SassError: Undefined mixin.

[artdias90]

Followed your installation but not being able to run project after adding custom styles.

Error: ./src/custom-theme.scss
Module build failed (from ./node_modules/mini-css-extract-plugin/dist/loader.js):
ModuleBuildError: Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
SassError: Undefined mixin.
   ╷
36 │ @include ngx-bottom-nav-theme($theme); // <-- include the bottom nav theme
   │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   ╵
  src/custom-theme.scss 36:1  root stylesheet

with latest LTS ngCLI + Material as of today