wagtail/client/scss/components/_switch.scss

@use 'sass:math';

$switch-width: 40px;
$switch-height: 20px;
$switch-border: 2px;
$switch-outline: 3px;

$switch-border-radius: math.div(($switch-height + $switch-border * 2), 2);
$switch-outline-radius: $switch-border-radius + $switch-outline;

// All the greys in Wagtail are really dark or really bright
$switch-color-middle-grey: #777;

.switch {
  display: inline-flex;
  align-items: center;
  margin: 5px 0;

  // Disable forms styling that's applied to the <label> tag
  width: unset;
  float: unset;

  &__toggle {
    position: relative;
    cursor: pointer;

    &::before,
    &::after {
      content: '';
      transition: all 100ms cubic-bezier(0.4, 0, 0.2, 1);
      display: block;
    }

    &::before {
      height: $switch-height;
      width: $switch-width;
      border-radius: $switch-border-radius;
      background: $switch-color-middle-grey;
      border: $switch-border solid $switch-color-middle-grey;
    }

    &::after {
      box-sizing: border-box;
      position: absolute;
      top: 50%;
      transform: translate($switch-border, -50%);
      height: $switch-height;
      width: $switch-height;
      border: $switch-border solid $color-white;
      border-radius: 50%;
      background-color: $color-white;
    }
  }

  [type='checkbox']:checked + &__toggle::before {
    background: $color-teal;
    border-color: $color-teal;
  }

  [type='checkbox']:checked + &__toggle::after {
    transform: translate(
      calc(#{$switch-width} + #{$switch-border} - 100%),
      -50%
    );
  }

  [type='checkbox']:disabled + &__toggle {
    cursor: not-allowed;
    filter: grayscale(100%);
    opacity: 0.3;
  }

  [type='checkbox']:disabled + &__toggle::after {
    opacity: 0.5;
    box-shadow: none;
  }

  [type='checkbox']:focus + &__toggle {
    outline: $color-focus-outline solid $switch-outline;
  }

  [type='checkbox'] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
  }

  // Colour changes for when displaying on teal background
  &--teal-background {
    $background: #03b0b1;

    .switch__toggle {
      &::before {
        background-color: #b9b9b9;
        border: $switch-border solid #b9b9b9;
        opacity: 0.6;
      }

      &::after {
        background-color: $color-white;
      }
    }

    [type='checkbox']:checked + .switch__toggle::before {
      // Override the white-background styling
      background-color: $background;
      border-color: $background;
      opacity: 1;
    }
  }
}