Hi there @bowiesushio521f
There’s not built-in property to handle this, and there’s no block that you can use if you were to create a custom function.
I think the idea of a TextInput changing colour when it gets/loses focus definitely sounds nice, but at the same time I don’t think the absence of this feature would put any of your users off, nor should it prevent you from completing the rest of your sign in page.
Hope that helps.