CSS styles based on number of children

index.html

<div class="list">
	<div>Item 1</div>
	<div>Item 2</div>
	<div>Item 3</div>
	<div>Item 4</div>
	<div>Item 5</div>
</div>

<div class="list">
	<div>Item 1</div>
	<div>Item 2</div>
	<div>Item 3</div>
	<div>Item 4</div>
	<div>Item 5</div>
	<div>Item 6</div>
</div>

styles.css

/* less than 6 children = green */
.list > * {
	background: green;
}

/* 6+ children = orange */
.list > *:nth-last-child(n+6),
.list > *:nth-last-child(n+6) ~ * {
	background: orange;
}