Build-css failing to replace variable value

[Theeeus]

I'm getting the error below on build. The light-bootstrap-dashboard.css file is created normally but one of the variables ($sidebar-width) is not being replaced.

Lexical error on line 1: Unrecognized text. Erroneous area: 1: 100% - $sidebar-width ^.........^

This is my script:
"build-css": "node-sass-chokidar --include-path ./src --include-path ./node_modules src/ -o src/",