Bootstrap/scss/_progress.scss

//
// Progress animations
//

@keyframes progress-bar-stripes {
  from { background-position: $spacer-y 0; }
  to { background-position: 0 0; }
}


//
// Basic progress bar
//

.progress {
  display: block;
  width: 100%;
  height: $spacer-y; // todo: make a new var for this
  margin-bottom: $spacer-y;
}
.progress[value] {
  // Set overall background
  background-color: $progress-bg;
  // Remove Firefox and Opera border
  border: 0;
  // Reset the default appearance
  appearance: none;
  // Set overall border radius
  @include border-radius($progress-border-radius);
}

// Filled-in portion of the bar
.progress[value]::-ms-fill {
  background-color: $progress-bar-color;
  // Remove right-hand border of value bar from IE10+/Edge
  border: 0;
}
.progress[value]::-moz-progress-bar {
  background-color: $progress-bar-color;
  @include border-left-radius($progress-border-radius);
}
.progress[value]::-webkit-progress-value {
  background-color: $progress-bar-color;
  @include border-left-radius($progress-border-radius);
}
// Tweaks for full progress bar
.progress[value="100"]::-moz-progress-bar {
  @include border-right-radius($progress-border-radius);
}
.progress[value="100"]::-webkit-progress-value {
  @include border-right-radius($progress-border-radius);
}

// Unfilled portion of the bar
.progress[value]::-webkit-progress-bar {
  background-color: $progress-bg;
  @include border-radius($progress-border-radius);
  @include box-shadow($progress-box-shadow);
}
base::-moz-progress-bar, // Absurd-but-syntactically-valid selector to make these styles Firefox-only
.progress[value] {
  background-color: $progress-bg;
  @include border-radius($progress-border-radius);
  @include box-shadow($progress-box-shadow);
}

// IE9 hacks to accompany custom markup. We don't need to scope this via media queries, but I feel better doing it anyway.
@media screen and (min-width:0\0) {
  .progress {
    background-color: $progress-bg;
    @include border-radius($progress-border-radius);
    @include box-shadow($progress-box-shadow);
  }
  .progress-bar {
    display: inline-block;
    height: $spacer-y;
    text-indent: -999rem; // Simulate hiding of value as in native `<progress>`
    background-color: $progress-bar-color;
    @include border-left-radius($progress-border-radius);
  }
  .progress[width="100%"] {
    @include border-right-radius($progress-border-radius);
  }
}


//
// Striped
//

.progress-striped[value]::-webkit-progress-value {
  @include gradient-striped();
  background-size: $spacer-y $spacer-y;
}
.progress-striped[value]::-moz-progress-bar {
  @include gradient-striped();
  background-size: $spacer-y $spacer-y;
}
.progress-striped[value]::-ms-fill {
  @include gradient-striped();
  background-size: $spacer-y $spacer-y;
}
// IE9
@media screen and (min-width:0\0) {
  .progress-bar-striped {
    @include gradient-striped();
    background-size: $spacer-y $spacer-y;
  }
}


//
// Animated
//

.progress-animated[value]::-webkit-progress-value {
  animation: progress-bar-stripes 2s linear infinite;
}
.progress-animated[value]::-moz-progress-bar {
  animation: progress-bar-stripes 2s linear infinite;
}
// IE9
@media screen and (min-width:0\0) {
  .progress-animated .progress-bar-striped {
    animation: progress-bar-stripes 2s linear infinite;
  }
}


//
// Variations
//

.progress-success {
  @include progress-variant($progress-bar-success-bg);
}
.progress-info {
  @include progress-variant($progress-bar-info-bg);
}
.progress-warning {
  @include progress-variant($progress-bar-warning-bg);
}
.progress-danger {
  @include progress-variant($progress-bar-danger-bg);
}