signal-desktop/stylesheets/_progress.scss

@keyframes progress-bar-stripes {
  from {
    background-position: 40px 0;
  }
  to {
    background-position: 0 0;
  }
}
.progress-bar-striped {
  background-image: -webkit-linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.75) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.75) 50%,
    rgba(255, 255, 255, 0.75) 75%,
    transparent 75%,
    transparent
  );
  background-image: -o-linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.75) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.75) 50%,
    rgba(255, 255, 255, 0.75) 75%,
    transparent 75%,
    transparent
  );
  background-image: linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.75) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.75) 50%,
    rgba(255, 255, 255, 0.75) 75%,
    transparent 75%,
    transparent
  );
  -webkit-background-size: 40px 40px;
  background-size: 40px 40px;
}
.progress-bar-striped {
  background-image: -webkit-linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.75) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.75) 50%,
    rgba(255, 255, 255, 0.75) 75%,
    transparent 75%,
    transparent
  );
  background-image: -o-linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.75) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.75) 50%,
    rgba(255, 255, 255, 0.75) 75%,
    transparent 75%,
    transparent
  );
  background-image: linear-gradient(
    45deg,
    rgba(255, 255, 255, 0.75) 25%,
    transparent 25%,
    transparent 50%,
    rgba(255, 255, 255, 0.75) 50%,
    rgba(255, 255, 255, 0.75) 75%,
    transparent 75%,
    transparent
  );
}
.progress-bar.active {
  -webkit-animation: progress-bar-stripes 2s linear infinite;
  -o-animation: progress-bar-stripes 2s linear infinite;
  animation: progress-bar-stripes 2s linear infinite;
}

.bar-container {
  background: $blue_l;

  .progress-bar {
    height: 100%;
  }
}