Media query exmaple.

gistfile1.css

.article {
	/* styles used regardless of window size */
}

@media all and (min-width: 320px) {
	.article {
		width: 100px;
		height: 100px;
	}
}
@media all and (min-width: 500px) {
	.article {
		width: 150px;
		height: 150px;
	}
}
@media all and (min-width: 700px) {
	.article {
		width: 200px;
		height: 200px;
	}
}
@media all and (min-width: 900px) {
	.article {
		width: 250px;
		height: 250px;
	}
}
@media all and (min-width: 1100px) {
	.article {
		width: 300px;
		height: 300px;
	}
}