Useless condition

[KittyGiraudel]

@if variable-exists('ext-options') {
  $ext-opt: map-merge($ext-opt, $ext-options) !global;
}

Since you define $ext-options on top of the file and there is no way in Sass to unset a variable, this condition will always be met.

A more appropriate check would be:

@if type-of($ext-options) == 'map' {
  $ext-opt: map-merge($ext-opt, $ext-options) !global;
}

If you agree, I can submit a PR.

[jaicab]

This if statement was inherited from an older version of the plugin which didn't have any defaults. All very true, fixed on #8.