90%;
  }
  100% {
    left: 100%;
    right: -90%;
  }
}

@-webkit-keyframes indeterminate-short {
  0% {
    left: -200%;
    right: 100%;
  }
  60% {
    left: 107%;
    right: -8%;
  }
  100% {
    left: 107%;
    right: -8%;
  }
}

@keyframes indeterminate-short {
  0% {
    left: -200%;
    right: 100%;
  }
  60% {
    left: 107%;
    right: -8%;
  }
  100% {
    left: 107%;
    right: -8%;
  }
}