styles.css

html,body {
	margin:0; 
	padding:0; 
	width:100%; 
	height:100%;
	background:#111;
}

.top {
	position:absolute;
	margin:auto;
	top:0px;
	bottom:0px;
	left:0px;
	right:0px;
	width:800px;
	height:480px;
}
.top textarea {
	width:800px;
	height:480px;
	background:#000;
	border:0px none;
	color:#d80;
	font:15px monospace;
}
.top textarea:focus {
	outline-style: none;
}
.bottom {
	background:#000;
	position:absolute;
	height:30px;
	bottom:0px;
	left:0px;
	right:0px;
}
input[type='button'] {
	background:#020;
	color:#aa0;
	border:1px solid #090;
	margin-top:5px;
	margin-left:10px;
	cursor: pointer;
}
input[type='button']:hover {
	background:#000;
	border:1px solid #5f5;
}
input[type='button']:focus {
	outline-style: none;
}
.output {
	position:absolute;
	margin:auto;
	top:0;
	bottom:0;
	left:0;
	right:0;
	width:650px;
	height:480px;
	z-index:10;
	border:1px solid #999;
}
.output > pre {
	overflow-y:auto;
	width:650px;
	height:480px;
	font:9px monospace;
	background:#444;
	color:#fa0;
	margin:0;
}
.output button {
	background:#222;
	border:1px solid #999;
	color:#fa0;
	border-radius:5px;
}