How to override Vuetify 2 variables without using Vue CLI - vue.js

Question

The vuetify documentation only provides example for injecting sass variables using vue-cli configuration in vue.config.js
https://vuetifyjs.com/en/customization/sass-variables#markup-js-vue-config-sass-variables
What is the correct way to provide the modified vuetify variables when not using the CLI?
I am upgrading an older project from v1 (stylus) to v2 (sass) and I need to override some variables, lets say I only need to change the font-family to Arial.
I am also using treeshaking with vuetify.
Now I am kind of stuck because I don't know where to import the style overrides... Importing these in src/main.ts obviously does not work.
I have created a minimal repro here: https://github.com/Sharsie/vuetify-theme-repro/
What I have so far is a webpack config in build directory and style overrides in src/styles/main.scss
$body-font-family: Arial;
#import "~vuetify/src/styles/styles.sass";
Running the project creates a simple page that prints out computed styles for the v-app container
<v-app id="app">
<v-container>
<v-content>
<p>Wanted font-family: Arial</p>
<p>Current font-family: {{ fontFamily }}</p>
</v-content>
</v-container>
</v-app>

Answer 1

After digging through the source code of vue-cli, I figured out that the config just gets passed to sass-loader options, so the solution was pretty straightforward:
Instead of providing the stylesheet with variables through vue.config.js as such:
module.exports = {
css: {
loaderOptions: {
sass: {
data: `#import "~#/styles/main.scss"`,
},
},
},
}
You can provide it directly to sass-loader options in webpack config like this:
module.exports = {
...
module: {
rules: [
...
{
test: /\.(s?c|sa)ss$/,
use: [
'vue-style-loader',
'css-loader',
{
loader: 'sass-loader',
options: {
implementation: sass,
sassOptions: {
fiber: fibers,
},
prependData: `#import "~/styles/main.scss"`,
},
},
],
}
...
]
}
...
}
or for sass-loader<8.0.0
options: {
implementation: sass,
fiber: fibers,
data: `#import "~/styles/main.scss"`,
},