body {
counter-reset: item-counter;
}
.item {
counter-increment: item-counter;
}
.item:before {
content: counter(item-counter, upper-roman) ". "; /* by specifying the upper-roman as style the output would be in roman numbers */
}
<div class='item'>Item No: 1</div>
<div class='item'>Item No: 2</div>
<div class='item'>Item No: 3</div>
In the above example, the counter's output would be displayed as I, II, III (roman numbers) instead of the usual 1, 2, 3 as the developer has explicitly specified the counter's style.