body{
	margin: 0;
	height: 100vh;
	display: flex;
	align-items: center;
	justify-content: center;
	background: linear-gradient(lightyellow, tan);
}

#app {
    width: 66vw;
    display: flex;
    flex-direction: column;
    align-items: center;
    box-shadow: 0 1em 4em rgba(0, 0, 0, 0.5);
	border-radius: 2em;
	padding: 8em 5em;
    background: linear-gradient(black, dimgray, black);
    font-family: sans-serif;
    font-size: 1vw;
    user-select: none;
}

.choose-type input[name=arithmetic-type] {
	position: absolute;
	visibility: hidden;
}

.choose-type label {
    font-size: 2.5em;
    color: skyblue;
    margin: 0.3em;
	letter-spacing: 0.02em;
    position: relative;
    transition: 0.3s;
}

.choose-type label:not(:first-of-type)::before {
	content: '|';
	position: absolute;
	left: -0.5em;
	filter: opacity(0.6);
}

.choose-type label:hover {
	color: deepskyblue;
	cursor: pointer;
}

.choose-type input[name=arithmetic-type]:checked + label {
	text-transform: capitalize;
    color: deepskyblue;
	border-style: solid;
	border-width: 0 0 0.1em 0;
}

.score{
    font-size: 2em;
    color: silver;
    margin: 1em 0 2em 0;
    width: 45%;
	display: flex;
	justify-content: space-between;
}

.expression {
	font-size: 12em;
	display: flex;
	align-items: center;
}

.expression span {
	margin: 0 0.05em;
}

.expression .number{
	color: orange;
}

.expression .operation{
	color: skyblue;
}

.expression .result{
	color: gold;
}

.expression .show {
	color: skyblue;
	font-size: 0.8em;
	line-height: 1em;
	width: 1.5em;
	text-align: center;
}

.judgment {
	font-size: 8em;
	align-self: flex-end;
}

.judgment .right {
	color: lightgreen;
}

.judgment .wrong {
	color: orangered;
}

.button {
	background-color: #222;
	border: 1px solid #555;
	padding: 0.1em;
}

.button:hover {
	background-color: #333;
	cursor: pointer;
}

.button:active {
	background-color: #222;
}