Calculator.css

*,*::before,*::after{
	box-sizing: border-box;
	font-family: sans-serif;
	font-weight:normal;
}

body {
	padding: 0;
	margin:0;
    background:linear-gradient(to right, #00AAFF,purple);
}


.calculator-grid {
	display: grid;
	justify-content: center;
	align-content: center;
	min-height: 100vh;
	grid-template-columns: repeat(4, 100px);
	grid-template-rows: minmax(120px,auto) repeat(5,100px);
}

.calculator-grid > button {
	cursor: pointer;
	font-size: 3rem;
	border: 1px solid white;
	outline: none;
	background-color: rgba(255,255,255,.75);

}

.calculator-grid > button:hover {
	background-color: rgba(255,255,255,.9);
}

.span-two {
	grid-column: span 2;
}

.output {
	grid-column: 1/-1;
	background-color: rgba(0,0,0,.75);
	display: flex;
	align-items: flex-end;
	justify-content: space-around;
	flex-direction: column;
	padding: 10px;
	word-wrap: break-word;
	word-break: break-all;
}

.output .previous-operand {
	color:rgba(255,255,255,.75);
	font-size: 1.5rem;
}

.output .current-operand {
	color:white;
	font-size: 2.5rem;
}