Link to the code that reproduces this issue

https://github.com/thevisioner/next-turbo-css-modules-value-issue-reproduction

To Reproduce

1. Start the application in development using the --turbo flag (next dev --turbo).
2. Open the browser and inspect the Network tab in the DevTools (CSS files).
3. Look for the page.css file with the LayoutExample class.
4. Pay attention to the @media declaration.

Current vs. Expected behavior

In development using the --turbo flag (next dev --turbo) the CSS output contains the declaration, but the value (named 'compact') is not replaced with the actual value: @media compact {}.

However, in case without the --turbo flag (next dev) and in case of production build (next build) the value is replaced with the actual value: @media (max-width: 37.4375em) {}.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Home
  Available memory (MB): 32718
  Available CPU cores: 12
Binaries:
  Node: 20.10.0
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 15.0.0-canary.197 // Latest available version is detected (15.0.0-canary.197).
  eslint-config-next: 15.0.0-canary.197
  react: 19.0.0-rc-77b637d6-20241016
  react-dom: 19.0.0-rc-77b637d6-20241016
  typescript: 5.6.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

create-next-app, Developer Experience

Which stage(s) are affected? (Select all that apply)

next dev (local)

Additional context

No response