body {
	width: 90%;
	max-width: 800px;
	margin-left: auto;
	margin-right: auto;
}

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

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

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

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

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

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

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

@media (min-width: 481px) {
	#stretchable-grid-items li {
		width: 50%;
	}
}

@media (min-width: 641px) {
	#stretchable-grid-items li {
		width: 25%;
	}
}

#stretchable-grid-items aside {
	margin: 10px;
}