node_modules/bulma/sass/elements/progress.sass

$progress-bar-background-color: $border !default
$progress-value-background-color: $text !default
$progress-border-radius: $radius-rounded !default

$progress-indeterminate-duration: 1.5s !default

.progress
  @extend %block
  -moz-appearance: none
  -webkit-appearance: none
  border: none
  border-radius: $progress-border-radius
  display: block
  height: $size-normal
  overflow: hidden
  padding: 0
  width: 100%
  &::-webkit-progress-bar
    background-color: $progress-bar-background-color
  &::-webkit-progress-value
    background-color: $progress-value-background-color
  &::-moz-progress-bar
    background-color: $progress-value-background-color
  &::-ms-fill
    background-color: $progress-value-background-color
    border: none
  // Colors
  @each $name, $pair in $colors
    $color: nth($pair, 1)
    &.is-#{$name}
      &::-webkit-progress-value
        background-color: $color
      &::-moz-progress-bar
        background-color: $color
      &::-ms-fill
        background-color: $color
      &:indeterminate
        background-image: linear-gradient(to right, $color 30%, $progress-bar-background-color 30%)

  &:indeterminate
    animation-duration: $progress-indeterminate-duration
    animation-iteration-count: infinite
    animation-name: moveIndeterminate
    animation-timing-function: linear
    background-color: $progress-bar-background-color
    background-image: linear-gradient(to right, $text 30%, $progress-bar-background-color 30%)
    background-position: top left
    background-repeat: no-repeat
    background-size: 150% 150%
    &::-webkit-progress-bar
      background-color: transparent
    &::-moz-progress-bar
      background-color: transparent

  // Sizes
  &.is-small
    height: $size-small
  &.is-medium
    height: $size-medium
  &.is-large
    height: $size-large

@keyframes moveIndeterminate
  from
    background-position: 200% 0
  to
    background-position: -200% 0