style.css

@import url('https://fonts.googleapis.com/css2?family=Lato:ital,wght@0,100;0,300;0,400;0,700;0,900;1,100;1,300;1,400;1,700;1,900&display=swap');

html {
	height: 100%;
}

body {
	display: flex;
	height: 100%;

	align-items: center;
	justify-content: center;
}

.display {
	display: flex;
	flex-wrap: nowrap;
	font-family: 'Lato', sans-serif;
	font-weight: 500;
	font-style: normal;
	font-size: 70px;

	min-height: 84px;

	border-style: solid;
	border-width: 1px;
	border-color: black;

	justify-content: end;
}

.break {
	flex-basis: 100%;
	height: 0;
}

div {
	display: flex;
	flex: 1 1 auto;
	justify-content: center;
}

.container {
	display: flex;
	flex-grow: 1;
	min-height: 105px;
	align-self: stretch;
}

button:not(.zero) {
	width: 100%;
	height: 100%;

	font-family: 'Lato', sans-serif;
	font-weight: 500;
	font-style: normal;
	font-size: 50px;

	border: 1px;
	border-color: black;
	border-style: solid;
}

.calculator {
	display: flex;
	flex-wrap: wrap;
	min-height: 534px;
	max-width: 426px;
	align-items: center;

	background-color: black;
}

.zero {
	flex-basis: 212%;
	font-family: 'Lato', sans-serif;
	font-weight: 500;
	font-style: normal;
	font-size: 50px;

	border: 1px;
	border-color: black;
	border-style: solid;
}

#ac {
	background-color: red;
}

.numbers {
	background-color: gray;
}

.operations {
	background-color: orange;
}

#equals {
	background-color: lightseagreen;
}

.display {
	background-color: lightgray;
}