body,
html {
	height: 100%;
	margin: 0;
	padding: 0;
	background-color: #aaa;
	display: grid;
	place-content: center;
}

/* game objects */

.start {
	background-color: #0f0;
	height: 20px;
	width: 20px;
	cursor: pointer;
}
.finish {
	background-color: #f00;
	height: 20px;
	width: 20px;
	cursor: pointer;
}
.path {
	background-color: #fff;
	height: 20px;
	width: 20px;
	cursor: crosshair;
}
.wall {
	background-color: #000;
	height: 20px;
	width: 20px;
	cursor: not-allowed;
}

.stage {
	display: grid;
	grid-template-columns: repeat(20, 1fr);
	grid-template-rows: repeat(20, 1fr);
	width: calc(20px * 20);
	height: calc(20px * 20);
}