<!doctype html>
<html>
	<head>
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<link href="/assets/reset.css" rel="stylesheet">
		<link href="setup.css" rel="stylesheet">
		<link href="style.css" rel="stylesheet">
	</head>
	<body>
		<ol>
			<li>
				<p>Item 1</p>
			</li>
			<li>
				<p>Item 2</p>
			</li>
			<li>
				<p>Item 3</p>
			</li>
		</ol>
		<ol>
			<li>
				<p>Item 1</p>
			</li>
			<li>
				<p>Item 2</p>
			</li>
			<li>
				<p>Item 3</p>
			</li>
		</ol>
		<ol>
			<li>
				<p>Item 1</p>
			</li>
			<li>
				<p>Item 2</p>
			</li>
			<li>
				<p>Item 3</p>
			</li>
		</ol>
		<ol>
			<li>
				<p>Item 1</p>
			</li>
			<li>
				<p>Item 2</p>
			</li>
			<li>
				<p>Item 3</p>
			</li>
		</ol>
		<ol>
			<li>
				<p>Item 1</p>
			</li>
			<li>
				<p>Item 2</p>
			</li>
			<li>
				<p>Item 3</p>
			</li>
		</ol>
	</body>
</html>
index.html
			body {
	font-family: sans-serif;
	padding: 1rem;
}

ol { background-color: gold; }

ol:not(:first-child) { margin-block-start: 1rem; }

li {
	background-color: tomato;
	border-block-end: 0.1rem solid firebrick;
	border-inline-end: 0.1rem solid firebrick;
	padding: 0.5rem;
}
setup.css
			ol {
	block-size: 9rem;
	display: flex;
}

/* All grow equally. */
ol:nth-child(2) li { flex-grow: 1; }

ol:nth-child(3) li:nth-child(1) {
	background-color: hotpink;
	flex-grow: 1; /* Just grow this one. */
}

ol:nth-child(4) li:nth-child(1) {
	background-color: hotpink;
	flex-grow: 1;
}

ol:nth-child(4) li:nth-child(2) {
	background-color: crimson;
	flex-grow: 2; /* Grow twice as much. */
}

ol:nth-child(5) li { inline-size: 50%; } /* With 3 `li` would be 150%. */

ol:nth-child(5) li:nth-child(1) {
	background-color: lightsalmon;
	flex-shrink: 0; /* Don’t shrink this one! */
}
style.css