/// Convert from base 2 to base 10
/// @access private
/// @param {Number} $value - binary to convert
/// @return {Number}
@function binary-to-decimal($value) {
  $value: $value + unquote('');
  $result: if(str-slice($value, 1, 1) == "0", 0, 1);

  @for $i from 2 through str-length($value) {
    $c: str-slice($value, $i, $i);

    @if not index("0" "1", $c) {
      @error "Not binary.";
    }

    $result: $result * 2;

    @if $c == "1" {
      $result: $result + 1;
    }
  }

  @return $result;
}