options.css

:root {
	font: message-box;
	color: #333;
}
body {
	display: flex;
	flex-direction: column;
}
h1,
h2 {
	font-weight: 400;
}
h1 {
	font-size: 1.8rem;
	margin: 3rem 0 2rem;
	padding: 0 2ex;
}
h2 {
	font-size: 1.5rem;
	line-height: 1.25em;
	margin: 3rem 0 1rem;
	padding: 0 1ex;
	border: solid #aaa;
	border-width: 0 0 1px;
}
div {
	position: relative;
	margin: 0.5rem 0;
}
label,
legend {
	font-size: 1.25rem;
	line-height: 1.875rem;
}
legend {
	left: 8ex;
	padding: 0 1ex;
	border: none;
	font-weight: bold;
}
input[type='checkbox'] {
	display: none;
}
input ~ label {
	margin-left: 2.3rem;
}
p {
	margin: 0.5em 0 1em 2.3rem;
	color: #444;
}
input[type='checkbox'] ~ label::before {
	position: absolute;
	top: 0.075rem;
	left: 0;
	content: '';
	display: inline-block;
	width: 1.5rem;
	height: 1.5rem;
	border: 1px solid #888;
	border-radius: 2px;
	background: #ddd;
}
input[type='checkbox']:checked ~ label::before {
	background: #48c;
}
input[type='checkbox']:checked ~ .marker::before {
	pointer-events: none;
	position: absolute;
	content: '';
	top: 0.15rem;
	left: 0.5rem;
	width: 0.4rem;
	height: 0.95rem;
	display: block;
	border: solid white;
	border-width: 0 3px 3px 0;
	transform: rotate(45deg);
	z-index: 1;
}