A RichText panel class for the UI that matches the word "invulnerable" (case-insensitive) and customizes its appearance. It sets text color to black, adds a yellow text stroke with width 3, and is intended for styled rich text rendering.
using Sandbox.UI;
[RichTextPanel( @"\b[Ii]nvulnerable\b" )]
public class RichTextInvulnerable : RichTextBase
{
public override Color Color => Color.Black;
//public override int? FontWeight => 800;
public override float? TextStrokeWidth => 3f;
public override Color? TextStrokeColor => Color.Yellow.WithAlpha(0.9f);
}