zotero/scss/components/_collection-tree.scss

#zotero-collections-tree-container {
	height: 5.2em;
}

#zotero-collections-tree {
	width: 100%;

	.virtualized-table {
		overflow-y: auto;
		flex: 1 0;
		text-overflow: ellipsis;
	}

	.cell.primary {
		display: flex;
		align-items: center;

		:not(.cell-text) {
			flex-shrink: 0
		}

		.cell-text {
			flex-shrink: 1;
			text-overflow: ellipsis;
			overflow: hidden;
			margin-left: 6px;
		}

		input.cell-text {
			border: 1px highlight solid;
			padding: 1px 2px;
			margin-right: 5px;
			width: 100%;
			font-size: inherit;
		}

		.cell-icon {
			min-width: 16px;
		}
	}

	.row.editing .cell {
		pointer-events: auto;
	}
}