CSS Stylesheet Editor not functioning properly

the CSS Stylesheet Editor I’ve been using in Word press for my custom CSS will not scroll down the page so that I can continue to add to it. I have about 30 lines used and it won’t let me scroll to even view the last entry. It just pops back up to the top. I cleared my caches and refreshed page but it won’t let me work.

Any suggestions?

https://www.ashleythughes.com

thanks!