Syntax

@media [not] _media-type_ and (_media-feature: value_) and (_media-feature: value_) {
	/* CSS rules to apply */
}

Examples

/* Apply different rules for small screens */
@media (max-width: 600px) {
	/* CSS rules */
}

The above will only apply to screens slimmer than 600px, but you can also create a middle filter.

@media (max-width: 600px) and (min-width: 500px) {
	/* CSS Rules */*
}

This will only apply for screens between 500px and 600px wide.

References