* {
	box-sizing: border-box;
	margin: 0;
	padding: 0;
  }
  
  body {
	background-color: #222;
	color: #fff;
	font-family: sans-serif;
  }
  
  .calculator {
	background-color: #444;
	border-radius: 20px;
	box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
	margin: 50px auto;
	overflow: hidden;
	padding: 20px;
	width: 400px;
  }
  
  .display {
	border-bottom: 2px solid #666;
	margin-bottom: 20px;
	padding: 10px;
	text-align: right;
  }
  
  .display input {
	background-color: transparent;
	border: none;
	color: #fff;
	font-size: 40px;
	height: 80px;
	text-align: right;
	width: 100%;
  }
  
  .buttons {
	display: grid;
	grid-gap: 5px;
	grid-template-columns: repeat(4, 1fr);
  }
  
  button {
	background-color: #222;
	border: none;
	color: #fff;
	cursor: pointer;
	font-size: 30px;
	padding: 20px;
	transition: background-color 0.2s ease;
  }
  
  button:hover {
	background-color: #111;
  }
  
  .operator {
	background-color: #ca5502;
	font-size: 40px;
  }
  
  .equals {
	background-color: #2196f3;
	grid-column: span 2;
	font-size: 40px;
  }
  
  .clear {
	background-color: #cc0000;
	font-size: 20px;
  }
  
  .backspace {
	background-color: #4caf50;
	font-size: 20px;
  }