woocommerce/plugins/woocommerce-blocks/assets/js/base/components/sidebar-layout/style.scss

.wc-block-sidebar-layout {
	display: flex;
	flex-wrap: wrap;
	margin: 0 (-$gap) $gap;

	.wc-block-main {
		margin: 0;
		padding: 0 $gap;
		width: 65%;
	}
}

.wc-block-sidebar {
	margin: 0;
	padding: 0 $gap;
	width: 35%;

	// Reset Gutenberg <Panel> styles when used in the sidebar.
	.components-panel__body {
		border-top: 1px solid $core-grey-light-600;
		border-bottom: 1px solid $core-grey-light-600;

		&.is-opened {
			padding-left: 0;
			padding-right: 0;

			> .components-panel__body-title {
				margin-left: 0;
				margin-right: 0;
			}
		}

		> .components-panel__body-title,
		.components-panel__body-toggle {
			&,
			&:hover,
			&:focus,
			&:active {
				background-color: transparent;
				color: inherit;
			}
		}

		.components-panel__body-toggle {
			font-weight: normal;
			font-size: inherit;
			padding-left: 0;
			padding-right: 36px;

			&.components-button,
			&.components-button:focus:not(:disabled):not([aria-disabled="true"]) {
				color: inherit;
			}
		}
	}
}

@include breakpoint( "<782px" ) {
	.wc-block-sidebar-layout {
		flex-direction: column;
		margin: 0 0 $gap;

		.wc-block-main {
			padding: 0;
			width: 100%;
		}
		.wc-block-sidebar {
			padding: 0;
			width: 100%;

			// Reset (remove) totals "card" styling on mobile.
			.components-card {
				box-shadow: none;
				border: none;
			}
			.components-card__body {
				border: none;
				padding: 0;
			}
		}
	}
}