a { color: green; }

/* :focus is triggered always. */
a:focus { outline: none; }

/* :focus-visible will only trigger on keyboard tab through */
a:focus-visible { 
  outline: 0.1rem solid currentColor;
  outline-offset: 0.2rem;
  border-radius: 0.1rem;
}
<!DOCTYPE html>
<html>
	<head>
		<title>Pseudo-focus</title>
		<link href="style.css" rel="stylesheet">
	</head>
	<body>
		<p>This is a paragraph with <a href="#">a link</a> in it.</p>
		<p>And another one with <a href="/topic/css">another link</a>.</p>
	</body>
</html>