<div class='box'></div>

.box {
	--r: 50px;
	margin: .75em auto 0;
	outline: solid 4px #b53;
	width: calc(100% - 2*var(--r) - 2em);
	max-width: 47em;
	min-height: 8em;
	background: radial-gradient(circle at 0 0, #000 var(--r), transparent 0)
}