Hello Norah. I like the"new look" . The last post showing first is great as some times this is what you wish to reply to, but how can it be numbered 1st?
As others point out this may create difficulties. "Reply to post" showing the previous one is great. Could "add reply" show the original post? This would be helpful when joining a lengthy thread. When I first saw your post I had to start at the "wrong end".
Another option that may be possible is for the original post to remain static near the top of the page whilst "replies" are being scrolled through. I also find the font a bit light as do others. Thanks to yourself and the team. I appreciate your work.