themes-wordpress/varia/sass/blocks/group/_editor.scss

.wp-block-group {
	&.has-background {
		padding: #{ 0.666 * map-deep-get($config-global, "spacing", "vertical") };

		@include media(mobile) {
			padding: #{map-deep-get($config-global, "spacing", "vertical")};
		}
	}
}

.wp-block[data-type="core/group"] > .editor-block-list__block-edit > div > .wp-block-group.has-background > .wp-block-group__inner-container > .editor-inner-blocks > .editor-block-list__layout > .wp-block[data-align=full] {
	margin: 0;
	width: 100%;
}