Text overflow CSS

Question

How do I make the text overflows like in this awesome code of Tristan?
New text stuck at the bottom and old text scroll upwards.

I try the overflow:auto in css but old text stuck at the top and I have to scroll down to see new text.
I hope my question makes sense 😁

https://code.sololearn.com/WqjnZwxCjq7N/?ref=app

Answer 1

line 33-36
if (index < message.length) {
pre = document.getElementById('style-text');
pre.scrollTop = pre.scrollHeight;
writeStyleChar(message[index++]);

Answer 2

Thank you!
You're my favorite person of the day 😁