ExtendTheme type doesn't seem to work

[suren-atoyan]

Steps to reproduce

1. clone https://github.com/mui/pigment-css
2. cd examples/pigment-css-nextjs-ts
3. npm i
4. code .

Current behavior

VsCode doesn't recognize theme object.

I faced this issue in my project, but it does exist in the official pigment-css-nextjs-ts as well.

Expected behavior

I expect full TypeScript support.

Context

No response

Your environment

npx @mui/envinfo

  System:
    OS: macOS 14.2.1
  Binaries:
    Node: 18.18.0 - ~/.asdf/installs/nodejs/18.18.0/bin/node
    npm: 9.8.1 - ~/.asdf/plugins/nodejs/shims/npm
    pnpm: Not Found
  Browsers:
    Chrome: 124.0.6367.208
    Edge: Not Found
    Safari: 17.2.1
  npmPackages:
    @emotion/react:  11.11.4
    @emotion/styled:  11.11.5
    @mui/private-theming:  6.0.0-alpha.6
    @mui/styled-engine:  6.0.0-alpha.6
    @mui/system:  6.0.0-dev.240424162023-9968b4889d
    @mui/types:  7.2.14
    @mui/utils:  6.0.0-alpha.6
    @types/react: latest => 18.3.2
    react: latest => 18.3.1
    react-dom: latest => 18.3.1
    typescript: latest => 5.4.5

Search keywords: TypeScript, theme