@mixin bp($point) {
  @if $point == small {
    @media screen and (min-width: 600px) { @content; }
  }
  @else if $point == medium {
    @media screen and (min-width: 900px) { @content; }
  }
  @else {
    @media screen and (min-width: $point) { @content; }
  }
}