@mixin screen($point) {
    @if $point == xl {
        @media screen and (min-width: 1280px) { @content ; }
    }
    @else if $point == lg {
        @media (min-width: 1024px) { @content ; }
    }
    @else if $point == md {
        @media (min-width: 768px) { @content ; }
    }
    @else if $point == sm {
        @media (min-width: 640px)  { @content ; }
    }
}