Why did my #form-outer stop expanding?

My codpen: https://codepen.io/Jediadam/pen/xzdmPL

What exactly do you mean? Add details to your question.

I want the #form-outer to expand down the page as I type. I think it was doing that before but now it’s not.

You can’t do it with CSS. You have to use JavaScript and textarea tag. You can see an example here: textarea expand as you type.
If you want to expand inputs I haven’t answer on it.

That just gets rid of all the white.

I chose not to save it that way because every time I delete the div it gets rid of all the white.