styles.less

:root {
	--st-label-height: 2.5rem;
	--st-subnodes-padding-left: 1.5rem;
	--st-collapse-icon-height: var(--st-label-height);
	--st-collapse-icon-width: 1.25rem;
	--st-collapse-icon-size: 0.75rem;
}

sortable-tree-node {
	position: relative;
	z-index: 1;
	display: flex;
	flex-direction: column;

	& * {
		user-select: none;
	}

	& > :first-child {
		display: flex;
		align-items: center;
		height: var(--st-label-height);
	}

	& > :nth-child(2) {
		display: none;
		flex-direction: column;
		padding-left: var(--st-subnodes-padding-left);
	}

	&[open] > div:nth-child(2) {
		display: flex;
	}

	& > :nth-child(3) {
		position: absolute;
		display: flex;
		align-items: center;
		top: 0;
		left: ~'calc(var(--st-collapse-icon-width) * -1)';
		height: var(--st-collapse-icon-height);
		font-size: var(--st-collapse-icon-size);
		cursor: pointer;
	}

	& > :nth-child(2):empty + span {
		display: none;
	}
}