((s) => {
	s = document.createElement('style');
	s.textContent = `
li[data-open="0"] ul {
	display:none;
}
li[data-open="0"] {
	filter:brightness(0.7) hue-rotate(45deg);
	font-weight: 700;
	list-style-type: disc!important;
}
	`;
	document.head.append(s);
	document.querySelector('#toc')
	.querySelectorAll('ul')
	.forEach((u) => {
		const p = u.parentElement;
		if (p.tagName !== 'LI')
			return;
		if (p.dataset.open == "1")
			return;
		p.dataset.open = 1;
		let a = document.createElement('a');
		a.textContent = " \u25BC ";
		a.href = "javascript:;";
		p.insertBefore(a, p.firstChild);
		a.addEventListener('click', (e) => {
			e = e.target;
			let l = e.closest('li');
			if ( l ) {
				let x = l.dataset;
				if (x.open == "1") {
					x.open = 0;
					e.textContent = " \u25B6 ";
				} else {
					x.open = 1;
					e.textContent = " \u25BC ";
				}
			}
		}, false);
	});
})();