style.css

header {
	display: block;
	margin: 0 auto;
	width: 100%;
	text-align: center;
}

header h1 {
	font-family: Arial;
	font-size: 60px;
	font-weight: bold;
	margin: 0 auto;
}

header #new_game_button {
	display: block;
	margin: 0px auto;
	width: 100px;
	padding: 10px 10px;
	background-color: #8f7a66;
	font-family: Arial;
	color: white;
	border-radius: 10px;
	text-decoration: none;
}

header #new_game_button:hover {
	background-color: #9f8b77;
}

header p {
	font-family: Arial;
	font-size: 25px;
	margin: 5px auto;
}

#grid_container {
	width: 460px;
	height: 460px;
	padding: 20px;
	margin: 0px auto;
	background-color: #bbada0;
	border-radius: 10px;
	position: relative;
}

.grid_cell {
	width: 100px;
	height: 100px;
	border-radius: 6px;
	background-color: #ccc0b3;
	position: absolute;
}

.number_cell {
	border-radius: 6px;
	font-family: Arial;
	font-weight: bold;
	font-size: 60px;
	line-height: 100px;
	text-align: center;
	position: absolute;
}