body {
	width: 90%;
	max-width: 800px;
	margin: 0 auto;
	font-family: Arial, sans-serif;
}

@media (min-width: 640px) {
	body {
		background-color: #eaf6ff;
	}
}

h1 {
	font-size: 2rem;
}

@media (max-width: 499px) {
	h1 {
		font-size: 1.5rem;
	}
}

@media (min-width: 641px) {
	h1 {
		font-size: 2.5rem;
	}
}

#fixed-size-grid-items ul {
	list-style: none;
	padding-left: 0;
	display: flex;
	flex-wrap: wrap;
}

#fixed-size-grid-items aside {
	width: 170px;
	margin: 10px;
	font-size: 0.8rem;
	padding: 10px;
	box-sizing: border-box;
}

#stretchable-grid-items ul {
	list-style: none;
	padding-left: 0;
	margin: 1rem -10px;
	display: flex;
	flex-wrap: wrap;
}

#stretchable-grid-items li {
	width: 100%;
}

#stretchable-grid-items aside {
	margin: 10px;
	padding: 10px;
	box-sizing: border-box;
}

@media (min-width: 480px) {
	#stretchable-grid-items li {
		width: 50%;
	}
}

@media (min-width: 640px) {
	#stretchable-grid-items li {
		width: 25%;
	}
}