body{
    font-family: 'Opens Sans',sans-serif;
    background-color: black;
    
}
#container{
    width: 1000px;
    height: 550px;
    background-color: grey;
    margin: 20px auto;
}
#calculator{
    width: 320px;
    height: 520px;
    background: #ffffff;
    margin:0 auto;
    top: 20px;
    position: relative;
    border-radius: 5px;
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
}
#result{
    height: 120px;
}
#history{
    text-align: right;
    height: 20px;
    margin: 0 20px;
    padding-top: 20px;
    font-size: 15px;
    color: #919191;
}
#output{
    text-align: right;
    height: 60px;
    margin: 10px 20px;
    font-size: 30px;
    color: black;
}

#output-text{
	width: 250px;
	height: 120px;
	float: left;
}
#microphone{
	height: 30px;
	width: 30px;
	float: right;
	background-image: url(mic.png);
	background-size: 100% 100%;
    border: 1rem black;
	border-radius: 50%;
	margin: 20px;
	margin-top: 45px;
}
.record{	
	animation: microphone-animation 1.5s infinite;
}
@keyframes microphone-animation{
	0%{
		transform: scale(0.9);
	}
	70%{
		transform: scale(1);
		box-shadow: 0 0 0 10px rgba(0,148,255,0.4);
		
	}
	100%{
		transform: scale(0.9);
		box-shadow: 0 0 0 0 rgba(0,148,255,0);
	}
}
.tooltip{
	width: 200px;
	font-size: 9px;
	position: absolute;
	background-color: #dddddd;
	color: #636363;
	padding: 10px;
	top: 45px;
	transform: translateX(50px);
	border-radius: 5px;
	visibility: hidden;
}
.tooltip::before{
	content: '';
	position: absolute;
	border-width: 5px;
	border-style: solid;
	border-color:transparent #dddddd transparent transparent;
	left: 0;
	margin-left: -10px;
}
#output-microphone:hover .tooltip{
	visibility: visible;
}

#keyboard{
    height:400px;
}
.operator, .number, .empty{
    width: 50px;
    height: 50px;
    margin:15px;
    float: left;
    border-radius: 50%;
    border-width: 0;
    font-weight: bold;
    font-size: 15px;
}
.number{
    background-color: grey;
}
.empty{
    background-color: #eaedef;
}
.number, .operator{
    cursor: pointer;
}
.operator:active, .number:active{
    font-size: 13px;
}
.operator:focus, .number:focus, .empty:focus{
    outline: 1;
}
button:nth-child(1){
    background-color: grey;
}
button:nth-child(2){
    background-color:grey;
}
button:nth-child(3){
    background-color:grey;
}
button:nth-child(4){
    font-size: 20px;
    background-color: grey;
}
button:nth-child(8){
    font-size: 20px;
    background-color: grey;
}
button:nth-child(12){
    font-size: 20px;
    background-color: grey;
}
button:nth-child(16){
    font-size: 20px;
    background-color: #7d93e8;
}
button:nth-child(20){
    font-size: 20px;
    background-color: #9477af;
}