@function rem($px, $base-font-size: 32px) {
  @if (unitless($px)) {
    @warn "Assuming #{$px} to be in pixels, attempting to convert it into pixels for you";
    @return rem($px + 0px); // That may fail.
  } @else if (unit($px) == em) {
    @return $px;
  }
  @return ($px / $base-font-size) * 1rem;
}