index.css

#panel {
	/*box-sizing: border-box;*/
	margin: auto;
  width: 220px;
  height: 320px;
  padding: 25px;    
  border: 1px solid #607d8b;
  border-radius: 5px;
}

#displayCalc{
	font-family: 'Exo', sans-serif;
	margin: auto;
	/*padding: 10px;*/
	height: 25px;
	width: 200px;
		border-radius: 5px 5px 0 0;

	border-top: 1px solid #607d8b;
	border-left: 1px solid #607d8b;
	border-right: 1px solid #607d8b;
	text-align: right;
	background-color: #cedeeb;
}

#displayAns{
	font-family: 'Exo', sans-serif;
	margin: auto;
	border-radius: 0 0 5px 5px;
	width: 200px;
	height: 25px;
	border-bottom: 1px solid #607d8b;
	border-left: 1px solid #607d8b;
	border-right: 1px solid #607d8b;
	text-align: right;
	background-color: #cedeeb;
}

#buttons {

	font-family: 'Supermercado One', cursive;
	font-size: 30px;
	width: 200px;
	margin: 0 auto;
	
	padding: 10px;
	height: 200px;
	width: 200px;
	/*border: 1px solid grey;*/
}

#buttons li {
	    
	border-radius: 5px;
	float: left;
		/*width: 33.3%;*/
	list-style: none;
	text-align: center;
	width: 20px;
  height: 20px;
  margin: 0 auto;
  padding: 14px;
	border:1px solid #607d8b;
}
	
.buttons li.first {
		clear:left;
}

.digit {
		background-color: #8080804d;

}
.operator {
	background-color: #03a9f480;
}