Forum Moderators: not2easy
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Which CSS selector</title>
<style>
[for="married"] {
outline: 1px solid red;
}
</style>
</head>
<body>
<form>
<label for="name">Name</label>
<input type="text" id="name">
<label for="married">Married</label>
<input type="checkbox" id="married">
</form>
</body>
</html>