@mixin square($size) {
    width: $size;
    height: $size;
}

@mixin aspect-ratio($value) {
    @if type-of($value) != "number" {
        @error "The value parameter must be of type 'number'.";
    }

    padding-bottom: #{100 * $value}#{"%"};
    width: 100%;
    height: 0;
}