woocommerce/plugins/woocommerce-blocks/assets/js/blocks/checkout/inner-blocks/checkout-fields-block/style.scss

.wc-block-checkout__form {
	margin: 0;
	max-width: 100%;
}
.is-mobile,
.is-small,
.is-medium {
	.wc-block-checkout__main {
		order: 1;
	}
}
.is-small,
.is-medium,
.is-large {
	.wc-block-checkout__shipping-fields,
	.wc-block-checkout__billing-fields {
		.wc-block-components-address-form {
			display: flex;
			flex-wrap: wrap;
			justify-content: space-between;
			gap: 0 calc(#{$gap-smaller} * 2); // Required for spacing especially when using flex-grow

			.wc-block-components-text-input,
			.wc-block-components-state-input,
			.wc-block-components-select-input {
				flex: 1 0 calc(50% - #{$gap-smaller}); // "flex-grow = 1" allows the input to grow to fill the space
				box-sizing: border-box;

				&:nth-of-type(2),
				&:first-of-type {
					margin-top: 0;
				}
			}

			.wc-block-components-address-form__company,
			.wc-block-components-address-form__address_1,
			.wc-block-components-address-form__address_2,
			.wc-block-components-country-input,
			.wc-block-components-checkbox {
				flex: 0 0 100%;
			}
		}
	}
}