style.css

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

.container {
	width: 100vw;
	height: 100vh;
	background: rgb(78, 140, 165);
}

.container input {
	width: 49%;
	color: black;
}

.container__input-wrap {
	width: 400px;
}

.container__action-wrap {
	width: 400px;
}

#plus {
	display: inline-block;
	width: 49%;
	height: 15px;
	background: rgb(57, 197, 92);
	border: 1px solid rgb(0, 255, 149);
	border-radius: 15px;
	color: black;
}

#plus:active {
	transition: all .035s;
	transform: translateY(1px);
}

#minus {
	display: inline-block;
	width: 50%;
	height: 15px;
	background: rgb(197, 57, 57);
	border: 1px solid rgb(255, 0, 0);
	border-radius: 15px;
	color: black;
}

#minus:active {
	transition: all .035s;
	transform: translateY(1px);
}

#multiply {
	display: inline-block;
	width: 49%;
	height: 15px;
	background: rgb(57, 141, 197);
	border: 1px solid rgb(0, 110, 255);
	border-radius: 15px;
	color: black;
}

#multiply:active {
	transition: all .035s;
	transform: translateY(1px);
}

#divide {
	display: inline-block;
	width: 50%;
	height: 15px;
	background: rgb(197, 132, 57);
	border: 1px solid rgb(255, 174, 0);
	border-radius: 15px;
	color: black;
}

#divide:active {
	transition: all .035s;
	transform: translateY(1px);
}

#submit {
	color: black;
	width: inherit;
	margin-bottom: 5px;
}

#result {
	text-align: center;
	padding-top: 15px;
	color: green;
}

.result {
	width: inherit;
	height: 60px;
	background: rgb(151, 221, 118);
	border-radius: 20px;
}

.remainder {
	display: none;
	text-align: center;
	margin: 5px;
	font-size: 10px;
	opacity: .45;
}