Demo

style.css
setup.css
index.html

section:hover {
	background-color: aquamarine;
	transform: scale(105%);
}

section:nth-child(2) {
	transition-duration: 2s, 1s;
	transition-property: background-color, transform;
	transition-timing-function: linear, ease-in-out;
	will-change: transform; /* Improves the scaling performance! */
}

body {
	--base: 20px;

	display: grid;
	font-family: 'Helvetica', sans-serif;
	gap: var(--base);
	padding: var(--base);
}

section {
	background-color: gold;
	padding: calc(var(--base) / 2);
}

h2 { font-size: calc(var(--base) * 3); }

<!DOCTYPE html>
<html>
	<head>
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<link href="/assets/styles/reset.css" rel="stylesheet">
		<link href="setup.css" rel="stylesheet">
		<link href="style.css" rel="stylesheet">
	</head>
	<body>
		<section>
			<p>This element has no transition.</p>
		</section>
		<section>
			<p>This element has a transition!</p>
		</section>
	</body>
</html>