Show and Tell - Dash Bootstrap Components

So I’ve been giving this ago, using Koala to compile my custom scss file [table-custom.scss]:

@import "../flatly/_variables.scss.css";
@import "bootstrap.scss";
@import "../flatly/_bootswatch.scss.css";

#table-wrapper table{
  @extend .table;
  @extend .table-striped;
  @extend .table-hover;
  @extend .table-bordered;
  font-family: inherit;
  --border: none;
}

Using this code in my dash app:

app = dash.Dash(__name__, external_stylesheets=['/scss/table-custom.css'])

But when I run my app I seem to have lost all the flatly styling?

This is my folder structure:

Where’ve I gone wrong?