src/librustdoc/html/static/css/settings.css

.setting-line {
	margin: 0.6em 0 0.6em 0.3em;
	position: relative;
}

.setting-line .choices {
	display: flex;
	flex-wrap: wrap;
}

.setting-line .radio-line input {
	margin-right: 0.3em;
	height: 1.2rem;
	width: 1.2rem;
	color: inherit;
	border: 1px solid currentColor;
	outline: none;
	-webkit-appearance: none;
	cursor: pointer;
	border-radius: 50%;
}
.setting-line .radio-line input + span {
	padding-bottom: 1px;
}

.radio-line .setting-name {
	width: 100%;
}

.radio-line .choice {
	margin-top: 0.1em;
	margin-bottom: 0.1em;
	min-width: 3.8em;
	padding: 0.3em;
	display: flex;
	align-items: center;
	cursor: pointer;
}
.radio-line .choice + .choice {
	margin-left: 0.5em;
}

.toggle {
	position: relative;
	width: 100%;
	margin-right: 20px;
	display: flex;
	align-items: center;
	cursor: pointer;
}

.toggle input {
	opacity: 0;
	position: absolute;
}

.slider {
	position: relative;
	width: 45px;
	min-width: 45px;
	display: block;
	height: 28px;
	margin-right: 20px;
	cursor: pointer;
	background-color: #ccc;
	transition: .3s;
}

.slider:before {
	position: absolute;
	content: "";
	height: 19px;
	width: 19px;
	left: 4px;
	bottom: 4px;
	transition: .3s;
}

input:checked + .slider:before {
	transform: translateX(19px);
}

.setting-line > .sub-settings {
	padding-left: 42px;
	width: 100%;
	display: block;
}

#settings .setting-line {
	margin: 1.2em 0.6em;
}

.setting-line .radio-line input:checked {
	box-shadow: inset 0 0 0 3px var(--main-background-color);
	background-color: var(--settings-input-color);
}
.setting-line .radio-line input:focus {
	box-shadow: 0 0 1px 1px var(--settings-input-color);
}
/* In here we combine both `:focus` and `:checked` properties. */
.setting-line .radio-line input:checked:focus {
	box-shadow: inset 0 0 0 3px var(--main-background-color),
		0 0 2px 2px var(--settings-input-color);
}
.setting-line .radio-line input:hover {
	border-color: var(--settings-input-color) !important;
}
input:checked + .slider {
	background-color: var(--settings-input-color);
}