"Import Code Snippets" not working

[WebMechanic]

Hello,
I have a fresh install of VitePress to document our new Style Guide and wanted to use the Import Code Snippets feature for .js, .css and .html fragments, but the file(s) are not included. I tried all sorts of pathnames with/without the base, relative, absolute, all to no avail.
Everything else works like a charme.

The project is a simple Vite Vue project. I then installed VitePress with yarn.
It resides in src/_docs/.vitepress.

Here's the config file

import {defineConfig} from 'vitepress'
export default defineConfig({
    base: '/src/_docs/',
    title: "The Style Guide",
    markdown: {
        lineNumbers: false,
        toc: {includeLevel: [1, 2]},
    }
}

Any advice and hints are welcome!
Thanks