How to un-nest SCSS

Question

I have a scss file that includes nested styles. The file is intended to end up as the style sheet for Zendesk. Zendesk allows you to use scss like variables, and color functions, however, it does not allow you to use nested style declarations. Is there a way that I can un-nest the styles, while leaving variables and color functions as they are? I have tried looking for a "flatten" function to no avail.

For example:

Input

.footer {
  .footer-language-selector {
    color: lighten($color_3, 20%);
  }
}

Desired Output Note: both the variable and the color function remain as in the input

.footer .footer-language-selector {
  color: lighten($color_3, 20%);
}