wagtail/client/scss/components/forms/_switch.scss

@use 'sass:math';

$switch-width: 36px;
$switch-height: 18px;
$switch-border: 2px;
$switch-outline: 3px;

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

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

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

  &__icon {
    width: 12px;
    height: $switch-height;
    position: absolute;
    top: 50%;
    transform: translate(calc(var(--w-direction-factor) * 5px), -50%);
    color: theme('colors.text-button');

    @media (forced-colors: active) {
      color: SelectedItemText;
    }
  }

  &__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 + $switch-border * 2;
      width: $switch-width + $switch-border * 2;
      border-radius: $switch-border-radius;
      background: theme('colors.text-placeholder');
      border: $switch-border solid theme('colors.text-placeholder');
    }

    &::after {
      position: absolute;
      top: 50%;
      transform: translate(
        calc(var(--w-direction-factor) * $switch-border),
        -50%
      );
      height: $switch-height;
      width: $switch-height;
      border: $switch-border solid theme('colors.surface-page');
      border-radius: theme('borderRadius.full');
      background-color: theme('colors.surface-page');
    }
  }

  [type='checkbox']:checked + &__toggle::before {
    background: theme('colors.text-button-outline-default');
    border-color: theme('colors.text-button-outline-default');

    @media (forced-colors: active) {
      background: SelectedItem;
      border-color: SelectedItem;
    }
  }

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

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

  [type='checkbox']:focus-visible + &__toggle {
    outline: theme('colors.focus') solid $switch-outline;
  }

  @supports not selector(:focus-visible) {
    [type='checkbox']:focus + &__toggle {
      outline: theme('colors.focus') solid $switch-outline;
    }
  }

  [type='checkbox'] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
    width: 100%;
    height: 100%;
  }
}