node.sass not compiling index.scss file with variables

Question

I'm trying to get node-sass to compile the following index.scss file. The error returned has to do with a call in bootstrap.scss file within node_modules.

@import 'node_modules/master.css/stylesheets/main';

@import './home';
@import 'header/-eader';
@import 'loading-spinner/loading-spinner';
@import 'message/message';
@import 'details/details';
@import 'footer/footer';

@import '../bin/temp/css/.sprites';

$font-size: 12pt;
$body-margin: 2rem;
$body-padding: .25rem;
$body-min-width: 23rem;
$body-max-width: 37.5rem;
$body-margin-right: auto;
$body-margin-left: auto;
$body-width: 100%;

html {
    font-size: $font-size;
}

body {
    margin-top: $body-margin;
    margin-bottom: $body-margin;
    margin-right: $body-margin-right;
    margin-left: $body-margin-left;
    padding: $body-padding;
    width: $body-width;
    min-width: $body-min-width;
    max-width: $body-max-width;
}

The command I'm trying to run is:

node-sass src/index.scss bin/dist/css/index.min.scss --source-map=true --source-map-contents --output-style=nested --indent-type=tab

I'm probably overlooking something simple, however I'm not able to find it.