the following page counter variables should end with !default to allow overwrites:

[thomasdumm]

In https://github.com/pressbooks/buckram/blob/master/styles/variables/_structure.scss
the following page countervariables should end with !default to allow overwrites:

// Page number style

$front-matter-page-number-left: counter(page, lower-roman) !default;
$front-matter-page-number-right: counter(page, lower-roman) !default;

$introduction-page-number-left: counter(page) !default;
$introduction-page-number-right: counter(page) !default;

$part-page-number-left: counter(page) !default;
$part-page-number-right: counter(page) !default;

$chapter-page-number-left: counter(page) !default;
$chapter-page-number-right: counter(page) !default;

$back-matter-page-number-left: counter(page) !default;
$back-matter-page-number-right: counter(page) !default;