In Classic UI, you can use List Field Styles or UI Policies to conditionally change font color.

In Workspace, use Field Styles within List Layout configuration — DOM scripting is not recommended.

Avoid direct CSS manipulation for upgrade safety.

If you tell me:

Classic UI or Workspace?

Which table?

What condition?

Do you want color only or badge style?

I can give you an exact step-by-step solution tailored to your instance.