tabler/scss/ui/_switch.scss

$custom-switch-width: 2.25rem;
$custom-switch-height: 1.25rem;
$custom-switch-padding: 1px;

.custom-switch {
  user-select: none;
  cursor: default;
  display: inline-flex;
  align-items: center;
  margin: 0;
}

.custom-switch-input {
  position: absolute;
  z-index: -1;
  opacity: 0;
}

.custom-switches-stacked {
  display: flex;
  flex-direction: column;

  .custom-switch {
    margin-bottom: .5rem;
  }
}

.custom-switch-indicator {
  display: inline-block;
  height: $custom-switch-height;
  width: $custom-switch-width;
  background: $gray-200;
  border-radius: 50px;
  position: relative;
  vertical-align: bottom;
  border: 1px solid $border-color;
  transition: .3s border-color, .3s background-color;

  &:before {
    content: '';
    position: absolute;
    height: calc(#{$custom-switch-height} - #{$custom-switch-padding * 2 + 2px});
    width: calc(#{$custom-switch-height} - #{$custom-switch-padding * 2 + 2px});
    top: $custom-switch-padding;
    left: $custom-switch-padding;
    background: #fff;
    border-radius: 50%;
    transition: .3s left;
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  }

  .custom-switch-input:checked ~ & {
    background: $primary;

    &:before {
      left: calc(#{$custom-switch-width - $custom-switch-height} + #{$custom-switch-padding})
    }
  }

  .custom-switch-input:focus ~ & {
    box-shadow: $input-btn-focus-box-shadow;
    border-color: $primary;
  }
}

.custom-switch-description {
  margin-left: .5rem;
  color: $text-muted;
  transition: .3s color;

  .custom-switch-input:checked ~ & {
    color: $body-color;
  }
}