.contents-tree {
	ul {
		border-left: 2px solid var(--global_color-foreground);
		list-style-type: none;
		padding-left: 1rem;
	}
	li summary {
		position: relative;
		&::before {
			content: '―';
			font-family: var(--font-serif-mono);
			position: absolute;
			left: -1rem;
		}
		&::marker {
			font-family: var(--font-serif-mono);
			content: '[+] ';
		}
		&:hover {
			cursor: pointer;
			& > span {
				text-decoration: underline;
			}
		} 
	}
	details[open] > summary::marker {
		content: '[-] ';
	}
}