div#board {
	width: 280px;
}

div#board div {
	width: 28px;
	height: 28px;
	float: left;
	border: 1px solid #fff;
}

div#board div.piece {
	background-color: #b00 !important;
}

div#board div.valid {
	background-color: #bbb;
}

div#board div.on {
	border: 1px solid #0f0;
	background-color: #0dd;
}