<div class='target'></div>
$unit: 1em;

.target {
	margin: 3*$unit;
	border: solid 2*$unit transparent;
	padding: 4*$unit;
	width: 2*$unit; height: 2*$unit;
	border-radius: 50%;
	box-shadow: 0 0 0 2*$unit #000, 
		inset 0 0 0 2*$unit #000;
	background: #000 content-box;
}
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