ignore unresolved variables

Author: gossi

lib/clark-plugin.js

@@ -46,7 +46,8 @@ module.exports = class ClarkPlugin extends Plugin {
       // Iterate over numeric ranges with @for
       // Iterate over lists with @each
       require('postcss-advanced-variables')({
-        disable: '@mixin, @include, @content'
+        disable: '@mixin, @include, @content',
+        unresolved: 'ignore'
       }),
 
       // https://github.com/jonathantneal/postcss-short