SASS: @mixin respond-to

_respond-to.scss

@mixin respond-to($val, $query){
  @media ($val : $query){
    @content
  }
}

// Usage
.example{
  @include respond-to(min-width, 900px){
    float: none;
    width: 100%;
  }
}

// Return
@media (min-width: 900px){
  .example{
    float: none;
    width: 100%;
  }
}