sass-ified example of styles

_content.scss

// base styles for the content container div
.content {
	width: 100%;
	margin: 0;
	padding: 0 1.25em 1.25em 1.25em;
	background-color: #fff;
	float: left;
}

// break at 31.25em, builds on the base
@media screen and (min-width: $tnybreak) {

	.content {
		padding: 0 2.5em 1.25em 2.5em;
	}

}

// break at 52.5em, builds on the base & $tnybreak
@media screen and (min-width: $smlbreak) {

	.content {
		width: 70%;
	}

}