body {
	width: 800px; height: 100vh;
	box-sizing: border-box;
	margin: auto; padding: 2em;
	border: 1px solid silver;
	border-top: 0; border-bottom: 0;
}

#grid {
	border-collapse: collapse;
	border: 2px solid silver;
}
#grid td {
	width: 24px; height: 24px;
	border: 1px solid silver;
}
#grid td.alive {
	background-color: silver;
}

#ctrl {
	float: right;
	width: 200px;
}
#ctrl button{
	padding: .8em 2em;
	margin-bottom: .8em;
}