#calculator{
	background: #444444;
	width: 300px;height: 350px;
	padding: 15px;
	border-radius: 20px;
	margin: 20px auto;
}

#calculator #screen{
	display: inline-block;
	background: #5F5F5F; 
	color: #7E7E7E;
	text-align: right;
	width: 100%;
	border-radius: 10px 10px 0px 0px;
	font-family: 'Oswald', sans-serif;
	padding: 5px;
}
#calculator #screen span{
	display: inline-block;
	color: rgba(255,255,255,0.8);
}

#calculator #keyboard{
	display: grid;
	height: calc(100% - 34px);
	grid-template-columns: repeat(4, 1fr);
	grid-template-rows: repeat(5, 1fr);
	grid-gap: 1px;
	padding: 2px 0px;
}

/*Highlight disabled*/
#calculator .key button{
		-webkit-touch-callout: none; /* iOS Safari */
		-webkit-user-select: none; /* Safari */
		-khtml-user-select: none; /* Konqueror HTML */
		-moz-user-select: none; /* Firefox */
		-ms-user-select: none; /* Internet Explorer/Edge */
		user-select: none; /* Non-prefixed version, currently
		supported by Chrome and Opera */
}

#calculator .key button{
	/*border-radius: 15px;*/
	width: 100%; height: 100%;
	outline: none; border: none;
	color: #E0E0E0; background: #838383;
	font-size: 15px;
}

#calculator .key button:active{
	/*background: rgba(255,255,255,0.5);*/
	opacity: .7;
}

#calculator .key.zero{
	grid-column: 1 / 3;
}

#calculator .key:nth-child(-n+3) button{
	background: #555555;
}

#calculator .key:nth-child(4n) button, 
#calculator .key:nth-child(19) button{
	background: #FF8300;
}