pre[data-number] {
	position: relative;
	padding: 1em 0 1em 3em;
}

.line-number {
	position: absolute;
	left: 0;
	right: 0;
	padding: inherit 0;
	margin-top: 1em; /* Same as .prism's padding-top */

	background: transparent;
	
	pointer-events: none;
	
	line-height: inherit;
	white-space: pre;
}

	.line-number:before,
	.line-number[data-end]:after {
		content: attr(data-start);
		position: absolute;
		top: .4em;
		left: .6em;
		min-width: 1em;
		padding: 0 .5em;
		color: #999;
		font: bold 65%/1.5 sans-serif;
		text-align: center;
		vertical-align: .3em;
		border-radius: 999px;
		text-shadow: none;
		border: 0;
	}
	
	.line-number[data-end]:after {
		content: attr(data-end);
		top: auto;
		bottom: .4em;
	}