woocommerce/packages/woocommerce-blocks/assets/js/base/components/checkbox-control/style.scss

.wc-block-components-checkbox {
	@include reset-typography();
	align-items: flex-start;
	display: flex;
	position: relative;
	margin-top: em($gap-large);

	.wc-block-components-checkbox__input[type="checkbox"] {
		font-size: 1em;
		appearance: none;
		border: 2px solid $input-border-gray;
		border-radius: 2px;
		box-sizing: border-box;
		height: em(24px);
		width: em(24px);
		margin: 0;
		min-height: 24px;
		min-width: 24px;
		overflow: hidden;
		position: static;
		vertical-align: middle;
		background-color: #fff;

		&:checked {
			background: #fff;
			border-color: $input-border-gray;
		}

		&:focus {
			outline: 2px solid $input-border-gray;
			outline-offset: 2px;
		}

		&::before,
		&::after {
			content: "";
		}

		&:not(:checked) + .wc-block-components-checkbox__mark {
			display: none;
		}

		.has-dark-controls & {
			border-color: $controls-border-dark;
			background-color: $input-background-dark;

			&:checked {
				background: $input-background-dark;
				border-color: $controls-border-dark;
			}

			&:focus {
				outline: 2px solid $controls-border-dark;
				outline-offset: 2px;
			}
		}
	}

	&.has-error {
		color: $alert-red;

		a {
			color: $alert-red;
		}
		.wc-block-components-checkbox__input {
			&,
			&:hover,
			&:focus,
			&:active {
				border-color: $alert-red;
			}
			&:focus {
				outline: 2px solid $alert-red;
				outline-offset: 2px;
			}
		}
	}

	.wc-block-components-checkbox__mark {
		fill: #000;
		position: absolute;
		margin-left: em(3px);
		margin-top: em(1px);
		width: em(18px);
		height: em(18px);

		.has-dark-controls & {
			fill: #fff;
		}
	}

	> span,
	.wc-block-components-checkbox__label {
		padding-left: $gap;
		vertical-align: middle;
		line-height: em(24px);
	}
}

// Hack to hide the check mark in IE11
// See comment: https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/2320/#issuecomment-621936576
@include ie11() {
	.wc-block-components-checkbox__mark {
		display: none;
	}
}

.theme-twentytwentyone {
	.wc-block-components-checkbox__input[type="checkbox"],
	.has-dark-controls .wc-block-components-checkbox__input[type="checkbox"] {
		background-color: #fff;
		border-color: var(--form--border-color);
		position: relative;
	}

	.wc-block-components-checkbox__input[type="checkbox"]:checked,
	.has-dark-controls
	.wc-block-components-checkbox__input[type="checkbox"]:checked {
		background-color: #fff;
		border-color: var(--form--border-color);
	}

	.wc-block-components-checkbox__mark {
		display: none;
	}
}