website/sass/_pico/components/_progress.scss

/**
 * Progress
 */

// Reboot based on :
// - normalize.css v8.0.1 | MIT License | github.com/necolas/normalize.css
// - sanitize.css v13.0.0 | CC0 1.0 Universal | github.com/csstools/sanitize.css
// ––––––––––––––––––––

// 1. Add the correct display in Edge 18- and IE
// 2. Add the correct vertical alignment in Chrome, Edge, and Firefox
progress {
  display: inline-block; // 1
  vertical-align: baseline; // 2
}

// Pico
// ––––––––––––––––––––

progress {
  // Reset the default appearance
  -webkit-appearance: none;
  -moz-appearance: none;

  // Styles
  display: inline-block;
  appearance: none;
  width: 100%;
  height: 0.5rem;
  margin-bottom: calc(var(--spacing) * 0.5);
  overflow: hidden;

  // Remove Firefox and Opera border
  border: 0;
  border-radius: var(--border-radius);
  background-color: var(--progress-background-color);

  // IE10 uses `color` to set the bar background-color
  color: var(--progress-color);

  &::-webkit-progress-bar {
    border-radius: var(--border-radius);
    background: none;
  }
  &[value]::-webkit-progress-value {
    background-color: var(--progress-color);
  }
  &::-moz-progress-bar {
    background-color: var(--progress-color);
  }

  // Indeterminate state
  @media (prefers-reduced-motion: no-preference) {
    &:indeterminate {
      background: var(--progress-background-color)
        linear-gradient(
          to right,
          var(--progress-color) 30%,
          var(--progress-background-color) 30%
        )
        top left / 150% 150% no-repeat;
      animation: progress-indeterminate  1s linear infinite;

      &[value]::-webkit-progress-value {
        background-color: transparent;
      }
      &::-moz-progress-bar {
        background-color: transparent;
      }
    }
  }
}

[dir="rtl"] {
  @media (prefers-reduced-motion: no-preference) {
    progress:indeterminate {
      animation-direction: reverse;
    }
  }
}

@keyframes progress-indeterminate {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}