expected - CSS

$l-device: 1200px;$m-device: 760px;
$s-device: 480px;

@mixin d($size) {
@if $size == l {
@media screen and (min-width: $l-device) {
@content;
}
}
@else if $size == m {
@media screen and (min-width: $m-device) and (max-width: $l-device - 1) {
@content;
}
}
@else if $size == s {
@media screen and (max-width: $s-device - 1) {
@content;
}
}
}