Extending @vuepress/theme-default does not load default component styles (sidebar, navbar)

[nancy1234567890]

Problem Summary

When extending the default theme in VuePress 2, my own custom SCSS and Vue single-file-component styles are applied correctly, but none of the default-theme component styles (e.g., sidebar, navbar, content layout) appear.

The HTML output itself is correct — .theme-container, .page, etc. exist but the default theme’s runtime styles (from VpSidebar.vue, VpNavbar.vue, etc.) never load.

Expected

Default theme component styles should load automatically when a custom theme extends @vuepress/theme-default.

Actual

Only my custom SCSS and <style> blocks apply;
no vp-* classes or default theme CSS appear in the final bundle.

I’m using a custom theme that extends @vuepress/theme-default but replaces several components:

/.vuepress/theme/
├── layouts/Layout.vue // custom
├── components/Sidebar.vue // custom
├── components/Navbar.vue // custom

Even though these components override the defaults, I expected the base default-theme styles (layout grid, typography, variables) to remain applied — similar to VuePress 1 behavior.
However, none of the default CSS (e.g., sidebar positioning, navbar background) appears unless I manually import index.scss

Technical Notes

VuePress version 2.0.0-rc.26

Bundler @vuepress/bundler-webpack

Extending pattern:

// index.js
extends: defaultTheme(options)

// client.js
extends: DefaultTheme

Followed the below guide for extending default theme
https://vuepress.vuejs.org/advanced/cookbook/making-a-theme-extendable.html