<style type = "text/css">
	body {

	}
	div {
		border: 1px grey solid;
	}
	.container {
		width: 1100px;
		min-height: 1000px;
		margin: 10px auto;
	}
	/*21 x 20*/
	.next-line {
		clear: both;
		width: 0;
		height: 0;
		border: 0;
	}
	.black {
		background-color: black;
	}
	.orange {
		background-color: orange;
	}
	.red {
		background-color: red;
	}
	.yellow {
		background-color: yellow;
	}
	.level {
		display: block;
	}
	.square {
		display: inline-block;
		width: 50px;
		height: 50px;
	}

	</style>