Because Inner is not static, it needs to be bound to an instance of the enclosing class (StInner).
If you want to make that in3, the following should work (this is from memory, so no warranty):
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus