body {
	background-color: #ccc;
}

.big-frame {
	/*border: 1px solid #000;*/
	width: 160px;
	/*font-size: 0;*/
	margin: 20% auto 0 auto;
}

.piece {
	width: 50px;
	height: 50px;
	/*background-color: #555;*/
	border: 1px solid #555;
	display: inline-block;
	box-sizing: border-box;
	cursor: pointer;
	vertical-align: top;
	/*margin-bottom: 4px;*/
}
.piece:hover {
	background-color: #aaa;
}

.piece[status="true"] {
	background: #555; 
}