style.css

* {
	padding: 0;
	margin: 0;
	box-sizing: border-box;
}

body {
	width: 100%;
	height: 100vh;
	display: flex;
	justify-content: center;
	align-items: center;
	flex-direction: column;
	font-family: Poppins, sans-serif;
	font-size: 16px;
}

.title {
	padding: 20px;
	font-size: 5em;
	font-weight: 500;
}

.title sub {
	font-size: 0.4em;
	font-weight: 300;
}

.switch {
	display: flex;
	justify-content: center;
	align-items: center;
}

.switch .radio-check {
	display: flex;
	justify-content: center;
	align-items: center;
	padding: 15px;
	font-size: 1.3em;
	font-weight: 300;
}

.switch label {
	order: 2;
	margin: 5px;
}

input#in {
	padding: 5px;
	border: 1px solid #000;
	border-radius: 5px;
	font-size: 1.2em;
	outline: none;
	width: 30%;
}

input[type='number']::-webkit-inner-spin-button,
input[type='number']::-webkit-outer-spin-button {
	-webkit-appearance: none;
	-moz-appearance: none;
	appearance: none;
	margin: 0;
}

.output {
	display: flex;
	padding: 20px;
	font-size: 25px;
	height: 40px;
}

.output:empty {
	display: block;
}