How to add text outline/border ?

It is usually done using a Stack. However, the only option to customize the text is to change the TextStyle.

Look at the existing text animation widgets in the package, such as those in the lib/ directory, to understand how TextStyle is currently applied. Investigate how a Stack could be used to layer text for an outline effect, or if a new TextStyle property is needed. Check for any existing tests related to text styling to see how changes are validated.

Written by the indexing model from the issue text.