woocommerce/plugins/woocommerce-blocks/packages/components/totals-wrapper/style.scss

.wc-block-components-totals-wrapper {
	border-top: 1px solid $universal-border-light;
	padding: $gap 0;

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

	&.has-bottom-border {
		&::after {
			border-bottom-width: 1px;
		}
	}
	// TotalWrappers like Discount and Fee are sometimes empty
	// this prevents displaying the empty areas in Order Summary
	&:empty {
		padding: 0;
		border-width: 0;
		&::after {
			content: none;
		}
	}

	&.slot-wrapper {
		padding: 0;

		> * > * {
			padding: $gap 0;

			// Removes the border for the slot inserted
			&::after {
				border-width: 0;
			}
		}
	}
}

.wc-block-components-discounts-meta {
	.wc-block-components-totals-wrapper {
		&:first-child {
			border-top: 1px solid $universal-border-light;

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