body{
	font-family: 'Open Sans',sans-serif;
    background: rgba(79, 218, 223, 0.181);
}
h2{
    color: #000000;
    text-align: center;
    font-size: 30px;
    padding-bottom: 30px;
    text-decoration: underline;
}
#container{
	width: 1000px;
	height: 550px;
	margin: 20px auto;	
}
#calculator{
	width: 320px;
	height: 520px;
	background-color: #000000;
	margin: 0 auto;
	top: 20px;
	position: relative;
	border-radius: 5px;
	color: #ffffff;
	box-shadow: 0 15px 20px 10px rgba(86, 248, 32, 0.344), 0 15px 20px 0 rgba(86, 248, 32, 0.344);
}
#result{
	height: 120px;
}
#history{
	text-align: right;
	height: 20px;
	margin: 0 20px;
	font-size: 25px;
	color: #ffffff;
	padding-top: .5px;
	padding-bottom: 1px;
}
#output{
	text-align: right;
	height: 60px;
	margin: 10px 20px;
	font-size: 35px;
	color: #ffffff;
}
#keyboard{
	height: 400px;
}
.operator, .number, .empty{
	width: 60px;
	height: 60px;
	margin: 10px;
	float: left;
	border-radius: 50%;
	border-width: 0;
	font-weight: bold;
	font-size: 25px;
	margin-bottom: 10px;
}
.number, .empty{
	background-color: #363535;
}
.number, .operator{
	cursor: pointer;
}
.operator:active, .number:active{
	font-size: 16px;
}
.operator:focus, .number:focus, .empty:focus{
	outline: 0;
}
button:nth-child(1){
    color: red;
	background-color: #313131;
}
button:nth-child(2),
button:nth-child(3){
	background-color: #313131;
	
    color: #12d900;
}
button:nth-child(4),
button:nth-child(8),
button:nth-child(12),
button:nth-child(16){
	font-size: 30px;
	background-color: #313131;
    color: #12d900;
}

button:nth-child(20){
    font-size: 30px;
	background-color: #67cf00;
    color: #ffffff;
}
button:nth-child(5),
button:nth-child(6),
button:nth-child(7),
button:nth-child(9),
button:nth-child(10),
button:nth-child(11),
button:nth-child(13),
button:nth-child(14),
button:nth-child(15),
button:nth-child(17),
button:nth-child(18),
button:nth-child(19){
    font-size: 22px;
	background-color: #313131;
    color: #ffffff;
}