mode return is always dark or light

[nyssance]

Describe the feature in detail (code, mocks, or screenshots encouraged)

Need return an option: system or undefined.
Now the first time return undefined then auto set light/dark.

What type of pull request would this be?

Enhancement

Provide relevant links or additional information.

No response

[huntabyte]

You should use userPrefersMode if you also want system as an option.