@mixin responsive($screen-size) {
	// 480
		@if $screen-size == xs {
			@media only screen and (min-width: $screen-xs) {
				@content;
			}
		}
	// 768
		@else if $screen-size == sm {
			@media only screen and (min-width: $screen-sm) {
				@content;
			}
		}
	// 992
		@else if $screen-size == md {
			@media only screen and (min-width: $screen-md) {
				@content;
			}
		}
	// 1440
		@else if $screen-size == lg {
			@media only screen and (min-width: $screen-lg) {
				@content;
			}
		}
	// customised break point
		@else {
			@media only screen and ($screen-size) {
				@content;
			}
		}
}